By Linda
Breazeale MISSISSIPPI
STATE -- As if the drought wasn't hard enough on this year's
corn crop, growers now prepare for harvest with the threat
of yield-reducing corn borers and a drought-related
fungus. Dr.
Scott D. Stewart, assistant Extension entomology specialist
in Raymond, said most of Mississippi's crop has damage from
corn borers, especially in the Delta counties. "Last
year's mild winter and the increasing corn acreage probably
combined for a larger-than-normal first generation of corn
borers. The second generation usually causes the most
damage," Stewart said. "Many fields were treated at least
once, but there will not be any need to treat this third
generation because of the crop's growth stage." Dry
conditions in early summer reduced much of the state's corn
potential, but corn borers are the biggest yield reducers in
irrigated fields. As their name implies, these pests bore
into the stalk and where the ear attaches, impeding
nutrition and weakening the plant. "A bad
storm will increase the damage caused by the corn borers by
knocking over the weakened stalks," Stewart said. An
additional threat lurking around Mississippi's dry land corn
is aflatoxin, a fungus that may grow on corn
kernels. Dr.
Erick Larson, Extension corn specialist at Mississippi State
University, said aflatoxin tends to increase during
excessively hot, dry summers. It is usually a bigger problem
at the beginning of harvest because fields that were most
stressed mature first. Grain elevators reduce prices for
infected corn or reject whole truckloads if the
contamination is extreme. "Producers
can minimize the threat of aflatoxin buildup in the field by
harvesting early. Harvesting early reduces fungal exposure
to warm, humid conditions during dry down by artificially
drying the corn," Larson said. "Wet grain that is not dried
quickly during warm conditions will begin heating up to
intolerable levels rapidly. Therefore, dry any wet grain to
below 15 percent moisture within 24 hours or haul to an
elevator immediately." Larson
said growers should not store wet grain in trucks, combines,
bins or any non-aerated site more than four to six hours
before beginning drying. Don
Smith, agricultural Extension agent in Adams County, said
aflatoxin reports from Louisiana have him concerned, but it
is too early for Mississippi growers to report
problems. Corn is
typically accepted if it has up to 20 parts per billion of
aflatoxin. In Louisiana, reports have ranged from 300 to
1,400 parts per billion. Corn at that level of contamination
cannot be fed to poultry or livestock. Young animals are
more sensitive to aflatoxins, and poultry and swine are more
sensitive than cattle and sheep. Lactating dairy animals are
a special concern because low levels of aflatoxins in the
feed can result in unacceptable levels passing into the
milk. Contact:
Dr. Scott Stewart, (601) 857-2284
Mississippi
Crop Report:
Corn Growers
Prepare For Challenging Harvest
-30-
Released: July 31, 1998
Visit: DAFVM
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Last Modified: Friday, 17-Aug-07 14:29:27
URL: http://msucares.com/news/print/cropreport/crop98/980731cr.htm
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