Plant bugs have record year in cotton

They were here, they were there, they were all around.

Mangled rhymes may not be a conventional mode of detailing cotton conditions, but considering the rampant infestation of plant bugs in Delta fields, convention is not what is needed to combat the pests.

Participants attending the recent field day at the Brooks Aycock Farm near Belzoni, Miss., were given an update on the intense pest pressure, and offered several potential preventive measures that may be employed in the future.

Angus Catchot, Mississippi State Extension entomologist, detailed the scope of the plant bug spread. “I have never seen it like this, at least to this extent — the plant bug situation was extremely bad in areas of the Delta.

“This is no doubt going to be a record year on plant bug sprays that we make. Some of our early survey work suggests that we could easily exceed seven applications for an average in the Delta this year, and some areas had 15 applications. Prior to this year the record number of sprays was 5.2 in 2004.

“In our Stoneville cotton plots, we came out of the gate this year and by the time we put the first square on the cotton were averaging about 30 percent plant bugs. We made the application, we came back the next week, square retention went down, and plant bug numbers went to about 35 percent.

“We sprayed again and the next week, retention across the whole field dropped to 39 percent, and we were averaging 48 percent plant bugs. It was a continued migration into the fields. It was bad, and it stayed bad for a long time.”

After stretches of rain when crop dusters were backed up, and following a good deal of natural fruit loss, plant bug numbers moderated. Plant bug dormancy offered farmers false hopes that the infestation was in recession, but allowed producers to get back in the field on more a timelier schedule.

“We started getting questions just a little bit before cutting-out time. ‘What happened to the plant bugs?’ Well, they didn’t really go away. A lot of the drop was due to the dry period, and the fact that the cotton was cutting out and less attractive.

“We had a test in Stoneville on some late-planted cotton where numbers were dropping off in production fields, and we hit 91 plant bugs on just one drop. So they are still around, but isolated to the later-planted crop,” he explained. “We’ve got a lot of cotton this year that’s going to have up to 15 applications for plant bugs.”

Catchot said he’s consistently asked the same question by farmers: Why were plant bugs so bad?

Part of the answer is found in the increase of corn acreage. Precisely how big of a factor corn acreage is in regard to cotton plant bugs remains indefinite. However, it is undeniably a host of plant bugs, and Catchot believes corn is playing a heavy role in the plant bug infestation.

Catchot believes the unusually warm March weather allowed overwintering populations to build to extremely high levels. USDA-ARS scientists at Stoneville were collecting plant bugs in March on wild hosts, and were reporting a heightened level of bug reproduction.

“When we went through that little drought period early, there weren’t a lot of wild hosts, so we weren’t finding as many in the ditch banks. But at the same time, we were irrigating corn and early beans. We had no trouble finding corn and early beans just full of plant bugs.

“When the migration started moving into squaring cotton, we began taking counts in irrigated corn and Group 4 soybeans, and were finding extremely high numbers. So this big, early season population that blew up in March on wild hosts simply utilized corn and beans in the absence of abundant wild host plants. That’s how they maintained these extremely high numbers.”

Does he see a remedy for plant bugs in the near future? As with many ag questions, the answer is multi-layered.

“Next year, what are we going to see? We’re not going to see any big silver bullets on plant bugs coming from industry. I tried unsuccessfully this year on two Section 18s, but the EPA won’t allow either one of them. There are not a lot of new chemistries coming. We’ll have to work with what we’ve got, and begin to try to utilize other methods to try and put the odds in our favor.”

Farmers may not like Catchot’s lack of a silver bullet forecast, but he offered a composite approach to plant bug deterrence:

• Isolating cotton (separating cotton and corn acreage).

• Nectarless cotton (eliminating attraction to harmful insects).

• Plant bug management (controlling of wild hosts).

• Spraying (developing more effective products).

Despite the difficult plant bug conditions faced by Delta farmers in 2007, Catchot is hopeful of change. “All of these are things we need to think about in the future. Chemically, we are not getting it done under the pressure we faced this year. I think we’re going to get to the point where we’ll be able to start putting some of this into practice. Especially when we do things like isolate our corn acreage, and when companies release new nectarless cotton varieties that yield with current germplasm — or new types of spraying, and utilizing new sprayer technologies to maximize coverage.

“There’s a combination of things we can do to help that by themselves are not the answer, but when utilized in a fully integrated approach could offer growers some relief.”

e-mail: [email protected]

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