Recent flooding along Arkansas rivers is likely to result in a flood of insects affecting major crops and people living in communities near flooded areas, say extension experts with the University of Arkansas Division of Agriculture.

Dr. John Hopkins, extension urban entomologist, said populations of black flies and mosquitoes could thrive in flooded areas and pester people in nearby communities.

Meanwhile, major delays in planting crops caused by the flooding could set farmers up for big insect problems in late summer, said Dr. Gus Lorenz, extension entomologist with the University of Arkansas Division of Agriculture.

“We’re seeing major planting delays. By this time in most years, we’re through planting rice and corn, almost through with soybeans and heavy into cotton,” he said.

“Farmers like to plant many crops early in the season to avoid late-season insects. I’m afraid the flooding is going to set us up for potential late season pest issues, especially in corn, cotton and soybeans,” Lorenz said.

Many problem insects migrate into Arkansas late in the season from the south, so the later farmers plant, the greater the opportunity for late-season insects to become established, as crops are beginning to mature. If crops are mature when insect infestations occur, the risk of yield loss is greatly lessened.

Last year, Lorenz recalled that farmers avoided a lot of bollworm problems in cotton because they were able to plant early. Many farmers escaped having to treat for bollworms.

The entomologist said if certain environmental factors fall into place this year, late-season plant bugs and fall army worms could wreak havoc in cotton. In soybeans, loopers and plant bugs will be hard to deal with, he said.

“The later we plant rice, the more subject we are to problems with rice water weevils,” he said.

The problem could be worsened if Arkansas experiences a dry July and August. He said caterpillar pests thrive in dry conditions.

“Generally, when we get too much rainfall early,"Lorenz said, “we’re going to pay for it later on when it gets dry.”

Lorenz said it’s not all doom and gloom.

Flooding may have reduced populations of some pests. Stemborers in soybeans grape colapsis in rice may be seriously impacted in some flooded areas. He said the insects overwinter in the soil or debris that has been covered by water for an extended period of time.

“Budworms and bollworms overwinter in the ground too,"Lorenz noted, “but it’s their migrating cousins that could cause the problems.

“We may see a mixed bag of insect problems, with some areas lighter than normal and some heavier than normal. It’s not as clear cut as you would think,”
he said.

Hopkins said mosquitoes will breed in the many stagnant pools left behind by the flooding. Black flies breed in moving water.

“There’s little anyone can do about controlling biting black flies. All you can do,”
he said, “is protect yourself from bites by wearing long-sleeve shirts, hats and insect repellents containing DEET or picaridin. Avoidance is another option. Black flies usually don’t enter buildings in large numbers and feed ONLY during daylight hours.

Adult black flies, he noted, usually live from two to three weeks and peak occurrence in Arkansas is in the spring.

“Mosquitoes are a problem from spring until the first freeze,"Hopkins said. “Not only are they nuisance biters, but they can transmit various diseases, notably West Nile virus. The same precautions used against black flies should help prevent mosquito bites.”

For more information about insects in your area, contact your county extension agent or visit http://www.uaex.edu and select “Agriculture,” then “Ask the Pest Guys.” The Cooperative Extension Service is part of the U of A Division of Agriculture.

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