What is in this article?:
• Soft insecticides can provide good insect control and spare beneficial insects that can create an overall excellent insect management program in vegetable crops in the Southeast.
• Beneficial insects fit into IPM (integrated pest management) programs nicely and they can help significantly with insect management.
• In some situations growers can get comparable insect control from a soft insecticide plus beneficials versus using a broad spectrum insecticide that kills the good and the bad insects in a field.
CLEMSON ENTOMOLOGIST Powell Smith says soft insecticides and beneficials can keep insects under control in brassica vegetable crops.
May disrupt head formation
Although the larvae are very small, they can be quite numerous, resulting in complete removal of foliar tissue except for the leaf veins. This is particularly damaging to seedlings, and may disrupt head formation in cabbage, broccoli, and cauliflower.
This is particularly troublesome for the Southeast’s burgeoning broccoli production. The presence of larvae in florets can result in complete rejection of produce, even if the level of plant tissue removal is insignificant.
Cabbage loopers are the largest of these three insects and they can eat a large area of foliage in a short period of time. They show up sporadically in fields in the Southeast and over the past few years have been more of ‘then’ not ‘now’ problem in commercial production, the Clemson vegetable expert says.
He says cabbage loopers are not only the largest of the three insects that cause problems in brassica crops in the Southeast, but it’s also the hardest to kill.
Cabbage loopers feed on a wide variety of cultivated plants and weeds. As its common name implies, it feeds readily on crucifers, and has been reported damaging broccoli, cabbage, cauliflower, Chinese cabbage, collards, kale, mustard, radish, rutabaga, turnips in the Southeast.
Other vegetable crops injured include beets, cantaloupe, celery, cucumbers, lima beans, lettuce, parsnip, peas, peppers, potatoes, snap beans, spinach, squash, sweet potatoes, tomatoes, and watermelons.
Additional hosts are flower crops such as chrysanthemum, hollyhock, snapdragon, and sweetpea, and field crops such as cotton and tobacco.
The high risk of damage from these insect pests, combined with their sporadic occurrence, make them ideal candidates for a combination of soft insecticides and IPM programs.
Allowing naturally occurring beneficial insects to help in controlling these pests is a win/win situation for commercial producers and home gardeners alike, Smith says.
With adequate scouting and using thresholds, vegetable growers in the Southeast can eliminate a number of sprays and still achieve good control.
It’s no longer a given that crops, like collards, have to be sprayed every week to insure a marketable crop at the end of the season, he adds.