Web Site: http://entowww.tamu.edu
Vol. 30, No. 9

COTTON

Many more cotton fields have entered the cut out stage over the past week with only 2 to 4 nodes above white bloom. The recent rainfall ranged from a few tenths to over one inch. Many area cotton fields had from 0.6 to 1" of rain which has helped growers to catch up temporarily with irrigation requirements. The cooler temperatures have also reduced stress on cotton. One disadvantage with cooler wet weather is that cotton bollworm survival increases. This past week bollworm egg lays have continued ranging from a few thousand per acre to over 100,000 eggs per acre. The highest bollworm egg lays have been observed where a significant amount of corn has been planted.

High egg counts have also been reported in cotton fields that have been recently treated for bollworms. The pyrethroid applications do not prevent additional egg lays, but they may suppress moth activity for a day or two.

Larval counts have increased in some fields and predators are having a difficult time holding bollworm populations in check as some fields have now had eight days of continuos egg lay. Larval counts have ranged form 0 to 20,000 per acre.

Collections of cotton bollworm moths in pheromone traps has been lower than expected based on the significant amount of egg lay observed in many area fields. This may be because the large number of newly emerged females has been more attractive for males than our pheromone traps.

At this point in the season pyrethroids have generally been the product of choice for bollworm control. The following is a list of suggested products.

Cotton aphid populations are not much higher than last week, but after pyrethroid applications we could see a rapid increase. Also the cool cloudy conditions could contribute to an aphid increase. Lady beetles have been abundant where aphid populations have been high and may reduce numbers before economic damage occurs.

Beet armyworm infestations continue to be found scattered over the area. Egg masses have been commonly found in the Cotton Center area. Because of increased beet armyworm activity the Texas Boll Weevil Eradication Foundation adjusted the boll weevil treatment threshold to treating only 40 acres in a field catching one or more weevils for the southwestern area of Hale County.

For the week ending on August 4, only 7,900 acres were treated in the Northern High Plains zone, for a total of 109,487 cumulative acres this year.

Whiteflies are increasing in some area fields and immature stages can be seen on the underside of cotton leaves as small, light colored, flattened, oval shaped structures attached to the leaves. Do not confuse these immatures with bollworm or looper eggs since they are the same size.

CORN

Southwestern corn borer trap collections are once again on the increase at several locations. Fresh egg lays were found last Friday in the Earth area by IPM- Agent, Emilio Nino. Late planted corn or corn to be harvested late should still be scouted for this pest.

Banks grass mite samples were collected from 3 fields in Hale County and 2 fields in Swisher County and sent to West Texas A&M University to be evaluated for resistance levels to bifenthrin (Capture). Robert Bowling , IPM Agent and Dr. Bonnie Pendleton are coordinating this project. We have had no fields treated in-season for spider mites this year; therefore we have had no mite control failures reported to date.

Most fields have now had Banks grass mite infestations stabilized by beneficials. Predators commonly found have been cecidomyiid fly larvae, spider mite destroyer beetles, pirate bug nymphs, predatory mites and six-spotted thrips. Where the six-spotted thrips have been found the mite colonies have collapsed. The damage on the leaves is visible but no mites can be found. Keep a close watch on these predators, they may eliminate your mite problem.

SORGHUM

Sorghum midge infestations remain variable with counts ranging from 1 per 20 heads to 1 per head. This pest must be scouted for daily during the bloom period, since populations can greatly vary from day to day.

This is one case where growers must assist their consultants since they are usually on a weekly inspection schedule.

Headworms are also on the increase. Both fall armyworm and corn earworms have been found feeding in the head. In many cases the beneficials have helped to hold these populations in check, but as egg lays increase the beneficials may not be adequate.

 

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

---

Posted at this web site by:
texagnet Internet Services.