ELOY FEB 27, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | **************** | ****** 324 ***** | **************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - FEB 26 v = Heat Units accumulated from JAN 1 - FEB 19 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Fields suspected of having Root-knot nematode can be sampled now, but assays may be difficult because of the lack of winter rain. Many fields are dry below the plow layer, and for best results, samples should be taken from soil with some moisture. Growers are encouraged to send samples for analysis free of charge to UA Dept of Plant Pathology ( http://Ag.Arizona.Edu/PLP/plpext/ ). Fields with detectable levels should be considered for pre-plant fumigation with Telone. Optimum conditions for fumigant 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. (mo 2/21/00). WEATHER UPDATE -------------------------------- Last Week : FEB 20 - FEB 26 This Week : FEB 27 - MAR 4 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 71 40 34 40 ---- Normal 72 43 37 44 Recorded 70 41 36 37 0.16 1999 70 37 35 35 HUs are running about 12 days ahead of normal. FORECAST: The subtropical jet stream will be positioned over AZ this week, bringing unsettled weather. Storm systems are expected to pass along the jet on Monday, Wednesday and Friday. Each system will bring increased cloudiness, winds and a chance for scattered showers. Temperatures will fluctuate with the passing of storms, but none of the storms is expected to be exceptionally cold. Expect temperatures to run about normal for the week. Soils typically warm to acceptable levels for germination when lows are 48F and above and highs exceed 80F. It is especially important to monitor soil temperatures and the 5-day forecast when planting early. Last Week's 8am Soil Temp: Max = 58.1 FEB 21 ; Min = 48.6 FEB 26 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. Recent weather patterns have provided cooler, more seasonal temperatures. There have even been a few reports of rain in southern AZ recently. Planting varieties with low seedling vigor should be done with caution early in the season. 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 2/26/00). ELOY MAR 5, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ******************* | ******** 375 ****** | ******************* | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 4 v = Heat Units accumulated from JAN 1 - FEB 26 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Fields suspected of having Root-knot nematode can be sampled now, but assays may be difficult because of the lack of winter rain. Many fields are dry below the plow layer, and for best results, samples should be taken from soil with some moisture. Growers are encouraged to send samples for analysis free of charge to UA Dept of Plant Pathology ( http://Ag.Arizona.Edu/PLP/plpext/ ). Fields with detectable levels should be considered for pre-plant fumigation with Telone. Optimum conditions for fumigant 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. (mo 2/21/00). WEATHER UPDATE -------------------------------- Last Week : FEB 27 - MAR 4 This Week : MAR 5 - MAR 11 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 72 43 37 44 ---- Normal 74 41 34 47 Recorded 76 40 27 50 0.03 1999 73 37 37 45 HUs are running about 12 days ahead of normal. FORECAST: Scattered showers will be prevalent early this week. Highs in most areas will only reach the mid 60s; lows could drop into the upper 30s. Chance of showers will continue throughout the week. Highs during the later part of the week might reach the low 70s; lows could be in the low 40s to the low 50s. Expect temperatures to run below normal for the week. Soils typically warm to acceptable levels for germination when lows are 48F and above and highs exceed 80F. It is especially important to monitor soil temperatures and the 5-day forecast when planting early. Last Week's 8am Soil Temp: Max = 56.5 FEB 28 ; Min = 49.5 FEB 27 AGRONOMY UPDATE -------------------------------- It is important to monitor soil temperatures at the depth of planting and to watch the weather forecast (5 day). Cottonseed planted in soils with tempera- tures below 55 F has a high probability of experiencing poor germination rates, seedling disease, and a poor stand. When planting into dry soil and watering-up, it is important to recognize that the beds will be cooled consid- erably following the first irrigation. Recent studies have shown us exactly what Paul Brown has been saying for many years, that wet-planted soil tempera- tures at the seedline follow air temperatures very closely and as a result can have large temperature shifts everyday with relatively cool average tempera- tures as well. UA cotton website http://ag.arizona.edu/cotton (JCS 3/04/2000) ELOY MAR 12, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ******************** | ******** 397 ******* | ******************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 11 v = Heat Units accumulated from JAN 1 - MAR 4 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Fields suspected of having Root-knot nematode can be sampled now, but assays may be difficult because of the lack of winter rain. Many fields are dry below the plow layer, and for best results, samples should be taken from soil with some moisture. Growers are encouraged to send samples for analysis free of charge to UA Dept of Plant Pathology ( http://Ag.Arizona.Edu/PLP/plpext/ ). Fields with detectable levels should be considered for pre-plant fumigation with Telone. Optimum conditions for fumigant 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. (mo 2/21/00). WEATHER UPDATE -------------------------------- Last Week : MAR 5 - MAR 11 This Week : MAR 12 - MAR 18 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 74 41 34 47 ---- Normal 78 45 37 65 Recorded 65 41 43 23 1.28 1999 70 45 46 37 HUs are running about 7 days ahead of normal. FORECAST: High pressure will reside over Arizona most of the week. Expect mostly sunny, dry and mild weather this week. Temperatures should average ~3F above normal. Low soil temperature can slow germination & result in poor stand establishment. It is best to plant when soil temperatures are expected to remain above 60F for the entire 24-hour day. Standard weather forecasts of air temperature can serve as a guide for planting because air temperature & soil temperature at planting depth are closely linked. Soil temperatures remain near acceptable levels if minimum air temperatures run 48F or higher and highs exceed 80F. Thus, a good planting forecast: clear & dry with lows in upper 40s and highs above 80F. Last Week's 8am Soil Temp: Max = 56.5 MAR 5 ; Min = 46.2 MAR 8 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 to absorb (imbibe) water and initiate a rapid increase in metabolic activity. Much of this physiological activity on the part of the seed takes place within the first few hours after planting. It is at this stage when a young seedling is very sensitive to chilling injury. If soil temperatures are 50 F or less while the seed is first imbibing water, severe damage to the seedling can occur, which can negatively affect vigor and enhance the chances for seedling diseases. The cotton advisories and other UA cotton related info. can be accessed at http://ag.arizona.edu/cotton (JCS 3/11/00) ELOY MAR 19, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ************************ | ********** 477 ********* | ************************ | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 18 v = Heat Units accumulated from JAN 1 - MAR 11 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square PLANTING INFORMATION -------------------------------- Low soil temperature can slow germination & result in poor stand establishment. It is best to plant when soil temperatures are expected to remain above 60F for the entire 24-hour day. Standard weather forecasts of air temperature can serve as a guide for planting because air temperature & soil temperature at planting depth are closely linked. Soil temperatures remain near acceptable levels if minimum air temperatures run 48F or higher and highs exceed 80F. Thus, a good planting forecast: clear & dry with lows in upper 40s and highs above 80F. WEATHER UPDATE -------------------------------- Last Week : MAR 12 - MAR 18 This Week : MAR 19 - MAR 25 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 78 45 37 65 ---- Normal 78 46 36 65 Recorded 82 48 37 80 0.00 1999 79 46 41 69 HUs are running about 9 days ahead of normal. FORECAST: A strong winter storm will pass through northern AZ and into Texas early this week. Expect windy & much cooler weather through mid-week, with a chance for showers Monday & Tuesday. The best chance for rain is in central & southeast production areas. A warming trend will begin on Wednesday & temperatures should return to normal by late in the week. Temperatures will average about 3-5 degrees below normal for the week. Cotton planted early this week may be subjected to cold soil temperatures and rain. Growers should consider delaying and/or halting planting until warmer weather returns and the 5-day forecast improves. Last Week's 8am Soil Temp: Max = 58.3 MAR 17 ; Min = 51.3 MAR 12 AGRONOMY UPDATE -------------------------------- Several factors can impact cotton germination and emergence such as: tempera- tures, soil crusting, depth of seed placement, salinity, and herbicide place- ment. Cotton is a relatively salt tolerant crop, but during germination and emergence, seedlings can be effected by salt concentrations that would not hurt larger plants. For example, salt concentrations resulting in soil elec- trical conductivities (EC) of 5 mmhos/cm (dS/m) in the zone of seed placement can reduce germination and seedling vigor. This can be critical if other fac- tors such as soil temperatures, seedling vigor, etc. are marginal. Every row irrigation will accumulate salts in the middle of the bed. Alternate row ir- rigations can move salts past the seedline. (JCS 3/18/00) ELOY MAR 26, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ************************** | *********** 529 ********** | ************************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - MAR 25 v = Heat Units accumulated from JAN 1 - MAR 18 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square PLANTING INFORMATION -------------------------------- Low soil temperature can slow germination & result in poor stand establishment. It is best to plant when soil temperatures are expected to remain above 60F for the entire 24-hour day. Standard weather forecasts of air temperature can serve as a guide for planting because air temperature & soil temperature at planting depth are closely linked. Soil temperatures remain near acceptable levels if minimum air temperatures run 48F or higher and highs exceed 80F. Thus, a good planting forecast: clear & dry with lows in upper 40s and highs above 80F. WEATHER UPDATE -------------------------------- Last Week : MAR 19 - MAR 25 This Week : MAR 26 - APR 1 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 78 46 36 65 ---- Normal 75 44 36 55 Recorded 75 42 29 53 0.00 1999 63 39 43 18 HUs are running about 8 days ahead of normal. FORECAST: A Pacific storm system will move across AZ early in the week, bringing a chance for rain on Monday & Tuesday. Temperatures will run above normal Monday, then cool to below normal on Tuesday. Temperatures should return to normal for the rest of the week; however, current long range forecasts indicate another weather disturbance may develop late in the week, bringing another chance for showers in central & eastern production areas. Cotton advisories and AZMET data are available on the Internet at the address: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 61.2 MAR 20 ; Min = 52.2 MAR 22 AGRONOMY UPDATE -------------------------------- When selecting a variety and managing for its optimum planting and establish- ment, consider the general seedling vigor that is common to that variety. It is important not to plant varieties that are known to have less than optimal seedling vigor in conditions with cool soil temperatures and/or an unfavorable 5-day forecast. For varieties that are known to have potential limitations with respect to seedling vigor,it is important to try to place the seed in warm soil (65 F or greater at seeding depth) with a favorable 5-day weather forecast. Do not plant these varieties too deep (usually less than 2 inches is best). In general, early plantings should be avoided with varieties with known or expected poor seedling vigor. (JCS 3/25/00) ELOY APR 2, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ***************************** | ************ 585 ************ | ***************************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 1 v = Heat Units accumulated from JAN 1 - MAR 25 * 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. 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. To learn more about 'MAXIMIZING BENEFITS FROM BT COTTON IN ARIZONA' attend one of the ACGA-sponsored programs this week in Maricopa (@ MAC, April 4) or Buckeye (@ VFW Lodge, April 5) (pe 4/00). WEATHER UPDATE -------------------------------- Last Week : MAR 26 - APR 1 This Week : APR 2 - APR 8 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 75 44 36 55 ---- Normal 81 47 34 76 Recorded 75 46 40 56 0.08 1999 73 39 39 45 HUs are running about 7 days ahead of normal. FORECAST: High pressure will reside over AZ this week, bringing clear & dry weather with above normal temperatures. Expect temperatures to run about 5 degrees above normal this week. Long range forecasts indicate a weather disturbance will pass north of AZ on Thursday & bring slightly cooler (but dry) weather by Friday. This cotton advisory is available each Monday at noon via the Internet at: http://ag.arizona.edu/azmet Last Week's 8am Soil Temp: Max = 62.2 MAR 28 ; Min = 56.1 APR 1 AGRONOMY UPDATE -------------------------------- Earliness is becoming increasingly important to cotton production across Arizona. In western and central AZ, earliness is important as a cultural man- agement tool in dealing with many insect pest populations, avoiding late season humidity and heat stress, and also to rotate land with vegetable crops. At higher elevations, earliness is critical due to limitations in the avail- able growing season. Achieving earliness begins with planting and stand estab- lishment. Everything we can do to help maintain a vigorous and healthy stand at the early stages of the season will contribute to beginning and completing a fruiting cycle for yield and quality (micronaire). It is important to match varieties (vigor & maturity) with soil and HU conditions. (JCS 4/1/00) ELOY APR 9, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | ********************************** | *************** 685 ************** | ********************************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 8 v = Heat Units accumulated from JAN 1 - APR 1 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square INSECT UPDATE -------------------------------- Seedling disease can usually be prevented by planting when soils are at least 65oF @ 6-8 inch depth, by using quality seed that emerges and 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: PCNB for Rhizoctonia & triadimenol for Thielaviopsis with systemics (carboxin, chloroneb) & protectants (Thiram, Captan). Fungicides active against Pythium usually are not necessary. However, metalaxyl as part of standard seed treatment is good insurance for areas where Pythium has been identified. In-furrow applications of appropriate fungicides should be used for replant IF disease has been confirmed & the causal agent identified (mo 4/00). WEATHER UPDATE -------------------------------- Last Week : APR 2 - APR 8 This Week : APR 9 - APR 15 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 81 47 34 76 ---- Normal 83 47 30 83 Recorded 88 49 33 100 0.00 1999 72 39 36 41 HUs are running about 9 days ahead of normal. FORECAST: A dry storm system will pass over AZ Monday. Expect mostly sunny, warm & windy conditions Monday followed by slightly cooler weather mid-week. Warm temperatures should return late in the week. Current long-range forecasts show a storm system impacting California during the weekend. This storm system is not projected to drop into AZ; however, growers should obtain an updated forecast before planting late this week. Weekly temperatures should average 3-5 F above normal. Full season varieties perform best when planted before HU accumulation exceeds 700. Medium maturity varieties should be planted before HU accumulation exceeds 800. See graph at the top of page for HU accumulation at your location. Last Week's 8am Soil Temp: Max = 66 APR 6 ; Min = 55 APR 2 AGRONOMY UPDATE -------------------------------- In general, early plantings across the state have resulted in strong and healthy stands. It is important to inspect young seedlings, both above and below ground, in an attempt to evaluate overall health and vigor. The hypo- cotyl 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 brown discoloration in this area due to soil salinity, drying, or abrasions (which can occur at the soil line with wind whipping). Tap roots should be extending 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. (JCS 4/7/00) ELOY APR 16, 2000 COTTON PLANTING DATE ADVISORY +-------------------------------------------------------------------------+ | PINK BOLLWORM SUSCEPTIBILITY * | +---------+------------+-----------------------------------------+ | | HIGH | MEDIUM | LOW | | | v | **************************************** | ****************** 794 ***************** | **************************************** | | ^ normal | | PLANTING WINDOWS | | | Short Season ---------------| | | | Medium Season ----| | | | Full Season | | +---------+---------+---------+---------+---------+---------+---------+---+ 0 200 400 600 800 1000 1200 1400 HEAT UNITS (HU) ACCUMULATED FROM JAN 1 - APR 15 v = Heat Units accumulated from JAN 1 - APR 8 * HIGH:>50%, MEDIUM:25-50%, LOW<25% Spring Emergence after Susceptible Square PEST MANAGEMENT UPDATE ----------------------------------- Seedling disease can usually be prevented by planting when soils are at least 65oF @ 6-8 inch depth, by using quality seed that emerges and 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: PCNB for Rhizoctonia & triadimenol for Thielaviopsis with systemics (carboxin, chloroneb) & protectants (Thiram, Captan). Fungicides active against Pythium usually are not necessary. However, metalaxyl as part of standard seed treatment is good insurance for areas where Pythium has been identified. In-furrow applications of appropriate fungicides should be used for replant IF disease has been confirmed & the causal agent identified (mo 4/00). WEATHER UPDATE -------------------------------- Last Week : APR 9 - APR 15 This Week : APR 16 - APR 22 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 83 47 30 83 ---- Normal 87 50 32 98 Recorded 89 53 32 110 0.00 1999 90 46 34 100 HUs are running about 9 days ahead of normal. FORECAST: A branch of the jet stream will wobble over AZ this week, bringing less settled weather. Partly cloudy, windy & warm Monday. Cloudy, windy & cooler Tuesday with a chance for showers. Clear & mild Wednesday followed by gradual warming through Friday. Another storm system may bring a chance for showers by Friday & Saturday. This week's weather pattern is not a particularly cold one; expect temperatures to average about 2 degrees above normal for the week. Full season varieties perform best when planted before HU accumulation exceeds 700. Medium maturity varieties should be planted before HU accumulation exceeds 800. See graph at the top of page for HU accumulation at your location. Last Week's 8am Soil Temp: Max = 68.5 APR 14 ; Min = 66 APR 11 AGRONOMY UPDATE -------------------------------- Evaluating stand populations and plant conditions is important to early season crop management. 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 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 extending rapidly at early stages of growth at a rate of about 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. (JCS 4/15/00) ELOY COTTON DEVELOPMENT ADVISORY APR 30, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15*********** 573 +4 days | v | | | | | | | | 4/1 ********* 433 +5 days |v | | | | | | | | 4/15***** 226 +1 day | | | | | | | | | | 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 APR 29 v = Heat Units on APR 22; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT 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 5/1). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : APR 23 - APR 29 This Week : APR 30 - MAY 6 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 88 52 32 103 ---- Normal 90 54 32 115 Recorded 94 55 34 126 0.00 1998 88 50 34 99 Warm, high pressure will again dominate AZ weather this week. Expect sunny & mild weather Monday followed by a rapid mid-week warming trend. Temperatures will exceed the 100 degree level my Wednesday in most low elevation production areas. A storm system passing over the Central Basin may produce windy cond- itions & cooling late in the week, but precipitation is unlikely with this storm. Temperatures should run about 5 degrees above normal this week. Heat unit (HU) accumulation in April was highest in 11 years (since 1989) in central & southeast production areas. April HU accumulation along the Colorado River was the highest in 7 years (since 1993). Spring emergence of PBW should be about 24% complete at this time. Heat Units (HU) are running about 9 days ahead of normal. HU last week = 126. Heat Unit accumulation since Jan 1 = 1018; Last year = 878; 30 year normal = 872. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .47" .47" .47" .47" .47" AGRONOMY UPDATE -------------------------------- Important steps in early cotton plant development that can be easily monitored in the field include the development of new nodes. In a relatively warm year, such as this one, plant growth and node generation will proceed rapidly. In general, we find that approximately 100 heat units (HU) are required to produce every new node, provided water is not limiting. The variation in HUs required to produce a new node is slight, but it can be predicted fairly well. If a crop has 700 HUAP, we should expect to find about 9 nodes on the plants and signs of early pinhead squares (PHS) being formed, hopefully at nodes 5, 6, or 7; or about 40 days after planting. Cotton related information from the UA can be accessed at http://ag.arizona.edu/cotton (JCS 4/29/00) ELOY COTTON DEVELOPMENT ADVISORY MAY 7, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | | 3/15************** 705 +5 days | v | | | | | | | | 4/1 *********** 565 +6 days | v | | | | | | | | 4/15******* 358 +2 days | | | | | | | | | 5/1 ** 101 +1 day | | | | | | | | | | 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 6 v = Heat Units on APR 29; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Sweetpotato/Silverleaf whiteflies (Bemisia spp.) are the pest WF of interest to most practitioners; however there are other WF species which may also be present in area fields, especially during the early season. Do not overreact to these other species which are less able to damage or contaminate the crop. Bandedwing WFs have gray bodies with gray-striped, white wings; pupae have dense waxy, short fringe. Greenhouse WF adults look like Bemisia WFs. Their wings completely touch or overlap over their backs; pupae have long thin fringe. Bemisia pupae are "naked," without a waxy fringe. Wings of Bemisia adults do not completely touch over the back & are held more roof-like. Both BWF & GWF decline as it warms up & Bemisia become more prevalent (pce 5/8). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : APR 30 - MAY 6 This Week : MAY 7 - MAY 13 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 90 54 32 115 ---- Normal 93 56 34 126 Recorded 98 55 28 132 0.00 1998 93 54 30 122 High pressure will continue to dominate AZ weather this week. Expect mostly sunny skies & dry conditions with above normal temperatures through Friday. Temperatures should average about 3 degrees above normal for the week. Heat unit (HU) accumulation in April was highest in 11 years (since 1989) in central & southeast production areas. April HU accumulation along the Colorado River was the highest in 7 years (since 1993). This advisory is available on the Internet at: http://ag.arizona.edu/azmet Spring emergence of PBW should be about 37% complete at this time. Heat Units (HU) are running about 9 days ahead of normal. HU last week = 132. Heat Unit accumulation since Jan 1 = 1150; Last year = 977; 30 year normal = 987. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .51" .51" .51" .51" .51" AGRONOMY UPDATE -------------------------------- The spring planting season has provided excellent conditions overall for seed germination and establishment. In contrast to the past two seasons, we have experienced only very minor problems associated with stand establishment in general across the state this season. As weather conditions have continued to be very hot and dry we are experiencing very rapid plant development in most areas. For example, we look for the first pinhead squares (PHS) at about 700 HUAP. First PHS are also often targeted for about 30-40 days after planting (DAP). With crop development moving at a rapid pace this season, several important events such as first in-season fertilizations and irrigations may be needed earlier than expected. (JCS 5/6/00) ELOY COTTON DEVELOPMENT ADVISORY MAY 14, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | v | | | | | | | 3/15***************** 846 +5 days | v | | | | | | | | 4/1 ************** 706 +6 days | v | | | | | | | | 4/15********** 499 +3 days |v | | | | | | | | 5/1 ***** 242 +2 days | | | | | | | | | | 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 13 v = Heat Units on MAY 6; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- While few insects pose a significant threat to pre-squaring cotton, some can do economic damage & may require control. Beet armyworm (BAW) is a common lepidopteran pest of seedling cotton. Typically, these infestations disappear over time due to weather, predation, & other factors. They even serve as food for a healthy complex of natural enemies that may be useful season-long. However, when infestations become so severe as to remove large portions of the available foliage, the plant will likely be weakened, lose time & require water sooner, and worse, plants may die. The need for control should be evaluated carefully so as to anticipate these outbreaks. This requires close tracking of populations over repeated field visits (pce 5/15). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 7 - MAY 13 This Week : MAY 14 - MAY 20 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 93 56 34 126 ---- Normal 95 57 34 134 Recorded 94 60 35 142 0.00 1998 95 54 33 125 A strong storm system will move across the Central Basin early this week, bringing very windy weather on Monday & Tuesday. Little precipitation is expected with this storm. Temperatures will run well above normal on Monday, then decrease to near normal levels for the rest of the work week. Long range forecasts call for a return to above normal temperatures by the weekend. Warm, dry April weather has accelerated plant development & crop water use this year. Growers are encouraged to closely monitor soil moisture conditions. Data from AZMET indicates irrigation intervals may need to be decreased by several days. Spring emergence of PBW should be about 54% complete at this time. Heat Units (HU) are running about 10 days ahead of normal. HU last week = 142. Heat Unit accumulation since Jan 1 = 1291; Last year = 1099; 30 year normal = 1113. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .7" .51" .51" .51" .51" AGRONOMY UPDATE -------------------------------- With the excellent start most cotton fields in AZ have experienced this season, we have the base from which to develop a strong foundation for a crop. Timing the first post-plant irrigation can have a significant impact on sub- sequent crop development and 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.(JCS5/12/00) ELOY COTTON DEVELOPMENT ADVISORY MAY 21, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | v| | | | | | | 3/15******************* 970 +5 days | v | | | | | | | 4/1 ***************** 830 +6 days | v | | | | | | | | 4/15************ 623 +3 days | v | | | | | | | | 5/1 ******* 366 +1 day | | | | | | | | | 5/15** 88 0 days | | | | | | | | | | 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 20 v = Heat Units on MAY 13; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- While few insects pose a significant threat to pre-squaring cotton, some can do economic damage & may require control. Beet armyworm (BAW) is a common lepidopteran pest of seedling cotton. Typically, these infestations disappear over time due to weather, predation, & other factors. They even serve as food for a healthy complex of natural enemies that may be useful season-long. However, when infestations become so severe as to remove large portions of the available foliage, the plant will likely be weakened, lose time & require water sooner, and worse, plants may die. The need for control should be evaluated carefully so as to anticipate these outbreaks. This requires close tracking of populations over repeated field visits (pce 5/21). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 14 - MAY 20 This Week : MAY 21 - MAY 27 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 95 57 34 134 ---- Normal 94 58 37 133 Recorded 93 55 33 124 0.00 1998 97 59 36 143 Sunny & hot this week. Very hot daytime temperatures will cause average temp- eratures to run about 10 degrees above normal. Precipitation is unlikely in central & western AZ due to the presence of high pressure & low humidity. A series of atmospheric disturbances may trigger some widely scattered mountain thunderstorms in eastern AZ. However, precipitation in eastern production areas is unlikely. Growers should closely monitor soil moisture conditions. Warm temperatures have accelerated crop development, & crop water use is running ahead of normal. Normal irrigation intervals may need to be shortened to avoid water stress. Spring emergence of PBW should be about 68% complete at this time. Heat Units (HU) are running about 9 days ahead of normal. HU last week = 124. Heat Unit accumulation since Jan 1 = 1415; Last year = 1224; Normal = 1247. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): .83" .61" .46" .46" .46" AGRONOMY UPDATE -------------------------------- Taking full advantage of early season growing conditions is critical for realizing good yields and efficient production. June, and the crop production period extending up to the first of the monsoon season is often referred to as the "Prime Time" for AZ cotton. Cotton plants can do very well in terms of growth and fruit retention (FR) under hot and dry conditions provided that water stress is eliminated and the plants are protected from pests. Split applications of fertilizer N are also important to provide between the formation of early squares and peak bloom. High crop vigor (i.e. height:node ratio, HNR) indicates rapid fruiting branch and fruiting site formation. Management for high FR and crop vigor are very important right now. (JCS 5/20/00) ELOY COTTON DEVELOPMENT ADVISORY MAY 28, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | |v | | | | | | 3/15*********************** 1133 +6 days | | v| | | | | | | 4/1 ******************** 993 +6 days | v | | | | | | | | 4/15**************** 786 +4 days | v | | | | | | | | 5/1 *********** 529 +2 days |v | | | | | | | | 5/15***** 251 +1 day | | | | | | | | | | 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 27 v = Heat Units on MAY 20; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Mites are ever present in our agroecosystem. Their populations are usually held in check by various physical & biological factors. Early-season sprays for other pests (e.g., aphids in alfalfa; thrips or beet armyworm in cotton) can lead to conditions favoring spidermite outbreaks. After an unusually warm & dry winter followed by hot spring conditions, scouts should spend more time looking for & then tracking mite infestations. Infestations are notoriously localized & scouts should spend time examining all parts of the field including field edges. Economic levels are poorly understood; however, dense populations can lead to stippling, bronzing, & ultimately leaf desiccation. If these conditions appear imminent, strive to spot treat the area where possible (pce 5/30/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 21 - MAY 27 This Week : MAY 28 - JUN 3 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 94 58 37 133 ---- Normal 98 60 35 144 Recorded 102 64 40 162 0.00 1998 90 57 39 121 High pressure will continue to dominate AZ weather this week. Expect sunny, hot & dry weather with daytime temperatures running about 10 degrees above normal. Low humidity will support rapid radiational cooling at night which should keep night temperatures at tolerable levels. Little chance for precipitation. Growers should closely monitor soil moisture conditions. Warm weather continues to support rapid crop development. Crop water use is running ahead of normal. Normal irrigation intervals may need to be shortened to avoid water stress. Spring emergence of PBW should be about 82% complete at this time. Heat Units (HU) are running about 10 days ahead of normal. HU last week = 162. Heat Unit accumulation since Jan 1 = 1578; Last year = 1367; Normal = 1380. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.23" .98" .6" .53" .53" AGRONOMY UPDATE -------------------------------- Good progression towards an early crop and high yields includes early fruiting and good early fruit retention (FR). Fields should be monitored to identify the location of the first fruiting branch (FFB) and for the rate of early square/boll retention. Many fields had FFB occur at node 7 or less at about 700 HUAP, which is excellent. If these squares are retained, first blooms will occur near 1200 HUAP, which has begun to take place recently with the earliest planted fields in the state. It is also important to monitor for any increase in square abortion in many areas. It is important to evaluate FR levels in fields, identify causes if FR levels are dropping, and address the causes for correction if at all possible. (JCS 5/27/00) ELOY COTTON DEVELOPMENT ADVISORY JUN 4, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | v| | | | | | 3/15************************** 1310 +7 days | | | v | | | | | | 4/1 *********************** 1170 +8 days | | v | | | | | | | 4/15******************* 963 +5 days | v | | | | | | | | 5/1 ************** 706 +4 days | v | | | | | | | | 5/15********* 428 +3 days | | | | | | | | | | 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 3 v = Heat Units on MAY 27; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- In June while the plant rapidly fruits, scout fields carefully & develop a 'profile' for each. Plant inspection, sweeping, and pheromone traps are all important tools for tracking the crop, & insect population development. Examine the growth habit of the plants, & sample terminals, half-grown squares & young bolls as they appear. Sweeps should be conducted in 2-4 locations per field for a total of at least 100 sweeps. PBW traps should be deployed & examined regularly as a guide to PBW movement & male activity. Taken as a whole, these measures reveal the character or profile of each field, & should influence interpretation of threshold guidelines through an understanding of plant health & beneficial insect activity along with pest population levels (pce 6/5/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : MAY 28 - JUN 3 This Week : JUN 4 - JUN 10 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 98 60 35 144 ---- Normal 99 60 35 147 Recorded 105 68 45 178 0.00 1998 97 55 31 135 Mostly sunny & very hot through mid-week with a slight chance for mountain thunderstorms near SE production areas. A Pacific storm system will pass through the Great Basin Thursday, resulting in windy weather & a return to normal temperatures Thursday & Friday. Little precipitation is expected with this storm system. The present 90-day forecast (through August) indicates a high probability for above normal temperatures, especially in west central AZ & along the Colorado River. The precipitation forecast is less definitive, but indicates a tendency for above normal precipitation in central and SE AZ. Spring emergence of PBW should be about 91% complete at this time. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 178. Heat Unit accumulation since Jan 1 = 1755; Last year = 1488; Normal = 1524. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.57" 1.31" .93" .53" .53" AGRONOMY UPDATE -------------------------------- Thus far this season, cotton crop development is proceeding very well across the region. In some cases, early square retention is low. It is important to monitor fields and identify fruit retention (FR) and vigor conditions. For example, at first bloom (1200 HUAP) FR should be 75% or more (counting first two fruiting sites on each fruiting branch) and height to node ratios (HNR) should be 1.0. It is also not uncommon at this time to find fields with vigorous growth (HNR above UA baselines) where mepiquat chloride applications may be considered. HNR measurements can be useful in making these decisions, particularly in identifying trends in crop growth. UA cotton guidelines and recommendations can be found at http://ag.arizona.edu/cotton (JCS 6/3/00) ELOY COTTON DEVELOPMENT ADVISORY JUN 11, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | v | | | | | 3/15****************************** 1480 +8 days | | | v| | | | | | 4/1 *************************** 1340 +8 days | | |v | | | | | | 4/15*********************** 1133 +6 days | v | | | | | | | 5/1 ****************** 876 +5 days | v | | | | | | | | 5/15************ 598 +3 days | | | | | | | | | | 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 10 v = Heat Units on JUN 3; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT 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 / field taking at least 25 sweeps / 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 but not before 4 NYMPHS / 100 are present. Earlier action is usually not economical (pce 6/12/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 4 - JUN 10 This Week : JUN 11 - JUN 17 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 99 60 35 147 ---- Normal 101 64 35 160 Recorded 103 66 42 170 0.00 1998 104 70 43 184 Sunny & hot with above normal temperatures through mid-week. A Pacific storm system will pass north of AZ on Tuesday & bring some cooler temperatures by mid-week. Above normal temperatures should return by late in the week. No precipitation is expected this week. The present 90-day forecast (through August) indicates a high probability for above normal temperatures, especially in west central AZ & along the Colorado River. The precipitation forecast is less definitive, but indicates a tendency for above normal precipitation in central and SE AZ. Spring emergence of PBW should be about 96% complete at this time. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 170. Heat Unit accumulation since Jan 1 = 1925; Last year = 1623; Normal = 1671. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.82" 1.57" 1.21" .75" .52" AGRONOMY UPDATE -------------------------------- June is prime-time for Arizona cotton. We need to make good use of this time in the season in all areas. With the hot and dry conditions which have been prevelant, maintaining plant vigor is important. Water stress should be avoid- ed for all fields and adequate nutrition provided, particularly N. Fields should be monitored for fruit retention (FR) levels and for general vigor conditions. Vigor can be evaluated with height to node ratios (HNR). Agronomy bulletins and guidelines outlining procedures for estimating FR and HNRs and also for using the information in managing N and PGR (PIX) applications are available through UA Extension offices and on the UA cotton website - http://ag.arizona.edu/cotton (JCS 6/10/00) ELOY COTTON DEVELOPMENT ADVISORY JUN 18, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | v| | | | | 3/15********************************* 1653 +8 days | | | | v | | | | | 4/1 ****************************** 1513 +9 days | | | v| | | | | | 4/15************************** 1306 +6 days | | v | | | | | | 5/1 ********************* 1049 +5 days | v | | | | | | | | 5/15*************** 771 +4 days | | | | | | | | | | 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 17 v = Heat Units on JUN 10; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Monsoon-associated winds, dust & rain can drastically change pest levels & can even significantly reduce WF egg & nymph populations. Sampling ensures proper timing of strategic insecticides like the IGRs -- the Applaud Sect. 18 is renewed for this season. Stickiness has cost AZ millions of dollars (see IPM No. 13). Sample both WF adults & nymphs on the 5th main stem leaf below the terminal; spray IGRs when 40% leaves have 3 or more 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). After a rain (24 hrs), do NOT sample WF adults; these numbers are unreliable. Point your browser to http://ag.arizona.edu/cotton for more information (pce 6/19/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 11 - JUN 17 This Week : JUN 18 - JUN 24 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 101 64 35 160 ---- Normal 105 66 37 171 Recorded 106 66 42 173 0.00 1998 106 70 48 184 Tropical moisture will continue to leak into AZ, especially in the eastern half of the state. Expect mostly sunny & hot days with moderate humidity. T-storms are possible most days over eastern AZ, especially in production areas adjacent to mountains. The long range forecast calls for a return to hot, dry conditions by late in the week. Temperatures should average about 5 degrees above normal for the week. The new 30-day forecast for July continues to indicate a high probability for above normal temperatures in western AZ along the Colorado River. July rainfall is forecast to be above normal, especially in eastern AZ. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 173. Heat Unit accumulation since Jan 1 = 2098; Last year = 1807; Normal = 1831. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.2" 1.94" 1.56" 1.09" .57" AGRONOMY UPDATE -------------------------------- In most cases cotton plant development is proceeding at a rapid pace with the hot and dry conditions we have experienced recently. One critical factor to consider at this, and all times of the season, is maintaining good soil-water conditions for the developing crop. The cotton plant can sustain hot and dry weather and continue to set and hold fruit with sufficient soil-water. Check soil-water content for irrigations at about 40 to 50 % soil-water depletion levels and try to avoid getting behind. For optimal efficiency of fertilizer N use by the crop, applications of fertilizer N (50-75 lbs. N/acre) should also be made in split applications before peak bloom (2000 HUAP) depending on crop condition. AZ cotton information @ http://ag.arizona.edu/cotton (JCS 6/17/00) ELOY COTTON DEVELOPMENT ADVISORY JUN 25, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v | | | | 3/15************************************* 1830 +8 days | | | | v| | | | | 4/1 ********************************** 1690 +8 days | | | | v | | | | | 4/15****************************** 1483 +6 days | | | v | | | | | | 5/1 ************************* 1226 +5 days | |v | | | | | | | 5/15******************* 948 +4 days | | | | | | | | | | 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 24 v = Heat Units on JUN 17; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Recent research suggests that chemical control of Lygus is best timed (for yields & economics) when there are at least 15 total Lygus with 4 nymphs per 100 sweeps present. Control of adults with current materials is weak at best. Fortunately, excellent yield protection can be accomplished through control of the nymphs. Use the best materials alone & at appropriate rates. Higher rates provide better residual control of nymphs. In this research, sprays made at levels lower than this (15:4) resulted in higher costs & lower yields. The 15:4 threshold serves as a guideline; other factors may impact your specific timing (e.g., irrigations, storms, pest complex, beneficials). http://ag.arizona.edu/pubs/crops/az1170/contents.html for info (pce 6/26/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 18 - JUN 24 This Week : JUN 25 - JUL 1 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 105 66 37 171 ---- Normal 107 70 42 183 Recorded 97 70 65 177 0.87 1998 106 75 59 198 Mostly sunny & hot this week with moderate humidity. The relatively dry air that entered AZ over the weekend will be replaced by more humid air by mid- week. Thunderstorms will be more likely during the latter half of the week, especially in southeast and central production areas. Temperatures should run about 5 degrees above normal this week. Cool temperatures have minimized potential heat stress resulting from monsoon humidity. The Yuma area did encounter some level 1 heat stress last week which is producing some light fruit shed in some areas. The current forecast of moderate humidity & hot temperatures may generate more widespread heat stress. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 177. Heat Unit accumulation since Jan 1 = 2275; Last year = 1991; Normal = 2002. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.55" 1.39" 1.15" .86" .55" AGRONOMY UPDATE -------------------------------- Crop condition and yield potential is very favorable for many fields as we end the month of June. It is likely that fruit retention (FR) levels may decline somewhat as plants balance the fruit load they can maintain and support. Also, with the recent changes in the weather patterns toward monsoon type conditions it is important to monitor fields and watch for changes in vigor (HNR) and FR. Noting changes in HNRs that are increasing above established baselines is im- portant for best timing of mepiquat chloride (PIXtm) applications and possibly adjusting fertilizer N applications. Information concerning mepiquat chloride and N management can be found on the web at the Arizona Cotton Information Site (ACIS) http:/ag.arizona.edu/cotton (JCS 6/24/00) ELOY COTTON DEVELOPMENT ADVISORY JUL 2, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v | | | | 3/15**************************************** 2022 +8 days | | | | | v | | | | 4/1 ************************************** 1882 +8 days | | | | v| | | | | 4/15********************************** 1675 +6 days | | | |v | | | | | 5/1 **************************** 1418 +5 days | | |v | | | | | | 5/15*********************** 1140 +4 days | | | | | | | | | | 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 1 v = Heat Units on JUN 24; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Pest management is mainly focused on the big 3 pests: PBW, WFs, & Lygus. Others tend to be secondary or of minor importance. Occasionally, conditions are right for outbreaks of other pests with which we might have generally less experience. Cotton fleahopper is a plant bug, much smaller & much less damaging than Lygus. These are more slender & lighter green, be-speckled bugs which appear to spend their time mainly in the terminals. The smallest nymphs are unlikely to cause square loss directly; however, larger nymphs & possibly adults may be able to feed & damage the smallest squares. No treatment thresholds are developed for AZ, but levels > 50 / 100 sweeps with documented square loss in the terminals should be cause for concern (pce 7/03/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUN 25 - JUL 1 This Week : JUL 2 - JUL 8 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 107 70 42 183 ---- Normal 104 72 53 188 Recorded 102 74 61 190 0.28 1999 102 75 65 193 A break in the monsoon! Drier air will reside over much of AZ through Friday. Expect mostly sunny skies with near normal daytime temperatures. Nights will cool relative to last week due to lower humidity. Little chance for rain except near the mountains in southeast AZ. Heat stress conditions were more prevalent last week. AZMET data indicates Level 1 heat stress conditions developed in central & western AZ last week. Light to moderate fruit shed is common during periods of Level 1 stress. Fortunately, the more damaging Level 2 heat stress was limited due to relatively cool temperatures. Level 2 stress often produces heavy & prolonged fruit shed. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 190. Heat Unit accumulation since Jan 1 = 2467; Last year = 2189; Normal = 2185. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.29" 2.08" 1.78" 1.4" .99" AGRONOMY UPDATE -------------------------------- It is important to monitor fields for fruit retention (FR), vigor (such as with a height:node ratio, HNR), and stage of growth. Fields in early bloom should have 8-10 nodes above the top (first position) white flower (NAWF). At peak bloom NAWF should be about 7. As plants progress toward cut-out the NAWF count will drop to 5 or less. It is very important to watch for changes in FR and HNR conditions in the field and try to detect any shifts in fruiting or vigor. For managing mepiquat chloride (PIXtm) applications, the HNR values are the most important to monitor. The best conditions to have a positive response (yield and growth) exist when HNRs are increasing above the UA baselines. See UA (PIXtm) recommendations at http://ag.arizona.edu/cotton JCS 7/1/00 ELOY COTTON DEVELOPMENT ADVISORY JUL 9, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | v| | | | 3/15******************************************** 2199 +7 days | | | | | v | | | | 4/1 ***************************************** 2059 +8 days | | | | | v | | | | 4/15************************************* 1852 +6 days | | | | v | | | | | 5/1 ******************************** 1595 +5 days | | | v| | | | | | 5/15************************** 1317 +3 days | | | | | | | | | | 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 8 v = Heat Units on JUL 1; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Insect Growth Regulators (IGRs) are more than just powerful WF insecticides. Their selectivity against WFs serves to conserve the natural enemies that are already present & active against WFs & other pests. This quality extends the effective interval of these compounds, as long as the use of other broad spectrum materials is minimized. Recent research has shown that this extended natural control of WFs can double the effective control period or "bio- residual" of the IGRs. So, use either IGR (Applaud, Knack) once there are at least 40% leaves infested with >=3 adults + 40% quarter-sized disks infested with large nymphs. Avoid mixing with broad spectrum materials where possible & wait long enough to realize the full benefit of these compounds (pce 7/10). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 2 - JUL 8 This Week : JUL 9 - JUL 15 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 104 72 53 188 ---- Normal 103 72 56 188 Recorded 102 69 55 177 0.05 1999 99 73 70 187 Mostly sunny with moderate humidity and near normal temperatures through mid- week. Widely scattered thunderstorms are possible near high elevation areas. More intense monsoon circulation is expected to set up by mid-week and bring more humidity and a greater chance for thunderstorms late in the week. Expect temperatures to average near normal for this week. Heat stress was not a major problem last week thanks to an unusually cool and dry weather pattern. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 177. Heat Unit accumulation since Jan 1 = 2644; Last year = 2382; Normal = 2373. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.49" 2.49" 2.18" 1.78" 1.34" AGRONOMY UPDATE -------------------------------- Maintaining a good balance between reproductive (squares, blooms, and bolls) and vegetative growth is always a primary objective in managing a cotton crop. The fruit retention (FR) and height to node ratio (HNR) baselines that have been developed by the University of Arizona provide an easy reference for use in evaluating a cotton field at any stage of development. If applications of mepiquat chloride (MC) are being considered it is most important to monitor crop vigor in terms of HNR measurements. If the HNR is found to be increasing or is above the UA HNR baseline, MC applications can possibly benefit plant growth control and yield. It is important to avoid MC applications to fields that have HNR values below the UA baselines. (JCS 7/8/00) ELOY COTTON DEVELOPMENT ADVISORY JUL 16, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v | | | 3/15************************************************ 2381 +7 days | | | | | v | | | 4/1 ********************************************* 2241 +7 days | | | | | v | | | | 4/15***************************************** 2034 +5 days | | | | |v | | | | 5/1 ************************************ 1777 +4 days | | | | v | | | | | 5/15****************************** 1499 +3 days | | | | | | | | | | 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 15 v = Heat Units on JUL 8; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Insect Growth Regulators (IGRs) are more than just powerful WF insecticides. Their selectivity against WFs serves to conserve the natural enemies that are already present & active against WFs & other pests. This quality extends the effective interval of these compounds, as long as the use of other broad spectrum materials is minimized. Recent research has shown that this extended natural control of WFs can double the effective control period or "bio- residual" of the IGRs. So, use either IGR (Applaud, Knack) once there are at least 40% leaves infested with =>3 adults + 40% quarter-sized disks infested with large nymphs. Avoid mixing with broad spectrum materials where possible & wait long enough to realize the full benefit of these compounds (pce 7/10). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 9 - JUL 15 This Week : JUL 16 - JUL 22 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 103 72 56 188 ---- Normal 102 72 57 187 Recorded 104 70 54 182 0.00 1999 99 73 66 188 The monsoon will continue to stay away from AZ for much of the week. Expect sunny & hot weather with below normal humidity this week. Long range fore- casts indicate monsoon flow may return by late in the week, bringing higher humidity and a chance for showers. Moderate temperatures & low humidity kept heat stress to a minimum last week. A brief surge of humidity combined with high temperatures to generate a 1-2 days of Level 1 stress late in the week in Maricopa Co. & western AZ. Location specific information on heat stress is on the web at http://ag.arizona.edu/azmet. Click on Cotton Advisories, scroll down the page, & then click your location. Heat Units (HU) are running about 10 days ahead of normal. HU last week = 182. Heat Unit accumulation since Jan 1 = 2826; Last year = 2569; Normal = 2561. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.26" 2.26" 2.23" 1.87" 1.47" AGRONOMY UPDATE -------------------------------- Many fields are at the peak bloom stage of development. At this stage in the season plants reach a maximum in terms of water and nutrient uptake and often growth rates. Applications of fertilizer N should be completed as close to peak bloom as possible. Later applications of fertilizer N are usually less efficient in terms of crop uptake and utilization and can complicate crop management in the later stages of the season. Late applications of N can lead to a high N fertility status for the crop that can cause delays in crop matur- ity, more vigorous vegetative growth (particularly if a drop in fruit reten- tion is experienced), and difficult crop defoliation. Peak bloom should occur near 2000 HUAP for most cases and with NAWF counts approximately 7. (JCS 7/15/00) ELOY COTTON DEVELOPMENT ADVISORY JUL 23, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | v | | | 3/15*************************************************** 2571 +7 days | | | | | | v | | | 4/1 ************************************************* 2431 +8 days | | | | | v | | | 4/15******************************************** 2224 +5 days | | | | | v | | | | 5/1 *************************************** 1967 +5 days | | | | v| | | | | 5/15********************************** 1689 +3 days | | | | | | | | | | 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 22 v = Heat Units on JUL 15; 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 7/24). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 16 - JUL 22 This Week : JUL 23 - JUL 29 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 102 72 57 187 ---- Normal 104 72 56 188 Recorded 108 72 54 191 0.00 1999 97 72 71 183 High pressure will continue to limit monsoon activity for much of the week. Expect mostly sunny & hot weather with moderate humidity. Precipitation is most likely in/adjacent to mountains & in southeast AZ. Temperatures should average about 3 degrees above normal. Hot temps & higher humidity produced heat stress across much of central & west- ern AZ late last week. Stress conditions approached/exceeded Level 2 stress at several western & central AZ locations, and fruit shed is likely as a result. More heat stress information is on the web at http://ag.arizona.edu/azmet. Click on Cotton Advisories, scroll down the page, & then click your location. Heat Units (HU) are running about 10 days ahead of normal. HU last week = 191. Heat Unit accumulation since Jan 1 = 3016; Last year = 2757; Normal = 2748. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.65" 2.65" 2.65" 2.51" 2.04" AGRONOMY UPDATE -------------------------------- Fruit retention and crop condition is generally good but highly variable throughout this area. As fields progress through peak bloom and into the later stages of the primary fruiting cycle, it is important to continue monitoring both the fruit retention (FR) and height to node ratios (HNR) in relation to the established guidelines for AZ. If excessive vegetative growth is taking place (high HNR relative to baselines) an application of mepiquat chloride (MC) may be considered. Applications of MC with proper rates can often reduce vegetative growth. For best results in terms of improving yield with MC appli- cations, it is important to do so only in cases where the HNRs are above the AZ baselines. Refer to UA bulletins http://ag.arizona.edu/cotton (JCS 7/22/00) ELOY COTTON DEVELOPMENT ADVISORY AUG 6, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15*********************************************************** 2968 +7 days | | | | | | v | | 4/1 ********************************************************* 2828 +8 days | | | | | | v | | | 4/15**************************************************** 2621 +6 days | | | | | | v | | | 5/1 *********************************************** 2364 +5 days | | | | | v | | | | 5/15****************************************** 2086 +4 days | | | | | | | | | | 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 5 v = Heat Units on JUL 29; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- With the onset of summer rains and increased humidity, Southwestern cotton rust and Alternaria leaf spot could become problems. Many Pima varieties are very susceptible to Alternaria leaf spot, and all cotton varieties in Arizona are susceptible to rust. Heavy infections have been reported to cause yield reductions, but light infections are probably not a problem. Both diseases require several hours of free moisture for disease development. Mancozeb fungicide applications can prevent both diseases, but it is not curative, and must be applied before spores germinate on leaves. Applications should be made in suspect fields with a history of disease and in anticipation of rainfall (mo 8/07). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : JUL 30 - AUG 5 This Week : AUG 6 - AUG 12 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 105 75 57 196 ---- Normal 104 73 62 191 Recorded 107 74 61 194 0.39 1999 100 70 61 180 Mostly sunny & very hot with moderate humidity this week. Scattered monsoon thunderstorms are possible each day, especially near high elevation areas. Temperatures are expected to run about 5 degrees above normal for the week. Hot temperatures & normal early August humidity generated another stressful week for cotton growing in central & western AZ. Location specific information on heat stress is available on the web at http://ag.arizona.edu/azmet. Click on button labeled Cotton Advisories & scroll down to section containing heat stress reports. Then click on location of interest. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 194. Heat Unit accumulation since Jan 1 = 3413; Last year = 3131; Normal = 3133. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 2.4" 2.4" 2.4" 2.4" 2.4" AGRONOMY UPDATE -------------------------------- In the past few weeks fruit retention (FR) has declined to some extent in some fields, particularly from small boll shed, which is common with this type of weather and the fruit load many fields have. However, many fields are reaching sufficient maturity so that damage to yield potential should be slight. The number of nodes above the top (first pos.) white flower (NAWF) can be used as an estimate of crop maturity. When the NAWF counts drop to 5 or less the crop is moving into cut-out. Plants should have about 25-30 total nodes at this stage of the season, with about 20 fruiting branches. Yield estimates can be taken by using 15-20 bolls/ft. of row equalling 1 bale of lint/acre. This measure depends on boll size and can be somewhat variable. (JCS 8/5/00) ELOY COTTON DEVELOPMENT ADVISORY AUG 13, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15*************************************************************** 3159 +8 days | | | | | | | v | | 4/1 ************************************************************ 3019 +8 days | | | | | | v| | | 4/15******************************************************** 2812 +6 days | | | | | | v | | | 5/1 *************************************************** 2555 +5 days | | | | | |v | | | 5/15********************************************** 2277 +4 days | | | | | | | | | | 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 12 v = Heat Units on AUG 5; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT 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 => 3 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 8/14). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 6 - AUG 12 This Week : AUG 13 - AUG 19 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 104 73 62 191 ---- Normal 102 73 63 191 Recorded 101 74 66 191 0.44 1999 104 72 64 187 Mostly sunny & hot with moderate humidity & scattered thunderstorms through mid-week. A developing tropical depression in the Gulf may impact weather late in the week by producing higher humidity, increased cloudiness, cooler temperatures and more widespread precipitation. Temperatures for the week should average about 3 degrees above normal. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 191. Heat Unit accumulation since Jan 1 = 3604; Last year = 3311; Normal = 3324. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.94" 2.08" 2.08" 2.08" 2.08" AGRONOMY UPDATE -------------------------------- To consider the proper timing of the last irrigation, it is important to iden- tify the last set of flowers intended for harvest. Boll development from a flower to a full-sized, hard green boll requires approximately 600 HU. The 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. Bolls are mature if seed coats are tan or brown and the seed embryos show tiny folded leaves. Final irrigations should support the development of that last set of flowers. (JCS 8/12/00) ELOY COTTON DEVELOPMENT ADVISORY AUG 13, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15*************************************************************** 3159 +8 days | | | | | | | v | | 4/1 ************************************************************ 3019 +8 days | | | | | | v| | | 4/15******************************************************** 2812 +6 days | | | | | | v | | | 5/1 *************************************************** 2555 +5 days | | | | | |v | | | 5/15********************************************** 2277 +4 days | | | | | | | | | | 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 12 v = Heat Units on AUG 5; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT 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 => 3 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 8/14). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 6 - AUG 12 This Week : AUG 13 - AUG 19 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 104 73 62 191 ---- Normal 102 73 63 191 Recorded 101 74 66 191 0.44 1999 104 72 64 187 Mostly sunny & hot with moderate humidity & scattered thunderstorms through mid-week. A developing tropical depression in the Gulf may impact weather late in the week by producing higher humidity, increased cloudiness, cooler temperatures and more widespread precipitation. Temperatures for the week should average about 3 degrees above normal. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 191. Heat Unit accumulation since Jan 1 = 3604; Last year = 3311; Normal = 3324. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.94" 2.08" 2.08" 2.08" 2.08" AGRONOMY UPDATE -------------------------------- To consider the proper timing of the last irrigation, it is important to iden- tify the last set of flowers intended for harvest. Boll development from a flower to a full-sized, hard green boll requires approximately 600 HU. The 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. Bolls are mature if seed coats are tan or brown and the seed embryos show tiny folded leaves. Final irrigations should support the development of that last set of flowers. (JCS 8/12/00) ELOY COTTON DEVELOPMENT ADVISORY AUG 20, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | v | | 3/15******************************************************************* 3349 +8 days | | | | | | | v | | 4/1 **************************************************************** 3209 +8 days | | | | | | | v | | 4/15************************************************************ 3002 +6 days | | | | | | v | | | 5/1 ******************************************************* 2745 +5 days | | | | | | v | | | 5/15************************************************* 2467 +4 days | | | | | | | | | | 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 19 v = Heat Units on AUG 12; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- Aflatoxin, a serious carcinogen produced by the fungus Aspergillus flavus, contamination occurs in 2 phases: the 1st with insect damage prior to seed maturity; the 2nd involves direct penetration by A. flavus after seed maturity. In AZ, aflatoxin contamination of cottonseed increases as elevation decreases. More importantly, aflatoxin content in cotton has been correlated with date of ginning for both transgenic Bt & non-Bt cotton (contamination increases in later ginned cotton). In areas where aflatoxin is historically a problem, harvest date is an important consideration for aflatoxin management. Early harvest & ginning may keep seed contamination levels below the 20 ppb or 300 ppb allowable for dairy feed & cattle feed, respectively (mo 8/21/00). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 13 - AUG 19 This Week : AUG 20 - AUG 26 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 102 73 63 191 ---- Normal 101 74 64 189 Recorded 104 73 63 191 0.11 1999 104 73 65 192 A typical monsoon forecast. Mostly sunny & hot with moderate humidity & scattered thunderstorms. Present forecasts indicate the best chance for rain will be on Wednesday & Thursday. Temperatures for the week should average near normal. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 191. Heat Unit accumulation since Jan 1 = 3794; Last year = 3498; Normal = 3514. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.74" 1.92" 2.13" 2.13" 2.13" AGRONOMY UPDATE -------------------------------- Crop progression into cut-out is easily identified when the number of nodes above the top (first position) white flower (NAWF) is 5 or less. The most re- cent first position bloom can also be used for this measure. True cut-out is when the NAWF=0, which marks the end of the first fruiting cycle. Regrowth and additional nodes associated with the second fruiting cycle will usually be generated even if one is not attempting to grow a top-crop. The cut-out zone on the mainstem can often be identified by a zone of short, compacted inter- nodes. At this time decisions need to be made relative to irrigation termina- tion. The last group of bolls intended for harvest will need 600 HU for full fiber development by the time they develop into hard green bolls.(JCS 8/19/00) ELOY COTTON DEVELOPMENT ADVISORY AUG 27, 2000 PLANTING +/- normal DATE+-------------------------------------------------------------------------+ | | | | | | | | | | | | | | | | | v 3537 | 3/15*********************************************************************** +8 days | | | | | | | v| | 4/1 ******************************************************************** 3397 +8 days | | | | | | | v | | 4/15**************************************************************** 3190 +6 days | | | | | | | v | | 5/1 *********************************************************** 2933 +5 days | | | | | | v | | | 5/15***************************************************** 2655 +4 days | | | | | | | | | | 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 26 v = Heat Units on AUG 19; S,M,F = Short, Medium, and Full Season Varieties PEST MANAGEMENT UPDATE -------------------------------- The fungus Aspergillus flavus, the producer of aflatoxin in cottonseed, has 2 strains. The S strain consistently produces large amounts of aflatoxin while the L strain is a low producer. Distribution of aflatoxin in cotton fields is the result of the relative mix of S & L strains in soils. Incidence of the S strain increases in warm periods & decreases in cool periods such as the El Nino weather patterns. This agrees with statewide surveys indicating that S strain incidence is high in soils at low elevations in southwest Arizona & very low at higher elevations in southeast Arizona. Reduction of aflatoxin contamination by replacement of the S strain with non-toxic strains by soil inoculation is the subject of on-going studies by the USDA & ACRPC (mo 8/28). WEATHER UPDATE, STATISTICS & ESTIMATED COTTON WATER USE -------------------------------------------------------------- Last Week : AUG 20 - AUG 26 This Week : AUG 27 - SEP 2 HIGH LOW DEWPT HUs RAIN HIGH LOW DEWPT HUs Normal 101 74 64 189 ---- Normal 100 72 64 184 Recorded 102 72 62 187 0.02 1999 97 70 70 174 Tropical moisture will reside over much of AZ through mid-week. Expect partly cloudy & humid conditions with below normal temperatures & a good chance for showers & thunderstorms through Wednesday or Thursday. Drier conditions are forecast to develop by Friday with a return to more seasonable temperatures. Heat Units (HU) are running about 11 days ahead of normal. HU last week = 187. Heat Unit accumulation since Jan 1 = 3982; Last year = 3690; Normal = 3703. Planting date : 3/15 4/1 4/15 5/1 5/15 Water Use (last week): 1.43" 1.61" 1.88" 2.06" 2.06" AGRONOMY UPDATE -------------------------------- As we approach the later stages of the 2000 cotton season, the general assess- ment statewide for the Arizona crop is very positive. We have been very fortu- nate this season in terms of favorable weather patterns from the early plant- ing season to the end of the fruiting cycle for most areas. The warm and open weather of the planting season provided an opportunity for establishing an excellent foundation to the crop. Crop growth and development patterns in May through August were very conducive to early fruit formation and retention. Growers in most areas were able to capitalize on these opportunities and establish a rather strong and uniform fruit load. We have the potential to realize good yields and fiber quality this season. JCS (8/26/00) THIS IS THE FINAL COTTON ADVISORY FOR 2000. HAVE A SAFE AND PROFITABLE HARVEST SEASON !