By
Linda Breazeale MISSISSIPPI
STATE Most of Mississippi's weather in 2000 did more harm
than good for the state's farmers -- until
December. After
four relatively mild winters, entomologists predict
significant insect mortality from the cold. The state
climatologist reported December temperatures were among the
coldest in reported history. "The
east-central Mississippi area posted the second coldest
average temperature for December since we started keeping
records in 1895," said Charles Wax, professor and head of
geosciences at Mississippi State University. "The average
temperature in 2000 was 36.1 degrees. The previous coldest
average had been 36.6 in 1963." Wax
said temperatures got as cold as 11 degrees and four days
did not get above freezing. "A
total of 24 days dropped to freezing or below in December,"
he said. "Rainfall was below normal at 2.42 inches, compared
to the normal average near 6 inches." Blake
Layton, Extension entomologist, said wet conditions combined
with the cold are more detrimental for insects than dry,
cold weather. Sudden drastic temperature drops and extended
extreme cold also are ideal for killing insects. "Boll
weevils have probably been the main victims of the cold
weather. At this point, we've probably had about 95 percent
mortality and because of the boll weevil eradication
program, we didn't have many weevils going into the winter
anyway," Layton said. "The
past four winters have been no help in the eradication
process, but this year should be a drastically different
story," he said. Layton
cited research that predicts 30 percent mortality in dry
conditions when temperatures reach 15 degrees for six hours,
85 percent when temperatures reach 10 degrees for six hours
and 100 percent mortality when it drops to 5 degrees for six
hours. "If
it's wet, there is significant mortality when it just
reaches 20 degrees for six hours," he said. Layton
said other insect pests knocked back by the cold include
stink bugs and fall armyworms. "Fall
armyworms never overwinter in Mississippi, but remain
relatively close in Texas and Florida during mild winters.
This year should push them even further away, and make it
take longer in the season for them to reach us," he
said. Evan
Nebeker, another MSU entomologist, has watched Ips and
southern pine beetle populations in recent years.
Mississippi pine trees had significant Ips damage in 2000,
largely because of drought-stress making trees more
susceptible. "Both
the Ips and the southern pine beetle populations should be
reduced from this winter's temperatures," Nebeker
said. The
southern pine beetle has been a major problem in Alabama,
prompting increased concern for Mississippi. "The
southern pine beetle is cyclic, and we are due for an
outbreak," Nebeker said. Released:
Jan. 15, 2001
Mississippi
Agricultural News:
2000 Weather
Finally Helps State's Farmers
Contact: Dr. Blake Layton, (662) 325-2085
Visit: DAFVM
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Last Modified: Friday, 17-Aug-07 14:25:37
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