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COTTON PEST MANAGEMENT NEWSLETTER #4 June 23, 2000
COTTON SITUATION: The Georgia Weekly Weather and Crops Report for the week ending June 18th listed the crop as 45 percent squaring and 9
percent setting bolls which are similar to the five year averages. Thirty-nine percent of the crop is listed in poor to very poor condition. You drive for show and putt for doe.INSECT SITUATION:
The insect situation has been relatively quiet in recent days. The first generation of tobacco budworm is over in most areas and scouts should be observant for the second generation of tobacco budworm in southernmost
counties this week. A few isolated problems with square retention have been reported. Big-eyed bug populations remain high. Aphid numbers are building in some fields. Tobacco Budworm: Very few fields required
treatment for first generation tobacco budworm (TBW). It does appear that the first TBW flight is over in most parts of the state. In some areas it was difficult to pinpoint an exact date of when or if the flight
occurred but scouts in southernmost Georgia should be observant for increased moth activity and egg lay in the next few days. Typically the second generation or early July TBW flight is when pressure intensifies. We
would expect the majority of eggs and larvae found this week to be TBW. Bt cotton should provide good control of TBW. On non-Bt cotton, growers must react quickly based on scouting reports. Preferably action
should be taken within 24 hours. Timing of insecticide applications is critical for success. In areas where pyrethroid resistant TBW is a concern, alternative chemistry should be considered. Aphids:
Aphid infestations are continuing to increase. In most situations, only isolated spots in fields are infested, however, populations will soon disperse and infest entire fields. Plant Bugs: Scouts should be observant for
tarnished plant bugs and cotton fleahoppers in squaring cotton. Square retention counts should be continued into the second week of bloom. Be sure not to confuse plant bugs with false chinch bugs.
Beet Armyworm:
Fortunately, we have not experienced major problems with beet armyworm (BAW) in recent years and thus many new scouts may not be familiar with this troublesome pest. BAW is a dry weather pest and our conditions meet that criteria. BAW is also much more likely to occur when beneficials have been disrupted. Fortunately, good numbers of benes are present in most fields at this time. Beets can infest cotton at any age or stage from seedling to cut-out. They are primarily foliage feeders and complete a generation about every 3 weeks. Eggs are laid in masses or clusters on the undersides of leaves. Upon hatching, small larvae feed in a group on the underside of the leaf, leaving the upper leaf surface intact. This creates a "windowpane" effect that is referred to as a "BAW hit". Beet armyworm infestations or BAW infestations
should be reported as number of active hits per 300 row feet. If a suspected hit is observed, examine the underside of the leaf for the presence of larvae. If none or only a few larvae are observed, predators
more than likely reduced or controlled the BAW. 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, Phillip Roberts
Extension Entomologist |
