Insect pest situations developing now

The environmental conditions the Delta experiences over the next six weeks will determine the pest densities seen this growing season, says Ralph Bagwell, Louisiana Extension entomologist.

“At this point (in early April), it's really too early to determine what to expect. We'd certainly prefer a low pest year, but up front we just can't tell those kinds of things. We should have a better handle on pests by mid-May.”

Louisiana's winter was average — it wasn't exceptionally cold and there were no ice events. But most of the insects Louisiana growers deal with in cotton now — with the obvious exception of boll weevils — aren't affected by overwintering anyway. It's actually an oddity to have a winter storm event that will knock boll weevils back in the state, says Bagwell.

“If farmers will slow down and do everything properly up front, it'll save them time and costs later on,” says Bagwell. “We always have a preference for an at-planting treatment for thrips control. We generally see that makes a significant impact on late season insect treatment costs.”

In Arkansas, Gus Lorenz, Extension entomologist, says it appears that, “we're getting a fast start with the growing season and aphids on corn.”

It appears that the aphids producers are seeing are bird cherry oat aphids. These aphids aren't considered a major pest of corn, but the numbers are “extremely high” on seedling plants.

“They're hitting the plants as they emerge,” says Lorenz. “The aphids don't appear to be doing a whole lot of damage. However, coupled with the cold temperatures we're experiencing, what damage they're doing is potentially magnified. If farmers start seeing wilted plants, leaves browning and things like that, they should consider treating — most suitable products would be pyrethroids.”

The fact that bird cherry oat aphids have shown up in such high numbers is not an indicator that the typical, voracious aphids producers are so familiar with will soon arrive in large numbers, too.

“Aphids move in from different areas and this doesn't tell us one way or the other that aphids will be a problem later in the season.”

Bill Robertson, Arkansas Extension cotton specialist, says he's heard several state entomologists talking about tobacco budworms being their top concern going into the season.

“If conditions are right, because we put so many up last fall, the numbers will be there,” says Robertson.

Lorenz agrees. “The producers in northeast Arkansas — the folks who experienced heavy budworm pressure last growing season — need to keep a sharp eye out for budworms. A lot of the budworms overwintered up there. It's hard to say what the survivability was, but we certainly put a lot to bed, and they aren't migrators. That means there's an increased potential for budworm problems around Clay, Green, Poinsett and Mississippi counties.”

Lorenz also says following winters like the one we just experienced — colder compared to recent years — seems to favor plant bugs.

“After such winters, it seems we often see plant bug numbers spike. We should watch our cotton crop closely for plant bugs.”

This is obviously speculation, though, warns Lorenz.

“I have no crystal ball — and it seems every time I make a prediction it's wrong — but these are the things I'd watch for. I do know that the tick populations are bad this year. The infestation is extremely high. Ticks aren't affected by cold winters — they're native pests and cold weather doesn't knock them back like it will non-native species like boll weevils. Keep the bug spray handy.”

e-mail: [email protected].

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