Cotton Pest Management Newsletter #3
June 7, 2001

Cotton Situation: The Georgia Weekly Weather and Crops Report for the week ending June 3^rd listed the crop as 90 percent planted and 9 percent squaring. These estimates are slightly below the five year averages. Much of the state received beneficial rainfall, but some areas remain dry.

Insect Situation: Thrips numbers appear to have peaked during early and mid-May as pressure has lessened during recent weeks. Much needed rainfall has enhanced seedling growth and uptake of at-planting insecticides which also helped reduce seedling injury from thrips. False chinch bugs (nymphs and adults) are numerous in some reduced tillage fields. Low numbers of TBW eggs have been reported on a few early planted fields. Beneficials are becoming established in fields at this time. Big-eyed bugs are numerous in fields I have visited.

Beneficials Building: During the past week, we have conducted several scouting schools in various parts of the state. As part of the training, we have visited early planted fields to teach scouts about plant growth and development as well as insect identification. Numerous beneficial species such as big-eyed bugs, pirate bugs, scymnus lady beetle adults, nabids, hooded beetles, fire ants, and various spiders have been observed in the field. Broad spectrum insecticides should be avoided since this is the time of year when beneficials are becoming established in fields. The disruptive nature of broad spectrum insecticides will be noticeable in upcoming weeks in fields where these products are used. If an insecticide is needed for control of tobacco budworm or other insect pests, a selective insecticide should be used so that natural enemies are conserved.

Big-eyed Bugs: Big-eyed bugs are considered by many to be the most important predator which inhabits cotton fields. Adults and nymphs are important predators of many cotton insect pests including tobacco budworm and corn earworm eggs and small larvae, whiteflies, aphids, mites, and even plant bugs. In the absence of prey, big-eyed bugs will sustain by feeding on cotton nectar and occasionally plant sap. This limited plant feeding does not damage plants. Adult and nymph big-eyed bugs are easily recognized by their large bulging eyes. There are two species of big-eyed bugs found in Georgia cotton. Geocoris punctipes is the most common species. Adult G. punctipes are 3/16" in length and silvery gray in color. Geocoris uliginosus are slightly smaller and less common in Georgia. Adult G. uliginosus are 1/8" in length and black to reddish black in color. Nymphs of both species look like small adults but lack wings. Big-eyed bug eggs are grayish white to pink in color and are hot dog shaped. Eggs are deposited individually and are easily seen on terminals, leaves, and stems. Eggs will hatch in about a week and nymphs will complete development in about 3 weeks. Each female will produce 150-300 eggs and live 3-4 weeks. Scouts should pay close attention to this "need to know" predator.

Tobacco Budworm: To date few reports of tobacco budworm (TBW) have been received. Scott Brown, CEC Colquitt County, reported low numbers of eggs early this week. Eggs are most likely to be observed on older squaring cotton but may also occur on pre-squaring cotton. David Jones, Extension Entomologist, observed light to moderate infestations of small TBW larvae on tobacco this week also. Scouts should be observant for eggs and small larvae in upcoming days. Hopefully predators can suppress populations below economic levels if infestations materialize. If insecticides are needed, selective chemistry should be used. Bt cotton should provide excellent control of TBW.

Plant Bugs: Treatment decisions for plant bugs should be based on several factors including small square retention, plant bugs observed in the field, total fruit set, and variety. Insecticide may be warranted if square retention rates are below 85 percent and declining, and numerous plant bugs or cotton fleahoppers are observed in the field. Plant bug insecticide applications will reduce beneficial insect populations and this decline in natural control must be considered. Growers should be very cautious when considering treatment of non-Bt cotton for plant bugs since problems with tobacco budworm and corn earworm may be exacerbated due to reduced beneficials.

False Chinch Bugs: False chinch bugs are numerous in some reduced tillage fields. If seedlings have not attained five true leaves and are growing rapidly, severe infestations of false chinch bugs could reduce stands. No insecticides are labeled for false chinch bug control in cotton, but a high thrips rate of Bidrin, dimethoate, or Orthene should provide suppression.

Scout Schools: June 18, 2001 Burke Co. (Midville)

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."

Next Newsletter: The next newsletter will be written on June 21, 2001.

Sincerely,

Phillip Roberts
Extension Entomologist