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Texas Agricultural Extension Service The Texas A&M University System Plains Pest Management Newsletter |
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News about Integrated Pest Management in Hale-Swisher Counties. Greg Cronholm, Extension Agent - IPM, 122 East 6th, P.O. Box 680, Plainview, TX., 79073-0680, 806-291-5273 |
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Web Site: http://entowww.tamu.edu |
E-Mail:
g-cronholm@tamu.edu
July 12, 2001 |
Cotton continues to look very good where irrigated. One crop consultant reported seeing blooms on June 28 in April planted cotton. Late April to early May planted cotton began blooming from July 5 through 9th. Most fields not blooming now should have blooms early next week. Cotton fleahoppers
and Lygus bugs continue to be the most common pest in area cotton.
Adults and nymphs of both plant bug species have been reported, indicating
within field reproduction. Most fields have had an equal split between
cotton fleahoppers and lygus bugs. Our % squares sets have gone up compared
to previous weeks, generally in the 83 to 97% range. One reason is that
plants have grown and crab spiders have reduced nymphal populations
of plant bugs. Most fields now have 0.2 to 1.0 plant bug per foot of
row. As fields reach the bloom stage we generally consider cotton fleahoppers
not to be a problem unless populations are very high. The " Lygus
bug complex" is a different matter since they damage all sizes
of squares, blooms and small bolls. Cotton aphids have been observed in many fields, but have remained below treatment thresholds due to ladybeetle larvae and syphid fly larvae. |
Beet
armyworms and cotton bollworms continue to be found in light
numbers. Many of the beet armyworms have been parasitized by small wasp.
Hopefully these parasites will help us as we progress in the season.
Cotton boll weevil trap collections remain very low across the area. Usually from the 1/3 grown square stage to bloom stage traps are no longer an effective tool. This is because the squares and blooms are more attractive to the weevils. Also when we move into the bloom period overwintered emergence is complete and movement into cotton has stopped. Management decisions should be based on percent punctured squares during the 1/3 grown square stage to approaching cut-out or when square densities fall below boll densities. It is best to examine 100 1/3 grown squares and inspect them for feeding and egg laying punctures. Prior to peak bloom, treatment may be justified if 20% of squares examined are punctured by weevils. After peak bloom the threshold goes up to 25 or 30 % of the squares examined having weevil punctures.
Corn ranges from green silk to soft dough stage. Many fields are in the blister or roasting ear stage. With the dry conditions corn is beginning to show some signs of stress. Colonies of Banks grass mites have been easier tolocate this past week and are mostly found in drought stressed areas in the field. |
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Southwestern corn borer eggs have been reported, but we are still very early in the emergence period for 1st generation moths. Two fields in the Edmonson and Hart areas were inspected on Tuesday July 10. The following results were found.
The model prediction for the Edmonson field sampled indicated that 25% emergence would occur on July 11. It appears that our model will be very close to that observed in the field again this year.
Green bugs continue
to increase in area fields. Damage is spotty in the field and has been
confined to lower leaves. Predators have reduced corn leaf aphid populations
and may help us with greenbug infestations. Also, a few parasitic wasp
"mummies" have been reported in greenbug colonies from several
fields, which is a very good sign help is on the way.
Some fields have now completed the bloom period and should be safe from sunflower moths, while other fields are just now starting to bloom. Those blooming now should be scouted for presence of sunflower moths so that timely applications can be made if this pest is present.
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We continue to have reports of fields, homes and businesses being invaded by hoards of false chinch bugs. It is often necessary to treat a large barrier around the location to be protected. Usually two airplane swath widths into the pasture or CRP where these bugs are migrating from can reduce the infestation and nuisance factor.
Sincerely, Greg Cronholm  Posted at this web site by: texagnet Internet Services.
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