Texas Agricultural Extension Service

Volume XXVII No. 19 July 6, 2001 GENERAL SITUATION: We got rain. The amounts varied from ½ to over 4 inches on Monday and Tuesday of this week. Cameron and Hidalgo counties seemed to have had the most rain. But, everybody shared in this week's moisture. Grain sorghum and corn harvest continued to be delayed and cotton boll opening and defoliation were also delayed. In most cases, rain was not needed to finish the cotton crop, but will leach salts from the soils for the next crop. Defoliation Cotton bolls were opening rapidly this week. Commercial cotton field defoliation will commence for the earliest planted and many dryland cotton fields as soon as the fields dry enough. Regrowth on cotton which "cutout" over 4 weeks ago will make defoliation more challenging this season. Regrowth cotton, whenever it occurs, is a tougher plant to defoliate than a plant that has few or no new leaves. The rains this week will only make for more regrowth. Texas A&M Defoliation Trial The Texas A&M Research and Extension Center's defoliation test was applied last Thursday, June 28. There are at least 35 different combinations and single harvest aide materials applied in the test. The defoliation trial at the Texas A&M Center's Hiler farm is located at the same location as the Field Day event which was conducted Friday, July 6. The location is provided on the attached road map. Additional Defoliation Trials Two other cotton defoliation trials were started this week. Rio Farms has a trial northwest of Hargill on Lot 10 & 11 of the MTL&I subdivision (call Rio Farms at 262-1387 for further details of location) and another conducted on the Galle Farms field, ½ mile west of the Villegas Store (, southwest of the Lyford Coop(The Villegas Store is at the intersection of business 77 and FM 498, south of Lyford). Both of these trials should be ready for viewing next week. Dale Merden, with Rio Farms, said that he would be glad to take people who wish to see their defoliation trial. A field day for the Galle Farm Defoliation trial will be held at 10:00am, Friday, July 13 at the defoliation site. We recommend that producers across the Valley try to visit at least one of the three trials mentioned here. Given the crop conditions that rains have brought to the end of the season, the same old tried and true defoliant/defoliant combinations and rates may not work as usual. These trials should provide some insight into what may work better for our area this year. Cotton Harvest Nearing Obviously, with all of the discussion about cotton defoliation, cotton harvesting will commence in about two weeks. The only obstacle to harvesting will be rain.

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PEST CAST continued

Some fields had reached 40 to 50 percent open bolls by the end of this week and should be ready for defoliation next week. The early planted irrigated fields and many dryland fields appeared headed for the earliest harvest dates. This year, the amount of early harvest could be significantly more than usual due to the excessively dry weather in the dryland areas of the LRGV.

Yield potential in irrigated fields looked excellent for the most part. Boll counts in excess of 30 per foot of row were noted a few fields. Thirty bolls per foot could represent a potential of 2+ bales per acre.

Boll Weevils Increasing
in the Field & Traps

Boll weevils continued to increase, especially in fields with plenty of squares and blooms left. Most dryland and many irrigated fields appeared to have reached the end of weevil concern due to the fact that there were few fruit forms other than large bolls on which they could feed and lay eggs. Weevils were also leaving mature fields and moving to younger ones with fruit. The emigration of weevils with the ones emerging from squares and small bolls inside the younger fields was causing the major increases noted in some fields this week. Punctured squares ranged from 0 to 60 per 100 plants. Adult weevils were much easier to find this week since many were found in blooms. Later maturing fields need constant attention for weevils if the crop is to finish with a good yield.

Weevils caught in traps also showed significant increases in some traps this week.

A few of the hot spots recorded earlier this season have returned as hot spots in the latest trappings (See trap graphs with this Pest Cast).

All Worms in Light Infestations

Bollworm, beet armyworm, loopers and even a few saltmarsh caterpillars were observed in very light numbers in scattered fields this week. No reports of crop-damaging infestations of any of the aforementioned pests were received by our offices this week.

Whiteflies Still Present

Silverleaf whiteflies (SLWF) still were being found and reported from cotton fields, especially in the mid and lower Valley areas. The recent rains slowed SLWF, but following the rain, adult and immature whiteflies still were easy to detect in some fields. Later maturing fields need very careful monitoring for SLWF since they could pose a problem with sooty mold.

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