Rains during the last two weeks have improved yield prospects, but it
was too late for some dryland fields. Some areas are still dry and sustained moisture is needed. Open bolls have been observed in a few early-planted fields. INSECT SITUATION:
Reports of stink bug numbers and boll damage increased this week. We would expect stink bugs to be a primary pest for the remainder of the season. Corn earworm and tobacco budworm populations vary significantly
across the state. Pressure ranges from light to heavy and species makeup of infestations is a mixed bag. Armyworms, both fall and beet, are generally light but sporadic.
Bt cotton / Corn Earworm:
In parts of the state, Bt cotton is being treated for corn earworm (CEW). Scouts should pay close attention to blooms and bloom-tagged bolls. Eggs have been observed on square bracts and dried blooms in some areas. When examining bolls with stuck bloom tags, be sure to examine under and in the bloom itself for CEW larvae. In some situations, small larvae will be observed feeding in the top of the boll, actually penetrating the boll. In some areas, heavy corn earworm egg lay has occurred and producers should be prepared to treat. Last year, relatively few Bt fields required supplemental treatment for CEW, but we know treatment may be needed in certain situations.
Tobacco Budworm and Corn Earworm: Species makeup of the "bollworm complex" varies from field to field. Insecticide selection is extremely important when tobacco budworm (TBW) is the predominant
species and pyrethroid resistance is a concern. In most fields, mixed populations are being reported. These should be treated as TBW if that proportion of the complex makes up an economic population. For example,
if you think the infestation is 50% CEW and 50% TBW and 30 small larvae are found per 100 plants, we would estimate a TBW count of 15 small larvae per 100 plants which is above threshold. Timing of sprays is extremely
important on non-Bt cotton.
Armyworms: Fall and beet armyworm infestations are light to moderate but sporadic. Scouts should be observant for egg masses. We would suggest periodically bending
plants over and looking at the underside of leaves for egg masses. Small falls disperse upon hatching and will initially feed in blooms or on the inner surface of boll bracts. Early detection is key for efficient fall
armyworm control.
Stink Bugs: Be sure fields are being monitored for stink bugs. Fields which have not been treated with an insecticide that has activity on stink bugs (such
as a pyrethroid), are most likely to need treatment.
Silverleaf Whitefly: Recent showers have helped suppress whitefly numbers. However, this pest should be watched closely, especially in the
Omega vicinity. Compared with last year, numbers of silverleaf whitefly are significantly less.
INSECT UPDATES: Check the Cotton Insect Hotline
(1/800-851-2847) for updates on current insect conditions. The Cotton Pest Management Newsletter is also posted on the Internet at "www.gaipm.org" and then click on "cotton."
Sincerely,
