Web Site: http://entowww.tamu.edu
Vol. 30, No. 4

COTTON

Cotton ranges from early square stage to small bolls. Early planted cotton has been blooming about a week now. One field was observed on July 4 with an average of two blooms per plant and thumbnail size bolls. Most fields should reach the bloom stage in 6 to 10 days.

Percent square sets have continued to increase in most fields over the last 10 days. Fields have ranged from 82 to 97 percent square set; which is considered to be excellent at this point in the season. Cotton fleahoppers and Lygus bugs continue to be found over the area, but populations remain light.

Lady beetles continue to hold our cotton aphid populations in check. Overall aphid infestations remain very light and colonies only found on an occasional leaf.

Cotton bollworm infestations have been found in a few cotton fields, with infestations ranging up to 2,500 per acre. Trap collections of cotton bollworm /corn earworm have been variable depending on trap location. The highest trap collected 461 moths per week ending on July 4, while the lowest trap collection was 9 moths for the same period. Both of these traps are located in the Edmonson/Kress area. Traps in the Cotton Center/Hale Center area averaged 120 moths/week for a period ending on July 2.

Beet armyworms have been reported in several area cotton fields, but numbers remain light. Traps in the Edmonson/Kress area averaged 145 BAW moths/week for the periods ending on July 4; while traps in the Cotton Center/Hale Center area averaged 285 moths/week for the period ending July 2.

Treatments for boll weevils continued this week by the Texas Boll Weevil Eradication Foundation. So far acreage treated on a weekly basis has remained very low. The following table shows acreage treated in our zone by week.

Boll weevil trapping is less effective after cotton reaches the 1/3 grown square stage. If growers, private consultants or aerial applicators find punctured squares in a cotton field please notify the TBWEF with the location of your field.

SORGHUM

Sorghum is in the late whorl stage with corn leaf aphid populations moderate to heavy. In most cases commercial hybrids are very tolerant of these pest.

In seed production some female lines are very sensitive to feeding by this aphid.
Before treating seed lines check with your seedsman about sensitivity to damage by corn leaf aphid.

A few greenbugs have been found in area fields, but populations remain light. Also fall armyworms have been observed damaging foliage in whorl stage sorghum, but infestations are generally lighter than the past two years.

CORN

Many fields are now tasseling and silking. The earliest tasseling corn in the area was observed on June 21 east of Plainview.

Collections of southwestern corn borer in pheromone traps remain very low at this time. With the high adoption rate of Bt corn hybrids it has been difficult to locate a population with which to run our SWCB prediction model. If consultants or growers know of a site with a significant infestation, please contact our office. A sample of about 35 to 50 southwestern corn borer larvae from a field are needed to run a model prediction.

Banks grass mites are on the increase in some area fields. Infestations have been confined to the lowest leaves on the plant, with some of the larger colonies 4 inches long next to the midrib on the underside of the leaf.

Fall armyworms have also been found in corn. Larvae have growth stage ranged from 3rd to 5th instar larvae. Generally less than 10% of the plants have been infested.

Corn earworm infestations have also been in the 5 to 10% range which is the norm in recent years. As we enter the silking stage corn becomes very attractive to this moth and should help alleviate egg lays which should occur in cotton.

SUNFLOWER

As sunflowers enter the bloom stage it is important to scout for sunflower moth movement into the field. We generally target the first application at 20% bloom. The new sunflower varieties are very uniform in their bloom period and can go from 5% bloom to 20% bloom in 1 day. The following table shows the progression of bloom in a confectionary sunflower field recorded in the Edmonson area in 2000.

From this one can see the total bloom period occurred in about 12 days. Once you see the 1st yellow ray flowers visible scout your field daily for moths and % bloom. Once you find 3 to 5% bloom and sunflower moths are present in the field an insecticide application should be targeted for the following morning when flowering will reach 19 to 21% bloom.

Greg Cronholm, Extension Agent - IPM,
122 East 6th, P.O. Box 680
Plainview, TX. 79073-0680
806-291-5273
Ento. Dept. Website: http://entowww.tamu.edu
Dist. 2 Website: http://lubbock.tamu.edu
E-Mail: g-cronholm@tamu.edu

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