Some cotton insect pests never seem to disappear. They might go away and hide for a while, but they also find a way to make encore appearances every year.
Such is the case with many troublesome insects across the Belt. Their numbers might fluctuate in any given year, but they are still on the radar screen.
Cotton Farming contacted an entomologist in each major production area to gain a broad overview of the kind of insect pressure that might confront producers this year.
Here’s what they had to say.
Any discussion of cotton insect pest pressure in 2011 is overshadowed by the record-breaking floods brought on by the Mississippi River.
Many cotton acres will be abandoned as producers wait for floodwaters to recede. However, even with the floods, some trends never change in Missouri, Tennessee, Mississippi, Arkansas and Louisiana.
Tennessee Extension entomologist Scott Stewart says the plant bug will always be at the top of the list no matter what the weather conditions are.
“I think the plant bug is still our top insect threat for the Mid-South,” he says. “Historically, when we’ve had wet springs, the plant bug outbreaks tend to be at their worst. And when you combine that fact with a late-planted crop, it can add up to a bad situation.”
Stewart says producers now know more about the plant bug’s biological profile and how much the cotton plant can tolerate this pest. But it’s difficult to control a pest that thrives in wild host environments before it migrates into cotton fields.
Another factor is complicating Mid-South producers’ plans for controlling this pest. So much time and energy are being spent on combatting the glyphosate-resistant pigweed outbreak that budgets aren’t allowing for necessary insect control.
“A farmer can sometimes overlook these insect problems,” says Stewart. “It all depends on the farmer and whether he has a professional crop consultant. Many times a producer will concentrate on another problem, like pigweeds, and overlook plant bugs.”
Compounding the problem even more is that pigweeds are excellent wild hosts for plant bugs.
“It’s a double whammy,” says Stewart. “If you want to find the plant bugs, go look for the pigweeds.”
Data from the Cotton Insect Losses 2010 report, compiled by Mississippi State University entomologist Michael Williams, indicate that the stink bug was the most damaging insect pest in Tennessee, followed by plant bugs and spider mites. Stewart, however, still puts the plant bugs at the top as far as being the cotton insect pest that concerns him the most.
“You just can’t afford to make early season mistakes with this pest,” he says.
A scorching drought in this region is affecting all parts of cotton production in Texas, Oklahoma and Kansas. It certainly has had a direct impact on the kinds of insect pests that will affect Texas, the largest cotton production state in the Belt. No significant rainfall has occurred in the state since last fall, and wildfires have broken out numerous times during the last few months.
Texas AgriLife Extension entomologist David Kerns says the fleahopper continues to be the major insect pest in the eastern part of his state, including the coastal and central areas. Thrips and bollworms also are high on the list.
“I don’t know what we’ll see because it’s so dry across the state,” he says. “Year in and year out, this situation hasn’t changed much. The fleahopper is usually our top pest.”
Because Texas is such a large state, insect behavior can vary between specific regions. For example, despite the presence of fleahopper outbreaks throughout Texas, the major pest in the western part of the state is actually thrips.
The record-breaking drought is also having a direct impact on which insects will have more populations. Because fleahoppers don’t have weed hosts on which to feed, their populations may be lower.
Making insect strategies even more challenging is the different behavior of the fleahopper in east and west Texas. In the east, this pest tends to be more damaging to cotton and will require at least two or three sprays. In the west, according to Kerns, the levels of infestation aren’t nearly as severe. One application is made and “then you’re out of the woods.
In the Coastal Bend and central Texas, a residual application is usually required to deal with fleahoppers.
Despite the differences in the various production environments in Texas, Kerns says the dry weather may contribute to an outbreak of spider mites in some parts of the state.
An outsider might think that because of similarities in soil profiles, cotton insect pests in the Southeast would resemble the Mid-South. But, that isn’t necessarily the case.
While there are wide differences in production environments among Virginia, North Carolina, South Carolina, Georgia, Alabama and Florida, the No. 1 insect pest in the region continues to be the stink bug.
Research Extension entomologist Jeremy Greene, based at Blackville, S.C., says that stink bugs have been in the top pest group for several years followed closely by thrips and bollworms.
“Our insects over here have a lot of different wild and cultivated hosts,” he says. “Plus, our field sizes are relatively small and surrounded by woods, essentially providing a larger field border area where insects typically are more of a problem.”
Greene also believes that moving cotton into new acreage can present some unusual challenges. For example, if a field previously was in pasture or turf, problems with insects, such as cutworms, can show up when cotton is planted.
The consensus in California, Arizona and New Mexico is that Lygus will continue to be the top cotton insect pest in the western part of the Belt. This pest, also known as the western tarnished plant bug, has been around since cotton was first grown in the region.
Secondary pests, such as mites, thrips, whiteflies and aphids, certainly have their place in the pecking order, but none is likely to overthrow Lygus as the worst pest in the West.
What makes Lygus so hard to control is their inconsistent behavior. Rodney Cooper, California Research Entomologist with USDA-ARS in Shafter, says Lygus can cause serious damage to cotton plants – regardless of whether they are treated.
“A lot of factors influence the Lygus behavior in California,” says Cooper. “We have had a wet spring, and that obviously builds up the natural vegetation in the field.
“The Lygus populations feed on this vegetation. Then, they move into crops such as cotton. It’s a difficult pest to understand, and it isn’t going away anytime soon. It feeds on every kind of plant out there, and you never know how often to spray for it each year.”
Contact Tommy Horton at (901) 767-4020 or firstname.lastname@example.org.