Volume XXVII No. 16 July 12, 2002 Defoliation Field Day Cotton defoliation is an ever changing set of circumstances. Each year growers put on their usual or tried and true mixtures and get slightly different results each season. We have a defoliation field trial that was applied on July 10, that hope will give growers an idea of what products and combinations of products are working this year. We will have results at a Cotton Defoliation Field Day at the Texas Agricultural Experiment Station "Hiler" Annex farm near Mile 10 North about ½ mile east of FM 1015 north of Weslaco on July 18th. We will present the results and allow anyone interested to go through the plots to see the different treatments starting at 6:00 PM on the 18th. We will also have a sponsored meal for those attending the field day at the same location. GENERAL SITUATION: A mixed bag of weather in the LRGV the past two weeks. Some rain which ranged from 1/4 to over 5 accumulated inches. Most of the rain that fell on dryland fields did little good. Rains that fell on irrigated cotton areas helped to finish irrigations for most of the fields. Some fields will need additional moisture to finish a normal crop this season. Boll weevils have increased rapidly in the last week. Leaf Killing Phenomenon Hits Area Cotton Cotton leaves were observed to be rapidly dying in many area fields over the last two weeks. Many area fields had whole or partial areas of fields with defoliated plants. The problem is much more severe in older, mature fields and appears to be across most varieties. I have a 48 variety trial at the annex farm at the Texas Agricultural Experiment Station just north of Weslaco and every variety in it has the problem. The more mature varieties were the worst affected so far. The more open bolls in any particular variety, the more of the leaf kill that was observed. Stressed areas within plots generally have more damage than non stressed areas. But, as more bolls open within the less stressed areas, the more leaves begin to curl and die. Whatever the problem is, it does not appear to be the same as Bronze wilt which has been mentioned as a possibility. The leaves turn purple, then begin to turn brown, curl and fall off the plant. Some of the plants with the worst case situations went from normal looking cotton on Friday (July 5) looking good to complete loss of leaves by Monday (July 8). Similar leaf kill has been reported from the Corpus Christi, Wharton and Williamson county (central Texas) county areas as well. We hope to have some experts down to look at this situation early next week. We will keep everyone informed as we get more information.

Educational programs conducted by the Texas Agricultural Extension Service serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin.
The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.

PEST CAST continued

Cotton Defoliation and Harvest Underway

Some cotton was defoliated early last week and more was underway this week. Cotton harvesting will start shortly, if in fact, it has not already begun. Weather delays will be the only obstacles to overcome to move steadily forward with this year's cotton picking. Currently, dry weather is predicted for the next few days. More rain was predicted for Sunday through Tuesday (July 14-16). The way this season has gone, odds are in favor that this rain will fall as predicted since it is harvest time.

Weevils on a Rampage

Boll weevils were increasing fast, especially in less mature fields. Many weevils could be found in blooms...kind of like the old story about 5 to 6 weevils feeding in the bloom and one on the lookout for the airplane. Damage from weevils ranged from 5 to 80 punctured squares per 100 plants. The older, more mature fields were not seen as major targets of weevils this week since many open bolls and few squares or young bolls were left. Fields with large numbers of bolls which are less than 14 days old will likely need continued protection from weevils.

Season-Ending Weevil Mgt. Plans

The cotton season is clearly winding down in the LRGV. Growers should be considering end- of-the-year weevil management plans which should include adding an insecticide to the defoliants. If conservation tillage of cotton fields is in your farm's operational plan for this year, then add an insecticide to each application of herbicide made to cotton fields. The addition of insecticides to the end of the season will reduce adults which are moving from field to field and will aid in the reduction of weevils which could overwinter. Added to the other plans of complete stalk destruction and previous spring and summer weevil management strategies can be effective in reducing weevils in LRGV cotton. Talk to your neighbors and encourage them to complete the same practices. The more the better the results will be.

Aphids Need Watching

Aphids were increasing dramatically in some fields. Insecticidal control may be necessary in some cases to prevent large amounts of honey dew from being deposited on open lint and leading to quality reductions. Not all fields had aphids in high numbers and so each field should be checked separately to determine if aphids are a problem.

Other Late Season Pests Light

Bollworms and other worm pests like beet armyworms and cabbage loopers were in very low numbers this week. Younger fields should be monitored extra hard since that will be the targets of any late season pests.

THE INFORMATION GIVEN HEREIN IS FOR EDUCATIONAL PURPOSES ONLY. REFERENCES TO COMMERCIAL PRODUCTS OR TRADE NAMES ARE MADE WITH THE UNDERSTANDING THAT NO DISCRIMINATION IS INTENDED AND NO ENDORSEMENT BY THE COOPERATIVE EXTENSION SERVICE IS IMPLIED.

Posted at this web site by:
texagnet Internet Services.