Pest Patrol: Southeast

Blake Layton, Extension entomology specialist at Mississippi State University, mentions three pests - stink bugs, corn earworm, and pea curculio - in particular, that are a problem for growers in his state. Stink bugs, he says, are arguably the leading insect pest in Mississippi because they occur on so many different crops, including southern peas and tomatoes.

"Control largely depends on spraying regularly with pyrethroid insecticides when stink bugs are present," explains Layton. "Destroying old plants as soon as the crop is finished is an important cultural control because it prevents large numbers of immature stink bugs from becoming adults and moving to adjacent crops. Vegetable growers also need to be aware of the status of row crops in their area because large numbers of stink bugs will migrate from crops such as corn, sorghum, and soybeans when these crops mature."

Next on the list is corn earworm. Layton says Mississippi has little commercial sweet corn production in the mid-south, but earworms have to be managed intensively on the acreage that is present, as they also infest major row crops.

When corn earworms are present in tomatoes they are called fruitworms. Tomato fruitworms are a threat all season, but growers with late-season crops can expect especially heavy infestations, he says.

"Fortunately, the pyrethroid insecticides will control both fruitworms and stink bugs," says Layton. "There are several alternative, non-pyrethroid products that are also effective against fruitworms but do not control stink bugs. Radiant (spinetoram, Dow AgroSciences), Coragen (rynaxypyr, DuPont Crop Protection), and Avaunt (indoxacarb, DuPont Crop Protection) are three examples."

The third pest plaguing growers in this area of the country is cow pea curculio. Specifically, it is a key pest of southern peas. Layton explains the damage this pest causes: "This small gray weevil chews through the pod wall and lays its eggs in the developing seed, resulting in pimple-like "stings" on the outer pod wall and the seed inside. The eggs hatch into legless grubs, which develop inside individual seed. Adult curculios are rarely seen because they quickly drop from the plant when they sense any disturbance. Stink bug damage is often confused with curculio damage, but the feeding spots are smaller, more like a pin prick, and stink bug damaged seeds are often shriveled."

The adult cowpea curculios can't damage peas until pods are large enough for them to lay eggs in, he says. The objective is to control adults that have migrated into the field before they have a chance to lay eggs, Layton explains. You can achieve this by applying a series of three sprays at five day intervals, beginning as soon as you see the first 1/2 inch long pods.

The Sunshine State

In Florida, whiteflies are the enemy, says Gene McAvoy, regional vegetable agent IV, University of Florida, Institute of Food And Agricultural Sciences. A major pest of tomatoes and cucurbits, whiteflies transmit the tomato yellow leaf curl virus (TYLCV) and vine decline - tolerance is zero, says McAvoy.

"Scouting is extremely important for early detection," he says. "Many growers are using reflective mulches and some are planting TYLCV-resistant cultivars in spring when whiteflies tend to be worse in South Florida."

McAvoy says a range of materials can be used on whiteflies, beginning with soil-applied nicotinoids, such as Admire (imidacloprid, Bayer CropScience), Platinum (thiamethoxam, Syngenta Crop Protection), and Venom (dinotefuran, Valent). Typically, those products are followed by insect growth regulators and other products such as Oberon (spiromesifen, Bayer CropScience) and Fulfill (pymetrozine, Syngenta Crop Protection), as well as soaps and other adulticides.