Northwest Plains
Pest Management News
Volume 1 Issue 6
Bailey and Parmer Counties
July 19, 2002

Current Crop Conditions

The Cotman computer model is indicating a loss of vigor in most fields. The primary reasons for this loss of vigor is deficient irrigation and increased fruit load. Square set is very good, 79 to 95% in area program fields. Many fields do not have the irrigation capacity to continue this pace much longer without the help of a good rain. Irrigation needs to be intensified where possible, as the water reqirements are rising fast. The row water is particularly hard to manage, you have to start early and may still finish late. Corn continues to look very good for the most part. Some fields are finished pollinating while others have yet to tassel. The cob, shank, and husks have fully developed and the kernals are rapidly increasing in dry weight on the early planted corn. Corn earworm are present in most fields but pose no economic loss potential in field corn.

Daily Water Requirements

Crop
Inches Per Day
Cotton
.27
Corn
.35
Grain Sorghum
.27

 
Heat Units
Current
2001
Corn (April 1st planting)
2038
1967
Cotton (April 20th planting)
1020
988
Cotton (May 1st planting)
922
951
Cotton (May 15th planting)
927
893

Southwestern Corn Borer

Southwestern corn borers continue to increase in numbers. Heaviest infestations are east of Highway 214 but are moving west. Check for egg masses to determine the potential infestation and the correct timing of insecticide application. Insecticide should be applied when 20 to 25 percent of the plants are infested with eggs or newly hatched larvae.

Plant Bugs

Both fleahopper and Lygus bug numbers remain below treatment levels for the most part. Some fields did have some retention problems but these problems could often be traced to inclement weather or variety. Once cotton is blooming, the threat from fleahopper damage is all but over. In fact, this pest now can be counted as an ally as it will also feed on eggs and other pest stages. Unfortunately, Lygus will become more of a nuisance and a pest as cotton moves through July and into August. Later developing fields could be most vulnerable to yield losses from this pest.
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Bollworms

A heavy egg lay has started in some cotton fields in the Lubbock / Slaton area. Cotton needs to be scouted regularly for this pest. Moths are attracted to and lay eggs readily in cotton that is producing an abundance of new growth. Survival rate of larvae are higher in these fields as well. Moths usually lay single eggs on the tops of young, tender terminal leaves in the upper third of the plant. Eggs are pearly white to cream color and about half the size of a pinhead.

Caterpillars can grow up to about 1 5/8 inches in length and vary in body color from yellowish, greenish, reddish or brownish with more or less prominently colored longitudinal lines. The body is covered by regularly occurring body-colored to black bumps sporting stiff black hairs.The head capsules are tan to dark brown. Young worms usually feed for a day or two on tender leaves, leaf buds and small squares in the plant terminal before moving down the plant to attack larger squares and bolls. When small worms are in the upper third of the plant, they are most vulnerable to control by insecticides and beneficial insects and spiders. Count the number of eggs, worms and key predators encountered and estimate the number of eggs, worms, and key predators per acre.

Boll Weevil Eradication

No boll weevils were caught north of Hwy 145, 8379 traps inspected. No boll weevils were caught south of Hwy 145, 11965 traps inspected. Failed cotton must be kept non-hostable to avoid the TBWEF assessment.

Trapping
Beet Armyworm
North of Hwy 145 661 in 25 traps
South of Hwy 145 75 in 25 traps
Corn Earworm 721 in 6 traps

Treatment may be justified when counts average 5,000 or more small worms per acre. However, if two or more key predators are found for each small worm, control measures may not be needed or a microbial insecticide may be used.

Monti Vandiver
Extension Agent-Integrated Pest Management
Texas Cooperative Extension
401 3 rd Street
Farwell, Texas
806-481-3300
Educational programs conducted by Texas Cooperative Extension serve people of all ages regardless of socioeconomic level, race, color, sex, religion, handicap or national origin. The information given herein is for educational purposes only. References to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas Cooperative Extension is implied.
The Texas A&M University System, U.S. Department of Agriculture, and the Commissioners Courts of Texas Cooperating
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