Pest Cast

Texas Agricultural
Extension Service

Volume XXVII No. 20

July 13, 2001

GENERAL SITUATION: Another hot and dry week. Cotton, grain sorghum and corn harvests need the dry weather. Some harvesting of all three crops was underway this week. Boll weevils continued to increase in fields with squares and green bolls.

Boll Weevil Trap Numbers Up Again

Boll weevil traps showed increasing boll weevil captures this week (See trap records in this issue). Some weevil movement to traps appeared to have been delayed slightly due to the extra large amount of new squares and small bolls being formed in nearly all cotton fields. The recent rains renewed growth in otherwise cutout cotton fields and new fruit formed which is supplying boll weevils with both food and reproductive sites. Even though most of the crop appears to be "safe" from yield damage by boll weevils, you should consider a variety of tactics that will help next year's efforts against boll weevils.

Consider Stalk Destruction Now

Destroying the food and reproductive sites either through crop destruction if the crop is insured out, defoliating (and adding an insecticide with the defoliant) and harvesting as quickly as possible following defoliation and then a quick and thorough crop destruction should reduce weevil numbers posing a threat to next year's crop.

Add Insecticide to Herbicides

If shredding stalks before either plowing or using a herbicide to kill the stalks, use an insecticide for weevils immediately behind the shredder. Boll weevils will be more exposed following stalk shredding than at any other time of the season and control of large numbers of weevils should be much more effective.

Adding an insecticide with the herbicide in conservation tillage fields will help reduce boll weevils that could be going into diapause and seeking overwintering sites. If more than one application of herbicide is used to kill the cotton stalks, then add insecticide each time to insure fewer weevils survive for next year.

Silverleaf Whiteflies

Silverleaf whiteflies continued to be of concern in some fields this week. Numbers appeared to be lower in some fields than they had been a week ago, but still were easily observed flying away from plants which were moved even slightly.

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The Texas A&M University System, U.S. Department of Agriculture, and the County Commissioners Courts of Texas Cooperating.

PEST CAST continued

Bollworm/Budworm Numbers
Continue Low

Bollworm/tobacco budworms were in low numbers and did not appear to be posing a threat to any fields this week. No counts were reported to our offices, but all immature fields should be monitored carefully for any sudden change in bollworm or budworm numbers and damage.

Cottonleaf Perforators Appearing Now

Cottonleaf perforators were noted in increasing numbers in a few fields this week. The hot and dry conditions favor perforator increases since the weather conditions tend to toughen cotton plants and that is the kind of plants perforators prefer. Most years, perforators pose no serious threat to cotton, but when heavy, they can cause deterioration of the leaf canopy and reduce defoliant efficacy. No thresholds exist for perforators, but if leaf damage is severe control may be necessary.

Cotton Heat Unit Accumulation Table
Planting Dates	Accum. H.U.	Planting Dates	Accum. H.U.
2/15	2544	3/15	2287
3/01	2399	4/01	2161

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.

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