HARQUAHALA FEB 14, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ********** | *** 191 ** | ********** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - FEB 13 v = Heat Units accumulated from JAN 1 - FEB 7 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Cotton seedling disease in AZ is caused primarily by Rhizoctonia solani & Thielaviopsis basicola. Disease can usually be prevented by planting when soils are 65F (6-8 in. depth); by using quality seed that emerges & develops roots rapidly; by rotating out of cotton for at least 2 years; & by treating seed with fungicides. Seed is treated by the supplier or as hopper box treatments. Combinations work best, such as PCNB for Rhizoctonia & triadimenol for Thiela- viopsis with systemics (i.e. carboxin, chloroneb) & protectants (i.e. Thiram, Captan). Fungicides active against Pythium, such as metalaxyl, usually are not necessary. In-furrow applications of suitable fungicides should be considered for replant IF disease has been confirmed & the agent identified (MO 2/99). WEATHER UPDATE -------------------------------- Last Week : FEB 7 - FEB 13 HIGH LOW HUs Recorded 69 35 30 FORECAST: Sunny and cool early in the week with very low humidity. A warming trend is expected later in the week with temperatures rising to 2-4 degrees above normal by Friday. Little chance for rain. Cotton advisories are available via AZMET's Internet Web Page each Monday about noon. The web page address is: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 51.4 FEB 10 ; Min = 40.2 FEB 12 AGRONOMY UPDATE -------------------------------- The early weeks of 1999 have been very dry, and as a result preparations and plans for planting are proceeding much earlier than we were able to accomplish in 1998. There is often a strong incentive in managing for an early crop. Earliness can be briefly defined as moving through and completing the primary fruiting cycle in a complete (high fruit retention level), fast, and efficient fashion. In realizing maximum yield potential, planting date is indeed very important. An early, optimum date of planting should take into account soil temperature conditions, the 5 day forecast, and the variety type. Optimum soil temperatures for planting are 65 F at 8 A.M., with absolute minumums of 55 F. Soil temperatures will also drop with a water-up irrigation. (JCS 2/12/99) HARQUAHALA FEB 21, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ************ | **** 240 *** | ************ | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - FEB 20 v = Heat Units accumulated from JAN 1 - FEB 14 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Cotton seedling disease in AZ is caused primarily by Rhizoctonia solani & Thielaviopsis basicola. Disease can usually be prevented by planting when soils are 65F (6-8 in. depth); by using quality seed that emerges & develops roots rapidly; by rotating out of cotton for at least 2 years; & by treating seed with fungicides. Seed is treated by the supplier or as hopper box treatments. Combinations work best, such as PCNB for Rhizoctonia & triadimenol for Thiela- viopsis with systemics (i.e. carboxin, chloroneb) & protectants (i.e. Thiram, Captan). Fungicides active against Pythium, such as metalaxyl, usually are not necessary. In-furrow applications of suitable fungicides should be considered for replant IF disease has been confirmed & the agent identified (MO 2/99). WEATHER UPDATE -------------------------------- Last Week : FEB 14 - FEB 20 HIGH LOW HUs Recorded 75 39 49 FORECAST: Sunny with mild days and cool nights early in the week. Sunny and much warmer late in the week with temperatures running about 5-7 degrees above normal. The current forecast should warm Yuma-area soil temperatures to acceptable planting levels late in the week. Growers planning to plant are encouraged to check the weekend forecast which presently contains a chance of rain in S. California. A GOOD PLANTING FORECAST: Sunny with highs in the low 80s and lows in the upper 40s or above. Last Week's 8am Soil Temp: Max = 53.1 FEB 19 ; Min = 45.3 FEB 14 AGRONOMY UPDATE -------------------------------- During the early stages of the planting season we can often encounter soil temperatures that are not optimum. Optimum soil temperatures for planting cotton are usually considered as being 65 F at 8 A.M., for several (three) days prior to planting. Cotton can be planted in soils that are below optimum temperature conditions and still germinate, emerge, and establish a satisfac- tory stand. However, 55 F should be considered as a minimum soil temperature for planting cotton. Planting cotton into soils that are 55 F (or less) at 8 A.M. is a good prescription for poor germination (even with strong, vigorous seed), seedling disease, and poor stands. For early plantings use varieties with good seedling vigor, and delay using those known to be weak.(JCS 2/20/99) HARQUAHALA FEB 28, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | *************** | ****** 299 **** | *************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - FEB 27 v = Heat Units accumulated from JAN 1 - FEB 21 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Cotton seedling disease in AZ is caused primarily by Rhizoctonia solani & Thielaviopsis basicola. Disease can usually be prevented by planting when soils are 65F (6-8 in. depth); by using quality seed that emerges & develops roots rapidly; by rotating out of cotton for at least 2 years; & by treating seed with fungicides. Seed is treated by the supplier or as hopper box treatments. Combinations work best, such as PCNB for Rhizoctonia & triadimenol for Thiela- viopsis with systemics (i.e. carboxin, chloroneb) & protectants (i.e. Thiram, Captan). Fungicides active against Pythium, such as metalaxyl, usually are not necessary. In-furrow applications of suitable fungicides should be considered for replant IF disease has been confirmed & the agent identified (MO 2/99). WEATHER UPDATE -------------------------------- Last Week : FEB 21 - FEB 27 HIGH LOW HUs Recorded 79 39 60 FORECAST: Sunny with very warm temperatures through mid-week. A storm system will move across the Great Basin later in the week, bringing windy weather and a return to near-normal temperatures on Thursday and Friday. Present forecasts do not call for any precipitation with this storm system. GOOD PLANTING FORECAST: Sunny with highs above 80F & lows above 48F. This advisory is available on the Internet each Monday at: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 55 FEB 26 ; Min = 50.3 FEB 23 AGRONOMY UPDATE -------------------------------- The most important factors to consider in an early/optimum planting include: satisfactory soil temperatures for rapid germination and establishment and a good 5-day weather forecast. Soil temperatures have recently been approaching satisfactory levels for planting cotton (>55 F) in many areas. Weather condi- tions have been conducive to planting and achieving an early, vigorous stand for this season. In the early stages of the planting season, planting varieties with low seedling vigor should be done with caution. The weekly cotton advisories and other supplemental bulletins are available at the internet websites for AZMET (http://ag.arizona.edu/azmet) and the Arizona Cotton Information Site (ACIS) (http://ag.arizona.edu/cotton) (JCS 2/27/99). HARQUAHALA MAR 7, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ****************** | ******* 370 ****** | ****************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 6 v = Heat Units accumulated from JAN 1 - FEB 28 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Cotton seedling disease in AZ is caused primarily by Rhizoctonia solani & Thielaviopsis basicola. Disease can usually be prevented by planting when soils are 65F (6-8 in. depth); by using quality seed that emerges & develops roots rapidly; by rotating out of cotton for at least 2 years; & by treating seed with fungicides. Seed is treated by the supplier or as hopper box treatments. Combinations work best, such as PCNB for Rhizoctonia & triadimenol for Thiela- viopsis with systemics (i.e. carboxin, chloroneb) & protectants (i.e. Thiram, Captan). Fungicides active against Pythium, such as metalaxyl, usually are not necessary. In-furrow applications of suitable fungicides should be considered for replant IF disease has been confirmed & the agent identified (MO 2/99). WEATHER UPDATE -------------------------------- Last Week : FEB 28 - MAR 6 HIGH LOW HUs Recorded 82 41 70 FORECAST: NOTE: The main Pacific storm track (jet stream) is forecast to move south into AZ this week. Passing Pacific storms will have a greater impact on AZ weather by late in the week. FORECAST: Mostly clear & cool Monday followed by gradual warming to above normal temperature conditions mid-week. A Pacific storm system is forecast to pass through the southwest on Friday bringing windy, much cooler weather & a chance for rain. A second Pacific storm may impact AZ weather by Sunday. GOOD PLANTING FORECAST: Sunny with highs above 80F & lows above 48F. Last Week's 8am Soil Temp: Max = 59.5 MAR 4 ; Min = 53.6 FEB 28 AGRONOMY UPDATE -------------------------------- A very susceptible stage of development for a young cotton seedling is the period immediately following planting. When the seed is placed in the ground it begins absorb (imbibe) water and initiate a rapid increase in metabolic activity. Much of this physiological activity takes place within the first few hours after planting. It is at this stage when a young seedling is very sensi- tive to chilling injury. If soil temperatures are 50 F or less while the seed is first imbibing water, damage to the seedling can occur, reducing vigor and enhancing the chances for seedling diseases. The cotton advisories and other bulletins are available at the AZMET website (http://ag.arizona.edu/azmet) and the AZ Cotton Info. Site (ACIS)(http://ag.arizona.edu/cotton) (JCS 3/6/99). HARQUAHALA MAR 14, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ******************** | ******** 404 ******* | ******************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 13 v = Heat Units accumulated from JAN 1 - MAR 7 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Assessing crop risk of PBW infestation is dependent on weather, current & past cultural practices, & planting dates. Dry winter conditions favor PBW survival of diapausing larvae & late emergence moths. More moths extend into periods of peak squaring. Risk is also dependent on area crop production practices. The following practices favor PBWs: previous season's late production of small green bolls (> Sept.), minimal crop shredding & burial (<4 inches deep), minimal soil preparation, cotton following (late) cotton, & early planted/squaring cotton. Early crop termination & deep plowdown, winter cover crops &/or winter irrigations, crop rotation, & optimal planting dates are all techniques for reducing the risk of early season PBW infestation. WEATHER UPDATE -------------------------------- Last Week : MAR 7 - MAR 13 HIGH LOW HUs Recorded 70 38 34 FORECAST: A major Pacific storm will pass through Arizona on Tuesday & Wednesday. Cloudy, windy and mild on Monday, with rain developing in western AZ by Monday evening. Cloudy, windy & much cooler Tuesday with rain likely in most production areas. Mostly sunny and cool Wednesday; then gradual warming to above normal tempera- tures by late in the week. Soils typically do not warm to acceptable levels for rapid germination until highs exceed 80F and lows stay in the upper 40s or above. Last Week's 8am Soil Temp: Max = 57.3 MAR 7 ; Min = 51.9 MAR 8 AGRONOMY UPDATE -------------------------------- Combinations of factors can affect cotton germination such as: temperatures, soil crusting, depth of seed placement, salinity, and herbicide placement. Cotton is a relatively salt tolerant crop. However, during germination and emergence, cotton can be affected by lower salt concentrations than after establishment. For example, salt concentrations resulting in soil electrical conductivities (EC) of 5 mmhos/cm (or dS/m) in the zone of seed placement can reduce germination and seedling vigor. This can be critical if other factors such as soil temperatures, seedling vigor of the variety, etc. are marginal. Every row irrigation will accumulate salts in the middle of the bed. Alternate row irrigations can move salts past the seedline. (JCS 3/12/99) HARQUAHALA MAR 21, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | *********************** | ********** 454 ******** | *********************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 20 v = Heat Units accumulated from JAN 1 - MAR 14 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Assaying fields for Root-knot nematode has been difficult this year because of the lack of winter rain. Many fields are dry below the plow layer where samples would normally be taken. However, fields that have been tested and have detectable levels of Root-knot nematode or are known to have been infested previously should be considered for pre-plant fumigation with Telone. Optimum conditions for application are: (1) soil moisture at injection, preferably 12 inches or more below seedling depth, at 50% field capacity; (2) absence of cotton trash; (3) soil temperatures between 60 - 80 F; (4) application 10-14 days before planting. WEATHER UPDATE -------------------------------- Last Week : MAR 14 - MAR 20 HIGH LOW HUs Recorded 75 40 50 FORECAST: Mostly sunny, warm and dry through Wednesday. Expect temperatures to run 5-10 degrees above normal through Wednesday. A Pacific storm system is forecast to move through AZ Thursday, bringing cooler weather and a chance for rain. This system does not appear particularly cold, and current forecasts project a return to normal temperatures by Friday or Saturday. Soils typically warm to levels that support rapid germination when highs exceed 80F and lows stay in the upper 40s or above. Internet Address for Cotton Advisories: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 57.8 MAR 20 ; Min = 52.1 MAR 18 AGRONOMY UPDATE -------------------------------- Cotton establishment does not require a great deal of N. Plant uptake of N rapidly increases as plants begin to form the first pinhead squares. Therefore, sufficient N can be supplied to a young cotton crop for establishment from a relatively small amount of residual soil N. Residual soil N levels of 10 ppm nitrate-N in the top 1 foot of soil equates to about 40 lb. nitrate- N/acre, which is sufficient to start a cotton crop. For optimum efficiency of N fertilization, it is best to begin N applications just prior to pinhead square formation in increments of approximately 40 - 70 lb.N/acre/application. Advisories are available on-line @ http://ag.arizona.edu/azmet or http://ag.arizona.edu/cotton (JCS 3/20/99) HARQUAHALA MAR 28, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ************************** | *********** 515 ********** | ************************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 27 v = Heat Units accumulated from JAN 1 - MAR 21 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Assaying fields for Root-knot nematode has been difficult this year because of the lack of winter rain. Many fields are dry below the plow layer where samples would normally be taken. However, fields that have been tested and have detectable levels of Root-knot nematode or are known to have been infested previously should be considered for pre-plant fumigation with Telone. Optimum conditions for application are: (1) soil moisture at injection, preferably 12 inches or more below seedling depth, at 50% field capacity; (2) absence of cotton trash; (3) soil temperatures between 60o - 80o F; (4) application 10-14 days before planting. WEATHER UPDATE -------------------------------- Last Week : MAR 21 - MAR 27 HIGH LOW HUs Recorded 78 42 62 FORECAST: Mostly sunny & very warm through Wednesday. A Pacific storm system will move into AZ on Thursday, bringing windy; cloudy; & cooler weather with a chance for scattered showers. This storm should exit AZ by Friday, but cooler weather is expected to linger until Saturday. Sunny & warmer weather is expected by Sunday. Soils typically warm to levels that support good germination when daytime highs are above 80F and lows remain in the upper 40s or higher. This advisory is available on the Internet each Monday at noon. Log on using the address http://ag.arizona.edu/azmet and click the box labeled Cotton Advisories. Last Week's 8am Soil Temp: Max = 64 MAR 26 ; Min = 57 MAR 22 AGRONOMY UPDATE -------------------------------- One of the characteristics common to full season, indeterminate varieties is the tendency to experience increased vegetative growth and reduced yield po- tentials when planted beyond an optimum window. In general, full season vari- eties should be planted before heat unit accumulations after Jan. 1 (HU/Jan.1) extend significantly past 600 to 700. The HU/Jan. 1 accumulations are listed in the figure above for this area. Subsequent plantings should use medium or short season (more determinate) varieties. There are several excellent medium and short season varieties to select from which can provide good yield poten- tials with proper management. Advisories and other cotton-related information can be accessed on the web at http://ag.arizona.edu/cotton (JCS 3/27/99) HARQUAHALA APR 4, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | **************************** | ************ 558 *********** | **************************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 3 v = Heat Units accumulated from JAN 1 - MAR 28 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- The longevity & efficacy of any product depends in part on the extent of its use. Due to the capacity for many insects to overcome our control technologies, we must balance the need to achieve economic pest control with risks of resistance that might lower the future utility of the technology. Bt cotton currently has a regulated requirement for refuge plantings to preserve the susceptible gene pool. Most experts agree that the larger the non-Bt refuge acreage, the better chance that we will have for preserving the technology by producing susceptible PBW moths. Refuges also have the best chance for working if they are placed as close as possible to the Bt crop and on as much acreage as is practically possible for the given pest management situation (pe 4/99). WEATHER UPDATE -------------------------------- Last Week : MAR 28 - APR 3 HIGH LOW HUs Recorded 73 41 45 FORECAST: Sunny with a gradual warming trend through Tuesday. Another storm is predicted to pass near AZ on Wednesday, bringing clouds, cooler temperatures and a chance for showers. This storm is not projected to be as cold as the previous one, and cold weather is not expected late in the week. It is important to note that the storm track (jet stream) remains near AZ at this time. Storm systems can be expected to pass through/near AZ every 3-4 days until the jet stream moves north again. Last Week's 8am Soil Temp: Max = 61.5 APR 1 ; Min = 48.8 APR 3 AGRONOMY UPDATE -------------------------------- With the recent rains and cool weather, soil conditions may be less than opti- mal for planting. It is important to consider that a very sucseptible stage of development for a young cotton seedling is the period immediately following planting. When the seed is placed in the ground it begins absorb (imbibe) water and initiate a rapid increase in metabolic activity. Much of this phys- iological activity on the part of the seed takes place within the first few hours after planting. If soil temperatures are 50 F or less while the seed is first imbibing water, severe damage to the seedling can occur, which can reduce vigor and enhance the chances for seedling diseases. Advisories (and cotton info.) are avail. on the web http://ag.arizona.ed/cotton (JCS 4/3/99) HARQUAHALA APR 11, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ***************************** | ************ 581 ************ | ***************************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 10 v = Heat Units accumulated from JAN 1 - APR 4 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- The longevity & efficacy of any product depends in part on the extent of its use. Due to the capacity for many insects to overcome our control technologies, we must balance the need to achieve economic pest control with risks of resistance that might lower the future utility of the technology. Bt cotton currently has a regulated requirement for refuge plantings to preserve the susceptible gene pool. Most experts agree that the larger the non-Bt refuge acreage, the better chance that we will have for preserving the technology by producing susceptible PBW moths. Refuges also have the best chance for working if they are placed as close as possible to the Bt crop and on as much acreage as is practically possible for the given pest management situation (pe 4/99). WEATHER UPDATE -------------------------------- Last Week : APR 4 - APR 10 HIGH LOW HUs Recorded 67 36 24 FORECAST: Another storm system will pass through AZ on Monday & Tuesday, bringing high winds, cooler weather & a chance for rain. The jet stream is projected to move north of AZ with the passage of this storm, allowing a large ridge of high pressure to develop over AZ by mid-week. Temperatures should rebound to normal levels by Wednesday with continued warming through Friday. Temperatures in excess of 90 F are likely in central & western AZ by Friday. Soils typically warm to levels that support rapid germination when highs exceed 80F and lows stay in the upper 40s or above. Last Week's 8am Soil Temp: Max = 55 APR 9 ; Min = 48 APR 5 AGRONOMY UPDATE -------------------------------- Optimum stand populations for cotton can range from 25,000 to 50,000 plants per acre (ppa) for most varieties. Minimum average populations for cotton are commonly identified at about 20,000 ppa. Adjusting seeding rates during the early stages of planting must take into account a number of factors such as: general seedling vigor of the variety being used, soil temperatures, soil sa- linity, herbicide program, etc. When faced with more adverse factors, a high- er seeding rate will be needed. For example, if a stand of 40,000 ppa is a target, the variety has 5,000 seeds/pound, a successful emergence rate of 50% may would require 16 lbs. seed/acre. Advisories are also available on the web http://ag.arizona.edu/cotton (JCS 4/8/99) HARQUAHALA APR 18, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ********************************* | ************** 657 ************** | ********************************* | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 17 v = Heat Units accumulated from JAN 1 - APR 11 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- As we warm up, plant growth rates increase & concern for damage by early season insects lessens. Few insects warrant sprays early season; however, a wide variety of insects feed on & cause incidental or serious damage to individual plants. Flea beetles, thrips, beet armyworms, darkling beetles, fleahoppers & aphids may each be present. Their presence may also be important to the build- up of natural enemies that become important in limiting the damage of future pest infestations. Once plants produce true leaves, damage by flea beetles & beet armyworms becomes less important. Darkling beetles are occasional pests that are often related to surrounding desert vegetation. Aphids tend to decline quickly once temperatures warm up & solar radiation increases (pe 4/19). WEATHER UPDATE -------------------------------- Last Week : APR 11 - APR 17 HIGH LOW HUs Recorded 82 45 75 FORECAST: Sunny, warm and dry through mid-week. A storm system will drop down into AZ on Wednesday or Thursday, bringing windy & somewhat cooler weather. Present fore- casts indicate little or no precipitation is likely with this storm. The cooler weather following storm passage should drop temperatures back down to normal for this time of year. This advisory is available on the Internet each Monday at noon. Log on using the address http://ag.arizona.edu/azmet and click the box labeled Cotton Advisories. Last Week's 8am Soil Temp: Max = 62.2 APR 15 ; Min = 53.3 APR 11 AGRONOMY UPDATE -------------------------------- Young seedlings should be evaluated both above and below ground, in evaluating overall health and vigor. The hypocotyl tissue (between the point of seed placement and the cotyledons or seed leaves) should be white under the best of circumstances. However, it is not unusual to experience some slight brown dis- coloration in this area. The below ground portion of the plant should be checked regularly for the appearance of any disease. Tap roots should be ex- tending rapidly at early stages of growth at a rate of approximately 1 in. per day. Tap roots should be approximately 12 in. deep at 1st true leaf and 24 in. by the 2nd to 3rd leaf. Hot site: http://ag.arizona.edu/cotton (JCS 4/17/99) HARQUAHALA APR 25, 1999 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ************************************** | ***************** 751 **************** | ************************************** | | | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 24 v = Heat Units accumulated from JAN 1 - APR 18 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- As we warm up, plant growth rates increase & concern for damage by early season insects lessens. Few insects warrant sprays early season; however, a wide variety of insects feed on & cause incidental or serious damage to individual plants. Flea beetles, thrips, beet armyworms, darkling beetles, fleahoppers & aphids may each be present. Their presence may also be important to the build- up of natural enemies that become important in limiting the damage of future pest infestations. Once plants produce true leaves, damage by flea beetles & beet armyworms becomes less important. Darkling beetles are occasional pests that are often related to surrounding desert vegetation. Aphids tend to decline quickly once temperatures warm up & solar radiation increases (pe 4/19). WEATHER UPDATE -------------------------------- Last Week : APR 18 - APR 24 HIGH LOW HUs Recorded 87 50 95 FORECAST: Sunny, warm & dry through Tuesday. Another storm will pass through AZ on Wednesday and bring windy & cooler weather late in the week. Present forecasts indicate this storm will be dry, and little rain is forecast to develop with this storm. Temperatures should average about 3 degrees below normal for the week. This advisory as well as links to National Weather Service forecasts are avail- able on the AZMET Web Page at: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 69.5 APR 22 ; Min = 63.4 APR 18 AGRONOMY UPDATE -------------------------------- With the cool weather we have experienced recently many fields are experienc- ing slow growth and low vigor. Young seedlings should be evaluated both above and below ground in evaluating overall health and vigor. The hypocotyl tissue (between the point of seed placement and the cotyledons or seed leaves) should be white under the best of circumstances. However, it is not unusual to exper- ience some slight brown discoloration in this area. The below ground portion of the plant should be checked regularly for the appearance of any disease. Tap roots should be approximately 12 in. deep at 1st true leaf and 24 in. by the 2nd to 3rd leaf. The formation of secondary roots is an indication of good root health. UA cotton web site: http://ag.arizona.edu/cotton (JCS 4/24/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY MAY 2, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15******** 396 | | v | | | | | | | | 4/1 ***** 261 | |v | | | | | | | | 4/15**** 183 | | | | | | | | | | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to MAY 1 v = Heat Units on APR 25; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Early-season insect scouting is akin to good detective work with an eye towards the unusual. Under the majority of cases, early season insect presence neither jeopardizes yield nor requires control. However, a misstep early in the season in identifying an usually severe or persistent infestation could cost time & yield in crop development & money to the grower. With the excessive winds & sand movement present across the state last week (see below), young seedlings will begin to show signs of scarring, leaf deformity, square desiccation & abortion, & terminal loss or forking. These signs may be confused with insect damage, especially 2-3 weeks later. Symptoms like this when caused by insects are rarely found without significant numbers of insects also present (pce 5/3). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : APR 25 - MAY 1 HIGH LOW HUs DEWPT RAIN Recorded 79 46 68 39 0.02 A Pacific storm system will pass north of AZ on Monday, producing dry & windy conditions with mild temperatures. High pressure will develop over AZ my mid- week, and bring the first spell of hot weather for the season. Temperatures should approach 100 F or higher in central and western AZ by Thursday. Little chance for precipitation through Friday. This advisory as well as links to National Weather Service forecasts are avail- able on the AZMET Web Page at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 11% complete at this time. HU last week = 68. Heat Unit accumulation since Jan 1 = 817. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .18" .18" .18" .18" .18" AGRONOMY UPDATE -------------------------------- With the recent winds that we have experienced in this region it is almost amazing that any small squares or terminals have survived. It seems like a miracle to find young plants that weren't sawed of at the ground considering the strength and duration of the wind and the amount of sand that blasted across many fields. In fact, many plants probably do have new cuts and abra- sions at the soil line from being whipped around in the wind. These wounds can serve as points of infection and/or damage to the plant's vascular system. Therefore, it will be important to carefully inspect fields in the next week to assess damage and overall crop condition. We can also certainly expect to see a lot of split terminals in the next couple of weeks. (JCS 5/1/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY MAY 9, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15********** 490 | | v | | | | | | | | 4/1 ******* 355 | | v | | | | | | | | 4/15****** 277 | | | | | | | | | | 5/1 ** 90 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to MAY 8 v = Heat Units on MAY 2; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Terminal loss as a result of physical injury to the meristem is unpreventable. But with close observation & quick action, insect-related terminal loss may sometimes be limited. Thrips are the major insect cause of terminal loss in AZ. Thrips are slender, straw to brown-colored active insects that hop & fly when disturbed. Immatures are slower moving, light to white-colored, & wingless, & tend to be concealed in folded leaves or scarred tissues. Adults are strongly attracted to certain colors & may be seen swarming the white shirts of crop scouts. Thrips play a complex role in cotton as pest, predator, & host to other predaceous insects. This latter role may be important to the establishment of a healthy complement of useful predators season-long (pce 5/10). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 2 - MAY 8 HIGH LOW HUs DEWPT RAIN Recorded 87 47 91 35 0.00 Mostly sunny, warm and dry this week. Temperatures will increase from near normal levels on Monday to about 5 degrees above normal on Friday. Little chance for precipitation through Friday. This advisory & local AZMET weather information is available from the AZMET Internet Web Page at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 16% complete at this time. HU last week = 91. Heat Unit accumulation since Jan 1 = 911. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .22" .22" .22" .22" .22" AGRONOMY UPDATE -------------------------------- One possible consequence of strong winds early in the season can be terminal damage from blowing soil particles. Young cotton plants are particularly susceptible to this type of terminal damage between the time the first true leaves are set to the occurrence of first pinhead squares (PHS). Evidence of terminal loss will often be the appearance of an over-extended petiole from a leaf occurring just below the terminal. Windy conditions can also cause rapid drying of the surface soil, which can sometimes be a problem for small seed- ling plants, particularly in coarser textured soils. Crop and soil conditions should be monitored regularly in an effort to manage for a stable, well-found- ed crop. Cotton web site: http://ag.arizona.edu/cotton (JSC 5/8/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY MAY 16, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15************ 605 | | v | | | | | | | | 4/1 ********* 470 | | v | | | | | | | | 4/15******** 392 | |v | | | | | | | | 5/1 **** 205 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to MAY 15 v = Heat Units on MAY 9; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Overwintering emergence of PBW moths should be evident in pheromone traps by now. Traps are useful indicators of general trends only & should not be used for making field level control decisions. All moths emerging now are considered "suicidal," because susceptible squares are not yet available to host PBWs. Dry winters tend to delay emergence of overwintering moths. Lygus at this time of season are generally confined to alfalfa (& some weeds & other hosts). Now is the time to initiate management of your local alfalfa such that a portion of it is always uncut & available to moving Lygus adults. This tactic will be very beneficial in preventing their movement into cotton, especially from adjacent alfalfa fields. Alternate cutting & watering schedules now (pce 5/17/99). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 9 - MAY 15 HIGH LOW HUs DEWPT RAIN Recorded 90 54 116 38 0.00 High pressure will develop over AZ this week, bringing sunny and dry conditions with above normal temperatures. Expect daytime temperatures to exceed 100 F by mid-week in many western and central production areas. Some cooling is expected by Friday as a storm system moves across the Great Basin. This advisory is available on the Internet each Monday at noon. Log on using the address http://ag.arizona.edu/azmet and click the box labeled Cotton Advisories. Spring emergence of PBW should be about 25% complete at this time. HU last week = 116. Heat Unit accumulation since Jan 1 = 1026. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .24" .24" .24" .24" .24" AGRONOMY UPDATE -------------------------------- Crop development and progress in many areas is slower than normal and certain- ly later than what we would like to have for this time of the year (see the crop develoment figure at the top of the page). However, in terms of heat unit (HU) accumulations, plant development is proceeding very close to normal. At this stage in the season it is important to monitor early plant development. Key points to look for include: 1) the first pinhead squares (PHS) and the first fruiting branch, which should occur on nodes 5, 6, or 7; 2) any signs of terminal damage (will commonly cause a delay in fruiting); and 3) tracking mainstem node number in relation to herbicide applications. Roundup applications to RR plants need to be made by the 4 true leaf stage. (JCS 5/15/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY MAY 23, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15************** 718 | | v | | | | | | | | 4/1 ************ 583 | | v | | | | | | | | 4/15********** 505 | | v | | | | | | | | 5/1 ****** 318 | | | | | | | | | | 5/15** 111 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to MAY 22 v = Heat Units on MAY 16; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Thrips injury is apparent in some fields. Symptoms include crinkling & silvering of cotyledons, leaf & terminal tissues. Adults, active movers, can be seen with the naked eye. Slow-moving nymphs may be seen with a hand lens. Injury often lags behind infestation, so control decisions must be based on the presence of the insects only. Even then chemical control may not be necessary during this relatively warm weather while plants are actively growing. Adults will readily move in or out of a field depending on its attraction relative to adjacent hosts. Now is the time to initiate management of your local alfalfa such that a portion of it is always uncut & available to moving Lygus adults. Alternate cutting & watering schedules now (pce 5/24/99). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 16 - MAY 22 HIGH LOW HUs DEWPT RAIN Recorded 93 50 113 34 0.00 An upper level low pressure center will drift across northern AZ Monday & Tues- day. This storm is not expected to impact weather in most production areas with the exception of southeast AZ where some cloudiness and a few widely scattered showers may develop. Overall, this should be a decent weather week for developing cotton stands. Expect sunny skies with warm days & mild nights. A slow warming trend is expected late in the week. Temperatures should average near normal for the week. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 36% complete at this time. HU last week = 113. Heat Unit accumulation since Jan 1 = 1139. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .23" .23" .23" .23" .23" AGRONOMY UPDATE -------------------------------- Timing the first post-plant irrigation can have a significant impact on sub- sequent crop development and even lint yield. Determinate varieties are more sensitive to water stress at early stages of the season. The best approach to early season irrigation management for optimum crop benefit, is to time the first in-season irrigation when the plant-available water (PAW) in the soil is depleted to approximately 50 - 60% PAW (still remaining). This point will vary among fields due to soil texture, weather, and previous irrigations. Optimum timing of this first irrigation requires soil and crop monitoring. Following the cool spring that we have experienced, many fields need to be managed for a higher level of vigor. Water stress should be avoided. (JCS 5/22/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY MAY 30, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | 3/15***************** 858 | | v | | | | | | | | 4/1 ************** 723 | | v | | | | | | | | 4/15************* 645 | | v | | | | | | | | 5/1 ********* 458 | |v | | | | | | | | 5/15***** 251 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to MAY 29 v = Heat Units on MAY 23; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Like last year, Pale-Striped Flea Beetles have been present in many area fields this year. Adults bear brown & white longitudinal stripes & readily hop when disturbed. Their preferred food sources are the succulent cotyledon leaves early on & lower leaves later in the season. They have chewing mouthparts that score the upper (most often) & lower surfaces of these leaves without causing holes. Fresh wounds bleed plant sap & scarred tissues turn light brown in time. Flea beetles only rarely attack true leaves while cotyledons are present & attractive. Damage is largely cosmetic & often limited to field edges, though remedial action (incl. advanced irrigations) may be needed when the water-balance of a young stand is jeopardized (5/31). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 23 - MAY 29 HIGH LOW HUs DEWPT RAIN Recorded 97 58 140 42 0.00 An unusual week of weather is in store for early June. The week will begin sunny & mild, but a Pacific low pressure system will begin to influence AZ weather by Wednesday. The low will generate increasing humidity, cloudy skies, winds, & cooler temperatures by mid-week. Scattered showers & thunderstorms are possible Wednesday, especially in higher elevation areas. A gradual warm- ing trend will develop late in the week, but temperatures will still average 5-10 degrees below normal for the week. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 52% complete at this time. HU last week = 140. Heat Unit accumulation since Jan 1 = 1279. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .46" .24" .24" .24" .24" AGRONOMY UPDATE -------------------------------- June and the crop production period extending up to the beginning of the monsoon season is often referred to as the "Prime Time" for Arizona cotton. Cotton plants can do very well in terms of growth and fruit retention (FR) under hot and dry conditions provided primarily that they are well irrigated (water stress eliminated) and protected from pests. Split applications of fer- tilizer N are also important to provide between the formation of early squares and peak bloom. Most cotton fields in Arizona at this time need more vigor. High crop vigor (often measured with a height:node ratio, HNR) indicates more rapid fruiting branch and fruiting site formation. Crop monitoring and manage- ment for high FR and crop vigor are very important right now. (JCS 5/29/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUN 6, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | v| | | | | | | 3/15******************* 967 | | v | | | | | | | 4/1 ***************** 832 | | v| | | | | | | | 4/15*************** 754 | | v | | | | | | | | 5/1 *********** 567 | | v | | | | | | | | 5/15******* 360 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUN 5 v = Heat Units on MAY 30; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Like last year, Pale-Striped Flea Beetles have been present in many area fields this year. Adults bear brown & white longitudinal stripes & readily hop when disturbed. Their preferred food sources are the succulent cotyledon leaves early on & lower leaves later in the season. They have chewing mouthparts that score the upper (most often) & lower surfaces of these leaves without causing holes. Fresh wounds bleed plant sap & scarred tissues turn light brown in time. Flea beetles only rarely attack true leaves while cotyledons are present & attractive. Damage is largely cosmetic & often limited to field edges, though remedial action (incl. advanced irrigations) may be needed when the water-balance of a young stand is jeopardized (6/6/99). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 30 - JUN 5 HIGH LOW HUs DEWPT RAIN Recorded 87 55 109 41 0.24 The warming trend will continue this week. Skies will be mostly clear with 10-20 mph winds from the southwest. Night temperatures will remain below normal and daytime temperatures will be slightly below normal. However, by the end of the week, temperatures will probably exceed 100 F in many locations. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 65% complete at this time. HU last week = 109. Heat Unit accumulation since Jan 1 = 1388. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .62" .39" .26" .22" .22" AGRONOMY UPDATE -------------------------------- It is not at all uncommon to find aborted squares in fields at this time. Causes for square abortion can vary from field to field, but a common factor to consider for many cases at this time are the persistent dry winds that we have experienced. Small plant canopies are somewhat sucseptible to this type of stress and damage to small squares. It is important to encourage plant growth and vigor for many fields at this time. However, with square loss and low FR, plants may also have the tendency to experience rapid increases in vegetative growth. Growers should be alert to changes and patterns in FR and HNRs at this time and be prepared to make appropriate management adjustments. Avoid water stress and adjust N fertilizer and PGR applications. (JCS 6/5/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUN 13, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | |v | | | | | | 3/15********************** 1095 | | | v| | | | | | | 4/1 ******************* 960 | | |v | | | | | | | 4/15****************** 882 | | v | | | | | | | | 5/1 ************** 695 | | v | | | | | | | | 5/15********** 488 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUN 12 v = Heat Units on JUN 6; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- With favorable weather for fruit set & development, it is important to identify causes of square loss. Lygus is our #1 square-feeding insect pest. Especially near non-cotton hosts, the chances of invasion & damage to cotton increases. Sweep net samples are an excellent way to determine the presence & number of Lygus in your field. Because of their patchy distributions, be sure to make at least 4 stops per field; taking at least 25 sweeps per stop. Count the number of nymphs (noting their sizes) & adults per 100 sweeps. Low levels of adult Lygus are normally present in most area fields by now. Action should be taken once there are at least 15-20 total Lygus / 100 sweeps with nymphs present (at least 4-6/100). Earlier action is usually not economical. (pce 6/14/99) WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 6 - JUN 12 HIGH LOW HUs DEWPT RAIN Recorded 96 55 128 36 0.00 This week will begin with highs in the upper 90s to over 100; lows in the upper 60s. Temperatures will warm during the week; most all locations will probably have highs over 100. Some areas could have partly cloudy skies during the afternoon. There is a chance of isolated to scattered thunderstorms in the afternoon around mountains mainly in southeast Arizona. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 77% complete at this time. HU last week = 128. Heat Unit accumulation since Jan 1 = 1516. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .94" .68" .53" .25" .25" AGRONOMY UPDATE -------------------------------- The 1999 University of Arizona Cotton Report and other very interesting cotton related publications are available online at: http:\\ag.arizona.edu\cotton Several crop / pest management workshops are scheduled on the following dates: 17 June - Yuma Co.; Tacna, 12 - 3 p.m. 23 June - Parker / Mohave Valleys 29 June - Pinal Co. (Maricopa Ag. Center) 6 July - Buckeye 8 July - Safford 13 July - Marana Contact local county extension offices for details. (JCS 6/12/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUN 20, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | v | | | | | | 3/15************************* 1264 | | | |v | | | | | | 4/1 *********************** 1129 | | | v | | | | | | 4/15********************* 1051 | | v | | | | | | | 5/1 ***************** 864 | | v | | | | | | | | 5/15************* 657 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUN 19 v = Heat Units on JUN 13; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- With favorable weather for fruit set & development, it is important to identify causes of square loss. Lygus is our #1 square-feeding insect pest. Especially near non-cotton hosts, the chances of invasion & damage to cotton increases. Sweep net samples are an excellent way to determine the presence & number of Lygus in your field. Because of their patchy distributions, be sure to make at least 4 stops per field; taking at least 25 sweeps per stop. Count the number of nymphs (noting their sizes) & adults per 100 sweeps. Low levels of adult Lygus are normally present in most area fields by now. Action should be taken once there are at least 15-20 total Lygus / 100 sweeps with nymphs present (at least 4-6/100). Earlier action is usually not economical. (pce) WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 13 - JUN 19 HIGH LOW HUs DEWPT RAIN Recorded 106 65 168 43 0.00 This week will have highs well over 100; some locations could reach 110+. Lows will be in the 70s to mid 80s. Winds are expected to be light. Early in the week, southeast Arizona will continue to have some scattered afternoon thunderstorms. During the remainder of the week there will be some occasional high clouds but little or no chance of precipitation. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 88% complete at this time. HU last week = 168. Heat Unit accumulation since Jan 1 = 1685. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.24" .98" .83" .47" .25" AGRONOMY UPDATE -------------------------------- Most fields in this area are in pre-bloom stages of development. In many cases flowering may be delayed in relation to HU accumulation due to delayed fruiting and/or abortion of early squares. The next four weeks will be critical to the development and realization of the yield potential for many fields. In general, most fields need to improve crop vigor and retain as much fruit as possible. With hot and dry conditions it is critical to avoid water stress. Good field scouting, insect control, fertilization, and PGR use will also be important to management and realizing the best of the crop's potential. 1999 UA Cotton Reports are available at the Arizona Cotton Information Site, http://ag.arizona.edu/cotton (JCS 6/19/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUN 27, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | |v | | | | | 3/15***************************** 1436 | | | | v| | | | | | 4/1 ************************** 1301 | | | | v | | | | | | 4/15************************ 1223 | | | v| | | | | | | 5/1 ********************* 1036 | | v| | | | | | | | 5/15***************** 829 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUN 26 v = Heat Units on JUN 20; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Lygus eggs develop in about 1 week. There are 5 nymphal instars; the last 2 are most damaging. Instars 1-3 together take about 1 week to develop. Females lay eggs into petioles & leaf blades (esp. near veins). Eggs are concealed within the plant, yet visible as small oval, white caps through which the nymphs emerge. Once adults invade a field & oviposition is confirmed, a new flush of emerging nymphs can be expected in 1 week with the larger, more damaging instars following 1 week later. Chemical controls are best timed according to the appearance (& levels) of nymphs, because insecticides have only limited impact on adults. Action should be taken once there are at least 15-20 total Lygus / 100 sweeps with nymphs present (at least 4-6/100). (pce 6/28/99). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 20 - JUN 26 HIGH LOW HUs DEWPT RAIN Recorded 105 66 172 45 0.00 Mostly sunny & hot with moderate humidity this week. The humidity should decrease by mid-week as dry westerly flow redevelops over AZ. The combination of above normal humidity and hot westerly flow will cause both day & night temperatures to run about 5 degrees above normal this week. Isolated thunder- storms are possible each day, especially near mountains and along the Mexican border. This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 95% complete at this time. HU last week = 172. Heat Unit accumulation since Jan 1 = 1857. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.63" 1.36" 1.21" .83" .42" AGRONOMY UPDATE -------------------------------- Crop conditions statewide have generally improved in the recent weeks with the onset of warm (hot) and dry weather. The next few weeks represent a critical period for cotton fields in all parts of Arizona. The stage of growth for many areas is still behind, relative to normal, but fields have the potential of gaining in crop vigor and fruit retention (FR) at this time. The most critical aspect of crop management is to maintain good irrigation intervals and avoid crop stress. It will also be important to monitor crop condition on a regular basis and watch for shifts in vigor (HNR) and FR. Applications of N can be made with or between irrigations depending on crop condition. Complete N applications by peak bloom. (JCS 6/26/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUL 4, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | v | | | | | 3/15********************************* 1633 | | | | | v | | | | | 4/1 ****************************** 1498 | | | | v | | | | | 4/15**************************** 1420 | | | | v | | | | | | 5/1 ************************* 1233 | | | v| | | | | | | 5/15********************* 1026 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 3 v = Heat Units on JUN 27; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- The most reliable measure of PBW levels is cutting bolls & searching for live larvae. Concentrate search efforts to 1) non-Bt fields, & 2) the earliest planted (& squaring) fields. These fields are at greatest risk for early PBW infestation. Treat non-Bt cotton when 10% bolls have live PBW. Bt cotton should not require sprays for PBW. WFs may be found in many fields via sweepnet. Confirm their ID & start leaf-turn sampling. 3 species may be present: greenhouse (pupae: long hairs; adults: overlapping wings), bandedwinged (darker pupae: short fringe; adults: bands) & sweetpotato (naked pupae; adults: yellow bodies & slightly parted wings). Bandedwinged WFs may still be the most abundant WF species in some fields & generally do not require controls (7/06). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 27 - JUL 3 HIGH LOW HUs DEWPT RAIN Recorded 106 75 196 53 0.00 Monsoon humidity, already in place in southeast AZ, will spread across the state this week, bringing above normal dew points and a significant chance for afternoon and evening thunderstorms. Temperatures should run about 2-3 degrees above normal due to warm night temperatures caused by high humidity and clouds. Expect minimum temperatures to run in the upper 70s and low 80s in low elevation production areas. The atmospheric pattern driving this week's monsoon flow is expected to continue through most of the week. HU last week = 196. Heat Unit accumulation since Jan 1 = 2054. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.09" 1.81" 1.65" 1.26" .83" AGRONOMY UPDATE -------------------------------- Good irrigation management is critical at this time to achieve good crop vigor (height:node ratio,HNR) and fruit retention (FR). Water stress at this stage of the season should be avoided. Patterns in crop vigor (HNR) and FR should be monitored regularly. Plants need to set as many sites as possible, therefore strong growth rates are acceptable, IF the FR levels are also good. If appli- cations of mepiquat chloride are being considered, the best potential for pos- itive yield responses are when HNRs are increasing above the Arizona baselines and FR is dropping. Identify causes of fruit losses. N applications should be completed as the crop goes into peak bloom (approx. 2000 HUAP), based on crop condition (FR and vigor) and previous fertilizer applications. (JCS 7/3/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUL 11, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v | | | | 3/15************************************ 1824 | | | | | v| | | | | 4/1 ********************************** 1689 | | | | | v | | | | | 4/15******************************** 1611 | | | | |v | | | | | 5/1 **************************** 1424 | | | | v | | | | | | 5/15************************ 1217 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 10 v = Heat Units on JUL 4; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Monsoon-associated winds, dust & rain can drastically change pest levels & distributions. Futhermore, low cotton prices demand that pest densities are measured accurately as they change. This ensures proper timing of strategic insecticides like the IGRs for WFs. Sample both adults & nymphs on the 5th mainstem leaf below the terminal; spray when 40% leaves have 3 or more WF adults (12 out of 30 leaves; = 3-5 adults/leaf) AND 40% leaf disks (quarter- size) have 1 or more large visible nymphs (12 out of 30 disks; = 1 large nymph/disk). Research has shown that strong monsoons can reduce even WF egg & nymph populations significantly, but after a rain, do NOT sample WF adults; these numbers are unreliable. Cut bolls now for PBW levels (pce 7/12/99). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 4 - JUL 10 HIGH LOW HUs DEWPT RAIN Recorded 102 74 192 63 0.89 The monsoon is forecast to be less active this week due to a less favorable circulation pattern. Dew points should be lower this week; however, isolated thunderstorms are possible each day, especially near the mountains. Expect temperatures to run about normal for the week. Intense monsoon flow brought very humid air to much of AZ last week. The high humidity fueled an abundance of rainfall in many locations and above normal night temperatures. Fortunately, daytime temperatures were below normal last week, helping to lessen the potential for heat stress. HU last week = 192. Heat Unit accumulation since Jan 1 = 2245. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.96" 1.74" 1.62" 1.31" .97" AGRONOMY UPDATE -------------------------------- With the increasing humidity and night temps that are common with the mon- soon season in Arizona, we often experience decreases in fruit retention (FR), particularly from the abortion of young (1 to 5 day old bolls), and increases in vegetative growth (HNR). It is important to monitor and identify growth trends with distinct decreases in FR and increases in HNRs. If applications of mepiquat chloride are being considered, the best probability for a positive yield response is when HNRs begin to move above the middle baselines described for AZ cotton, and FR is also dropping. Under these circumstances, N fertil- izer should be managed conservatively. Bulletins describing crop management (e.g. PIXtm and N) are avail. http://ag.arizona.edu/cotton (JCS 7/10/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUL 18, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v | | | | 3/15**************************************** 2019 | | | | | | v | | | | 4/1 ************************************** 1884 | | | | | |v | | | | 4/15************************************ 1806 | | | | | v | | | | | 5/1 ******************************** 1619 | | | | v | | | | | 5/15**************************** 1412 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 17 v = Heat Units on JUL 11; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Bt cotton should not require sprays for PBW. Non-Bt cotton requires intensive scouting for spray decisions. 1999 is a high-risk year for PBW problems. The winter was very dry which contributes to overwintering success & delayed emergence of moths. Heavy monsoons which contribute to warm, humid nights are also conducive to PBW survival & reproduction. Couple this with delayed & slow crop development which extends our cotton season & we have ideal PBW conditions. Spray decisions depend 1st on the detection & level of small larvae in bolls & 2nd on timing of moth flights monitored by in-field PBW traps. Nighttime sprays are most effective & may be made every 5 days for 3 sprays once 10% bolls infested with larvae & traps show a flight (pce 7/19). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 11 - JUL 17 HIGH LOW HUs DEWPT RAIN Recorded 100 75 195 68 0.14 The high humidity and monsoon pattern will continue this week. Scattered thunderstorms in the afternoon and evening are expected. Some areas could experience rain in the morning hours. Most locations will have high temperatures in the mid-90s with lows in the 70s. However, lower desert areas could have highs above 100. This advisory is available on the Internet at: http://ag.arizona.edu/azmet HU last week = 195. Heat Unit accumulation since Jan 1 = 2440. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.93" 1.74" 1.63" 1.38" 1.09" AGRONOMY UPDATE -------------------------------- The abortion of small (one to three day old) bolls has increased as expected in the past two to three weeks. The primary cause for the abortion of small one to five day old bolls is related to the weather conditions and heat stress levels that have increased recently (heat,higher humidity, etc.). When a loss of squares are noted, primary causes to consider include water stress or insect damage. It is important to identify and make note of changes in fruit retention and crop vigor (height to node ratios). Soils should be monitored to determine the actual benefit to plant-available water from recent rains. The UA cotton advisories for all locations can be obtained on the internet at the Arizona Cotton Information Site http://ag.arizona.edu/cotton (JCS 7/17/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY JUL 25, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v| | | | 3/15******************************************** 2216 | | | | | | v | | | | 4/1 ****************************************** 2081 | | | | | | v | | | | 4/15**************************************** 2003 | | | | | |v | | | | 5/1 ************************************ 1816 | | | | | v | | | | | 5/15******************************** 1609 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 24 v = Heat Units on JUL 18; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Resistance is a fundamental risk associated with use of any pesticidal product, sprayable, transgenic, or inbred. Some factors associated with risk are frequency & intensity of use, & relative abundance of susceptible & resistance individuals. Consequences of these resistances may be drastic (pesticidal field failure), subtle (the need for increased rates or frequency), or inconsequential (pest control system unaffected). Basic steps for avoiding/mitigating resistances include maximizing all avoidance tactics, using products ONLY when & at the rates necessary to do the job, & rotating among dissimilar active ingredients. To learn more about pest resistances, attend a short course offered by Cooperative Extension in Phoenix (8/12 & 19) WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 18 - JUL 24 HIGH LOW HUs DEWPT RAIN Recorded 104 76 196 59 0.00 Atmospheric circulation will continue to support monsoon flow this week. Warm & humid weather will continue all week & showers/thunderstorms are possible each day. Forecasted circulation patterns should allow one or more tropical disturbances (easterly waves) to move across AZ this week, enhancing the chances for widespread and/or heavy rains. The first of these disturbances is forecast to enter SE AZ on Tuesday; passage of a second disturbance is possible on Thursday or Friday. Radar & satellite images are available from National Weather Service (NWS) web pages. AZMET provides links to NWS web pages at http://ag.arizona.edu/azmet. HU last week = 196. Heat Unit accumulation since Jan 1 = 2637. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.61" 2.61" 2.51" 2.17" 1.79" AGRONOMY UPDATE -------------------------------- Evaluating stage of growth is very important in terms of many management deci- sions. An easy and accurate technique for determing the stage of growth in a field is to count the number of nodes above the top (first position) white flower (NAWF) on the mainstem of the plant. At first bloom, we would like to see 9-11 NAWF (approx. 1200 HUAP). At peak bloom plants should have 6-8 NAWF (approx. 2000 HUAP). When the NAWF counts drop to 5 or less this is a good indication that the crop is rapidly progressing into cut-out. Crop progression through the fruiting cycle will also depend on other factors such as fruit re- tention (FR), vigor (HNR), and any stress factors the plant has experienced. If FR is low, crop maturity can be significantly delayed. (JCS 7/24/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY AUG 1, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v | | | 3/15************************************************ 2403 | | | | | | |v | | | 4/1 ********************************************* 2268 | | | | | | v| | | | 4/15******************************************** 2190 | | | | | | v | | | | 5/1 **************************************** 2003 | | | | | |v | | | | 5/15************************************ 1796 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 31 v = Heat Units on JUL 25; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Various regions of the world have felt the impact of a reputation for 'sticky' cotton, a situation AZ can ill afford. Economic impact of various stickiness' to producers in the U.S. range from $0.03-0.05 / lb of lint regardless of its actual quality. These losses affect whole regions & often last more than the current marketing season. This is why every producer must consider seriously the impact of whiteflies (or aphids) on their lint. The UA has excellent guidelines for timing both IGR & conventional insecticides for WF control. Key to their proper use is careful & systematic sampling & adherence to timing guidelines. Full use of these procedures is most needed as decisions draw closer. Visit ag.arizona.edu/cotton for more information. WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 25 - JUL 31 HIGH LOW HUs DEWPT RAIN Recorded 98 73 186 66 0.36 Monsoon flow will return Monday, replacing the brief weekend dry spell. In contrast to recent monsoon weather, temperatures this week will run at or above normal in most locations. Scattered thunderstorms are possible each day, with the best chance of rain expected late in the week. The summer of 1999 has produced one of the coolest and most humid July's on record. Above normal precipitation was also recorded at many locations. As a result, heat stress has been less of a problem for the 1999 crop. A summary of July weather will be distributed next week. HU last week = 186. Heat Unit accumulation since Jan 1 = 2824. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.82" 1.82" 1.82" 1.75" 1.49" AGRONOMY UPDATE -------------------------------- Evaluating fields on a regular basis is very important at this stage of crop development and the conditions that we are experiencing. A common cause for fruit abortion at this time can often be related to the prevailing weather conditions (warm and humid/high dewpoint temps.) resulting in the abortion of small 1 to 5 day old bolls. Lygus infestations and water stress can also contribute to square abortion. For crop management, water stress should be avoided in all cases (stress can compound FR problems), fertilizer N applica- ions should be managed conservatively and completed by peak bloom. Mepiquat chloride (MC) applications may be considered if crop vigor is increasing. If MC applications are considered, refer to UA PIXtm guidelines).(JCS 7/31/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY AUG 8, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v | | | 3/15**************************************************** 2594 | | | | | | | v | | | 4/1 ************************************************* 2459 | | | | | | | v | | | 4/15************************************************ 2381 | | | | | | v| | | | 5/1 ******************************************** 2194 | | | | | | v | | | | 5/15**************************************** 1987 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to AUG 7 v = Heat Units on AUG 1; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Various regions of the world have felt the impact of a reputation for 'sticky' cotton, a situation AZ can ill afford. Economic impact of various stickiness' to producers in the U.S. range from $0.03-0.05 / lb of lint regardless of its actual quality. These losses affect whole regions & often last more than the current marketing season. This is why every producer must consider seriously the impact of whiteflies (or aphids) on their lint. The UA has excellent guidelines for timing both IGR & conventional insecticides for WF control. Key to their proper use is careful & systematic sampling & adherence to timing guidelines. Full use of these procedures is most needed as decisions draw closer. Visit ag.arizona.edu/cotton for more information. WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 1 - AUG 7 HIGH LOW HUs DEWPT RAIN Recorded 104 73 191 50 0.00 Sunny, warm & less humid this week. Movement of a Pacific low pressure trough should bring drier southwesterly flow to most of the region by Tuesday or Wednesday. This drier flow should lower dew points which will produce hotter days, but a continuation of cooler nights. The best chance for precipitation is Monday & Tuesday in east central & southeast production areas. Maximum temperatures in July were the coolest in more than 15 years. Precipitation totals were at or above 1990 levels at most locations. HU last week = 191. Heat Unit accumulation since Jan 1 = 3015. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.7" 2.7" 2.7" 2.7" 2.57" AGRONOMY UPDATE -------------------------------- Fields normally show signs of progressing into cut-out by the time about 2500 heat units after planting (HUAP) have been accumulated. Plant progression through the fruiting cycle can be monitored by the number of nodes above the (first position) top white flower (NAWF). When the NAWF is about 7-8, the crop is in peak bloom. When the NAWF is 5 or less the crop is rapidly progressing toward cut-out. At peak bloom, fruit retention (FR) levels should be about 70% (considering the first 2 fruiting sites on each fruiting branch). As the crop goes into cut-out FR levels should be about 50%. Low FR levels can contribute to delayed maturity. It is important to monitor field conditions. Boll counts of 15-20 bolls/ft. estimate about 1 bale/acre yield potential. (JCS 8/7/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY AUG 15, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v| | | 3/15******************************************************* 2764 | | | | | | | v | | | 4/1 ***************************************************** 2629 | | | | | | | v | | | 4/15*************************************************** 2551 | | | | | | | v | | | 5/1 *********************************************** 2364 | | | | | | v| | | | 5/15******************************************* 2157 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to AUG 14 v = Heat Units on AUG 8; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- A poor economic climate for cotton can be made worse by inappropriate late season pest management decisions. It is important now to evaluate your potential production & estimate when your crop stops being susceptible to insect damage. This point in time will differ for each pest & even by variety (e.g., Bt cotton). Foliar pests diminish in importance as you reach cut-out, except for severe infestations that might interfere with defoliation. Square- feeding pests (e.g., Lygus) also diminish in importance except where substantial late production is the goal. Boll-attacking pests (esp. PBW) must be monitored & controlled past cut-out. Control of quality-reducing pests (aphids & WFs), however, REQUIRES vigilance until green-leaf drop (pce 8/16). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 8 - AUG 14 HIGH LOW HUs DEWPT RAIN Recorded 102 66 170 42 0.00 The atmospheric features that drive the monsoon will remain in place this week. Expect typical warm & humid conditions with scattered afternoon thunderstorms. The more widespread rainfall should occur in central & southeastern production areas. Rain activity is expected to peak on Monday & then again late in the week (Thursday on). Some drying along with higher temperatures is expected Tuesday & Wednesday. Temperatures are expected to run near normal. Longer term, the monsoon shows no sign of ending. Current forecasts call for the humidity and rains to continue through at least next week. HU last week = 170. Heat Unit accumulation since Jan 1 = 3185. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.45" 2.45" 2.45" 2.45" 2.45" AGRONOMY UPDATE -------------------------------- Many fields are somewhat delayed this season in terms of stage of growth. In some cases this is due to poor fruit retention. When the number of nodes above the top (1st position) white flower (NAWF) is 7-8 the crop is still in peak bloom and has a considerable amount of fruiting potential remaining. When the NAWF is 5 or less the plant is progressing towards cut-out which is a good time to evaluate crop condition and decide on the final irrigations. If fruit reten- tion is about 50% at NAWF 5 or less, and plants have about 25 fruiting branches, the crop should have good yield potential. Boll counts can be used to estimate yield potential. About 20 bolls/ft. equate to a 1 bale/acre yield potential (36-40 in. rows). (JCS 8/14/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY AUG 22, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15*********************************************************** 2964 | | | | | | | v | | 4/1 ********************************************************* 2829 | | | | | | | v | | | 4/15******************************************************* 2751 | | | | | | | v | | | 5/1 *************************************************** 2564 | | | | | | | v | | | 5/15*********************************************** 2357 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to AUG 21 v = Heat Units on AUG 15; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- Where Bt cotton is grown, termination decisions can drastically affect the utility of refugia for resistance prevention. Refugia (non-Bt cotton) are required in order to produce susceptible PBW moths capable of mating with any potentially resistant moths emerging from Bt fields. To be successful, non-Bt refugia must be present & producing moths for the full period that Bt cotton is grown. E.g., if the season is extended for Bt cotton through additional irrigations, then the refugia, too, should be extended. Earlier termination of refugia cotton will only serve to remove the benefits of growing it all season long. PBW levels are highest late in the season, & it is during this period when production of moths from refugia is most important (pce 8/23). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 15 - AUG 21 HIGH LOW HUs DEWPT RAIN Recorded 106 77 200 60 0.27 Atmospheric circulation patterns are expected to sustain monsoon flow much of this week. Mostly sunny & hot Monday with increasing humidity. Higher humidity mid-week will lower daytime temperatures some and bring an increase in thunder- storm activity. Temperatures should run a few degrees above normal this week. Note! Some forecast models suggest remnants of Hurricane Bret may move through AZ later in the week, providing the chance for more widespread precipitation. HU last week = 200. Heat Unit accumulation since Jan 1 = 3385. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.29" 2.29" 2.29" 2.29" 2.29" AGRONOMY UPDATE -------------------------------- Cut-out can easily be determined when the number of nodes above the top, first position flower (NAWF) averages 5 or less. Many varieties will show signs of cut-out and have open bolls with about 2500 HUAP. Fields with poor fruit re- tention (FR) are somewhat delayed in their completion of the first fruiting cycle. In some cases prolific square production at the top of the plant is being considered for full development. New squares will require 2-3 weeks to form a bloom, a bloom will then need at least 3 weeks to develop into a full- sized, hard, green boll, and then 2 more weeks to open. Thus, new squares will require at least 8 weeks of development to be a harvestable boll. Costs vs. yield potential have to be considered very carefully. (JCS 8/21/99) HARQUAHALA COTTON DEVELOPMENT ADVISORY AUG 29, 1999 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15*************************************************************** 3164 | | | | | | | | v | | 4/1 ************************************************************* 3029 | | | | | | | | v | | 4/15*********************************************************** 2951 | | | | | | | v | | | 5/1 ******************************************************* 2764 | | | | | | | v | | | 5/15*************************************************** 2557 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to AUG 28 v = Heat Units on AUG 22; S,M,F = Short, Medium, and Full Season Varieties INSECT UPDATE -------------------------------- WF numbers may ostensibly decline in fields that are in or near cut-out. However, re-growth after cut-out can lead to new leaves ideal for hosting large numbers of WFs. Excessive foliage may also occur where fruit retention levels are low. Growers should monitor WF adults & nymphs in order to assess the need for control. When 5 adults / leaf (57% leaves infested > 2 adults) are present, control may still be necessary to prevent stickiness. If > 30 days are expected before green-leaf drop (& other pest levels are low), an IGR may still be indicated & economical. If the duration needed is shorter &/or adult levels are high (> 10 / leaf) & other pests require control, then conventional chemistry may be a more efficient/economical choice (pce 8/30). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 22 - AUG 28 HIGH LOW HUs DEWPT RAIN Recorded 107 76 200 62 0.34 Mostly sunny, warm and humid through mid-week with a chance of afternoon thunderstorms each day. An upper level trough of low pressure is expected to move out of California by mid-week which should lower humidity levels, lessen the chances for precipitation and raise temperatures. Expect temperatures to average a few degrees above normal for the week. HU last week = 200. Heat Unit accumulation since Jan 1 = 3585. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.2" 2.29" 2.29" 2.29" 2.29" AGRONOMY UPDATE -------------------------------- As the final management steps are taken with the 1999 cotton crop and fields are defoliated, it is important to recognize a number of factors that serve to impact defoliation efforts. The chemical defoliant is always a common point of focus. However, factors such as: 1) plant-water status and 2) N fertility sta- tus at the time of defoliation; 3) weather conditions; and 4) the conditions of the leaves also serve to impact the effectiveness of a defoliant applica- tion. Therefore, it is important to take all of these factors into considera- when making a defoliant application or evaluating the results from one. More information is available on the internet at the Arizona Cotton Information Site (ACIS). The web site is http://ag.arizona.edu/cotton (JCS 8/28/99) THIS IS THE FINAL COTTON ADVISORY FOR 1999. HAVE A SAFE HARVEST SEASON ! HARQUAHALA COTTON DEVELOPMENT ADVISORY JUL 30, 2000 PLANTING DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v | | | 3/15****************************************************** 2724 | | | | | | | v | | | 4/1 **************************************************** 2577 | | | | | | | v | | | 4/15************************************************ 2375 | | | | | | v | | | | 5/1 ******************************************* 2134 | | | | | | v | | | | 5/15************************************** 1880 | | | | | | | | | | | Pin Sus 1st 1" Pk. Bloom Cut-Out Terminate | | head Sq. Flowr Boll +---+---+ +---+---+ +---+---+ | | S M F S M F S M F | +-------+-------+-------+-------+-------+-------+-------+-------+-------+-+ 0 400 800 1200 1600 2000 2400 2800 3200 3600 HEAT UNITS ACCUMULATED FROM PLANTING to JUL 29 v = Heat Units on JUL 22; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Even with Bt cotton dominating the AZ landscape, it is important to monitor PBW activity (traps & bolls). Traps should be placed inside of fields at or just above canopy height. Windy nights can lower trap catches, but traps do serve as an indicator of general moth activity. A moth, unrelated to cotton production or PBW, with black & white stripes may be found in area traps. Traps cannot replace boll-cutting as a management guide. Scouts should target non-Bt, early planted fields for the majority of their boll-cutting efforts. Once PBW are detected there, more general surveys of all fields including Bt may be necessary. Treat non-Bt fields once there is at least 10% bolls with live larvae & traps indicate moth activity in the area (pce 7/31). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 23 - JUL 29 HIGH LOW HUs DEWPT RAIN Recorded 110 78 204 57 0.00 Mostly sunny & hot with moderate humidity this week. Scattered thunderstorms are possible each day, especially near high elevation areas. Temperatures are expected to run about 3 degrees above normal for the week. Last week's hot temperatures & moderate humidity generated a rather stressful week for cotton growing in central & western AZ. Data from local AZMET stations indicates last week was the most difficult week to date for heat stress. More information on heat stress is on the web at http://ag.arizona.edu/azmet. Click on button labeled Cotton Advisories & scroll down to section containing location specific heat stress reports. Then click on location of interest. HU last week = 204. Heat Unit accumulation since Jan 1 = 3131. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.75" 2.75" 2.75" 2.75" 2.44" AGRONOMY UPDATE -------------------------------- The development of cotton bolls is reasonably predicable based on heat unit (HU) accumulations. For boll development to progress from a flower to a full- sized, hard green boll, approximately 600 HU are required. The accumulation of 600 HUs in most parts of Arizona at this time of the season generally equates to about 3 weeks (21 days). It is in the later portions of this stage in boll development when secondary wall development is taking place which leads to the fiber thickness, measured in micronaire. Boll maturity can be checked by cut- ting into the boll with a sharp knife (safety first!). Bolls are mature if seed coats are tan or brown and the seed embryos show tiny folded leaves. With a uniform fruit set it is important to monitor boll development. (JCS 7/30/00)