Angus Catchot, Extension entomologist for cotton and soybeans at Mississippi State University, knows cotton farmers may have names for spider mites that can’t be printed in a family newspaper or Web site.
“This is my term, but, if you grow cotton and you consult on cotton in some of these areas, I think you would agree with this statement wholeheartedly,” Catchot told participants in Cotton Incorporated’s Crop Management Seminar in Memphis.
“Spider mites, at least for the South or the Mid-South, are the insecticide budget-busters of cotton production. They are very expensive to treat. When we spray for spider mites, generally it’s with a material, either a miticide or an acaricide, that will only control one pest, spider mites.”
The Mississippi Cooperative Extension Service has not budgeted for controlling spider mites in the past because they have been sporadic or occasional pests of cotton, according to Catchot. But that situation is changing.
“In the last couple of years, we have increased the incidental pest column in our Mississippi State cotton budgets to reflect what we’re having to do with spider mites,” he said. “Our growers take them very seriously, and certainly our consultants take them very seriously because we’ve seen what they’ll do over the last couple of years.”
Catchot was one of a group of Extension, university, USDA and industry speakers who discussed insect management during the opening session of the Cotton Incorporated Seminar. More than 200 persons attended the event.
Until 2004, he noted, Mississippi cotton farmers rarely treated 100,000 acres for spider mites and those mostly in hot, dry years. In 2004, treatments for the pest jumped up over 100,000 acres. In 2005, the figure rose to 275,000 acres and, in 2006, to more than 400,000 acres.
“If you look at 2005, which I’ve called an unprecedented year, we treated just under 300,000 acres, and then you look at 2006 when we sprayed at least 415,000 acres, you can tell we’re having serious problems,” he said.
He said entomologists in Georgia and other states have reported similar outbreaks in recent seasons.
Spider mites traditionally have been considered a “cut out-type” pest in the Mid-South in that they appeared late in the season when growers finished making insecticide applications, Catchot said.
“In fact, they typically occurred so late that growers often were in a quandary as to whether they should treat or not,” he noted. “In Arkansas, Louisiana, Mississippi and other areas now, we’re seeing spider mites early, and, when I say early, I’m talking about one-leaf cotton.
“They seem to be even more devastating when they occur on small cotton. As I said, we’ve treated some acres for spider mites every year, but we weren’t seeing the damage we’ve seen in the last two years.”
Mid-South cotton entomologists believe the following factors may be involved in the increased pressure from spider mites:
-- Delayed burndown of no-till and minimum-till fields and lack of field border management.
-- Hot and dry conditions.
-- Beneficial insect reduction.
-- Increased use of insecticide seed treatments and fewer applications of Temik.
-- Development of resistance to some insecticides.
For those reasons, the entomologists are recommending several practices that could help growers treat fewer acres and not bust their budgets when it comes to insect control, according to Catchot:
First and foremost, he said, is “don’t create your own problems.”
By that Catchot and other entomologists recommend that, when possible, growers avoid early season applications that can flare mites by removing or reducing beneficial insects.
Second, growers should start clean; i.e., burn down their fields early and come back and re-treat “escapes” when needed.
Third, watch moving equipment from infested to non-infested fields.
And, finally, increase water volume and avoid low drift tips when making applications for spider mites to improve coverage.