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Cold Weather Chills Magnolia State Insects
By Douglas Wilcox
MISSISSIPPI STATE -- State farmers are hopeful that last winter's freezing weather helped give crop insect pests the cold shoulder for the 1996 growing season.
Mississippi State University entomologists are expressing "cautious optimism" on whether the low temperatures and prolonged wet winter had any effect on the insects that damage Mississippi crops each year.
Dr. Blake Layton, cotton entomology specialist at MSU, said Mississippi farmers may be in for a pleasant surprise this growing season because of the dipping mercury.
"I'm expecting less boll weevil damage to crops this year due to the six days of single digit temperatures the state experienced. The low temperatures not only killed many boll weevils but also the vegetation they survived on," Layton said. "We hope it will take at least four years for a generation to gain another foothold on a crop."
Farmers are hopeful that the winter weather affected one of Mississippi's more destructive pests, the tobacco budworm. Last year the budworm caused a 28 percent yield reduction of crops in some areas of Mississippi.
Budworm pupae already have been found in untilled fields in Monroe County. Layton said it's too early to tell whether the budworm was affected by the winter.
"We are finding some surviving pupae and it is a concern, but the information we've gathered is still being interpreted and doesn't translate to all fields," Layton said. "Many budworms are killed in the tilling process, and we usually don't have severe outbreaks two years in a row."
Predatory insects and disease also could push down large populations of budworms.
Dr. James Jarratt, extension entomologist at MSU, said insect survival depends largely on the site they chose for overwintering.
"Budworms overwinter as a pupae and are encased and somewhat protected but unable to move around. Chinch bugs and boll weevils move around during the winter and can make adjustments depending on vegetation or temperature," Jarratt said. "The up-and-down temperatures in late January also might have affected the insect population, but it's too early to tell."
Another cold winter benefit Mississippi farmers could look forward to is a decrease in insecticide use this season.
"We're always concerned when we have a large insect population such as the budworm which may become spray resistant," Layton said. "After a cold snap, if the population has decreased, we spray less. This allows the beneficial insects to survive."
Dr. Charles Wax, head of the MSU geosciences department, said Mississippi is not the only state experiencing a "winter with no end." Much of the eastern United States has experienced colder temperatures than normal for this time of year.
Wax said farmers can't rely on the winter temperatures staying low year after year.
"It has been colder the last few years, but it's not a trend. This winter was different because it was continuously cold and stayed that way. We also had both record high and record low temperatures in February," Wax said.
On the average, Mississippi has about 52 freezes a year. From Nov. 4, 1995, through March 31, 1996, the state had 78 freeze days with seven straight days of freezing temperatures occurring Nov. 11 through 17.