By Bonnie Coblentz

MISSISSIPPI STATE -- The topic of many causal conversations this winter is no light matter to farmers who must make decisions for the upcoming year based in part on the weather.

January has not brought the freezing temperatures it usually does, and warmer weather means more crop pests can survive until spring. But a lack of cold weather did not stop the rain, which has brought area flooding to some portions of the state.

Dr. Charles Wax, professor of geosciences at Mississippi State University, said east central Mississippi averages 50 freeze days a year. As of the first week of February, the area had just 15.

"Through December, MSU had only nine freezes, while we typically average 13," Wax said. "We had just five freezes in January, instead of the average 16 for the month."

To farmers, this means more trouble with bugs. Dr. Blake Layton, extension entomologist at MSU, said temperatures to date have been kind to boll weevils, cotton's No. 1 pest.

"Boll weevils are susceptible to winter kill, but it takes a temperature of 10 degrees or lower at the site where the boll weevil is in diapause (hibernation)," Layton said. "Some boll weevils will die at higher temperatures, but to really have a significant impact on boll weevil populations, you have to get to that lower temperature."

A good winter kill of boll weevils is more important in 1998 than it has been in previous years, Layton said. About 340,000 acres of Mississippi cotton in the hills went into the boll weevil eradication program last fall. This greatly reducing the numbers going into diapause, but a heavy winter kill would have been a tremendous aid to the eradication effort.

"The Delta's 600,000 acres are not yet being eradicated, and a very heavy population of boll weevils went into overwintering there," Layton said. "Growers need to be concerned about these overwintered weevils this spring."

While temperatures have not killed bugs, rain has helped. Area flooding from the heavy winter rains has likely killed many boll weevils unhurt by the mild temperatures.

Boll weevils are not the only pest affected by winter weather. Stink bugs, traditionally a pest of vegetables, corn and especially soybeans, also are susceptible to winter kill.

"A mild winter opens the gate for higher stink bug populations," Layton said.

Tobacco budworms and bollworms are rarely affected by Mississippi's temperatures. The mercury usually does not drop low enough to hurt them as they overwinter as pupae an inch or deeper in the ground. Flooding, however, can affect the number that survive.

"The overwintering pupae just can't survive well in soils that experience prolonged flooding," Layton said. "In mid-winter, some can survive temporary flooding, but those that are beginning to break diapause in the spring are more likely to be affected."

River flooding has not yet been a problem in the state, but Wayland Hill, a civil engineering technician at the Army Corps of Engineers in Vicksburg, said strong El Nino years are wet years for the state.

"Generally, El Nino means a cooler-than-normal winter, not from cold temperatures but from cloudiness," Hill said. "It also means a lot of rain here and upriver in the Mississippi and Ohio river basins, which are big contributors to the Mississippi River."

The Mississippi River was high in January, peaking in Vicksburg at 37.4 feet on Jan. 23 and 46.1 feet in Natchez on Jan. 23 and 24. Flood stage at Vicksburg is 43 feet and 48 feet at Natchez. Some farmland and a few houses were flooded, but river water has not been a serious problem yet this year.

Hill said the Mississippi River is falling quickly now, but in 1983, the last strong El Nino year, the river had a high January, dropped to normal levels in February, then shot back up in March and April.