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Persistent Plant Bugs Won’t Go Away

persitantplantbugs Every cotton insect pest has its own calling card. But when it comes to unpredictability and consistent threat potential, the plant bug is in a class by itself. Maybe that’s why it continues to be a nemesis for cotton production.

The numbers tell the story, according to Mississipi Extension entomologist Mike Williams’ 2013 Cotton Insect Loss Estimates report.

Here was the impact (in bales lost) in the Mid-South where this pest continues to cause damage: Arkansas – 49,467 bales. Louisiana – 15, 985 bales. Mississippi – 45,378 bales. Missouri – 29,095 bales. Tennessee – 21,189 bales.

“This pest isn’t going away,” says Tennessee Extension entomologist Scott Stewart. “It’s anybody’s guess as to when we’ll have bad years. But the reality is that it has become a serious early season and mid-season pest for cotton.” Even though cotton acres are slightly up in the Mid-South this year because of excellent yields in 2013, the plant bug still persists – and overall acreage is considerably less compared to several years ago. Therein lies one of the problems in combatting the insect. According to Stewart, the less acreage planted, the greater the concentration of plant bugs. “These pests just wind up in the pure cotton acres,” he says. “With increased cotton acreage this year, maybe the problem won’t be as severe.”

Importance Of Management

One fact is clear. When managing a key pest, it influences all other decisions. That is why entomologists say it’s crucial that producers sample their fields and understand the scope of the infestation, if the problem even exists.

Stewart says plant bugs sometimes are difficult to understand, and the entire process can resemble putting together a puzzle. Entomologists try to make predictions, but their best hope for the future might lie in new lygus Bt traits that could be part of future cotton varieties. “These things could become commercially available,” says Stewart. “My guess is that this will happen in three to five years. They show a lot of promise.” For the moment, the task confronting producers is knowing that there is a lot of variability in the plant bug problem. These pests are unpredictable and don’t infest every acre.

As Stewart points out, if they hit every acre at the same time, they wouldn’t be hard to manage.

Unpredictable Pest

persistent plantbugsIt is the uncertainty of plant bug outbreaks that apparently bothers producers the most. That’s why Extension entomologists recommend a workable budget for dealing with the problem. “You have to put up a good fight,” says Stewart. “With most fields, we are talking about two to three critical sprays during the season. “And I can’t emphasize enough how important it is to time these sprays accurately. If you’re late, that isn’t good. If you’re early, you miss them. It all comes down to information.”

There is also the temptation to manage plant bugs in a manner similar to controlling resistant pigweed. Adopting a “start clean, stay clean” approach would be wrong. Stewart says such an approach sends the wrong message to farmers. A zero tolerance for plant bug infestations isn’t necessary. Stewart has seen plenty of fields with sub-threshold numbers all year long, and yields aren’t affected. As mentioned earlier, insecticide selection and timing of the application are the crucial decisions. And, in West Tennessee, factors such as field variability, planting dates and varieties can figure into the severity of a plant bug infestation.

“Nothing shocks me anymore,” says Stewart. “When we eliminated the boll weevil, there was a vacuum, and something will always fill it, and this time it was the plant bug. “We have made progress, and we aren’t spraying as much. When we were dealing with the boll weevil, you were guaranteed to need four or five sprays to clean it up. On plant bugs, you might have to hit it hard a couple of times.”

Prepare For The Worst

Two of Stewart’s West Tennessee friends – consultant Tim Roberts and producer John Lindamood – have had plenty of experience in dealing with plant bugs. Both are hoping for the best but also are bracing for unexpected outbreaks. They are hoping that a cold winter will help in decreasing plant bug populations, but it’s still too early to know if that will happen.

There is also the fact that the current crop is off to a late start. That might mean fewer native host environments for the plant bugs. “We might be able to beat them to the punch,” says Roberts. “My consultant friends believe if you keep them out of the field during the first month of that fruiting period, you have gone a long way toward keeping them from eating you up.” Roberts says plant bug “blowups” can occur at any time, and that is why it is essential to spray early. “Just don’t ever get behind,” he points out.

06-14CFcvr“If you do, you’re sunk. You can still make a crop, but you’ll wind up pumping more money into it.” Roberts likes to tell his producers to “hit them early and often. Watch your costs because the days of the five-dollar plant bug shot are gone.” Being Proactive Helps From a producer’s perspective, it’s all about rotating chemistries and using every available tool to fight plant bugs. And this is the approach Lindamood is using this year. He farms in the extreme northwest corner of Tennessee in Tiptonville.

Currently, he is concerned that the Environmental Protection Agency (EPA) might restrict the use of neonicotinoid insecticides specifically targeted for plant bugs. If that happens, he can envision potential infestations of spider mites and aphids caused by broad spectrum applications from other insecticides. Lindamood also sees the advantage in sequential applications. In other words, it’s better to make a second application in five or six days as opposed to waiting 10 days. “You stand a better chance of putting a lid on these pests when you come back quicker with that second application,” he says.

If that sounds like a quick turnaround, he says it’s better than waiting too long and facing a third and fourth application 10 to 20 days later. This approach also reduces the overall amount of insecticides applied. “I can tell that this problem has increased in the last few years,” says Lindamood. “We’re spraying more for plant bugs, and I just hope that we aren’t looking at any kind of resistance as we look to the future.”

Contact Tommy Horton at (901) 767- 4020 or thorton@onegrower.com.