Scientists have suspected higher mycotoxin levels may follow
increased insect damage, but ARS entomologist
F. Dowd found fumonisin levels 30- to 40-fold lower in Bt corn than in
non-Bt varieties in Illinois cornfields. Bt stands for the biopesticide
Environmental conditions and the specific Bt corn hybrid play
roles in the actual amount of reduction seen, but corn varieties that expressed
the Bt protein throughout the plant rather than in specific areas were the
least likely to have significant fumonisin levels, according to Dowd, who is
with ARS National Center for
Agricultural Utilization Research in Peoria, Ill. ARS is the
U.S. Department of Agricultures chief
in-house research agency.
While Bt corn is modified mainly to resist European corn borers,
Bt corn also showed lower levels of mycotoxins when corn earworms were present
in fields, although not as significant a reduction as when European corn borers
were the primary insect pest.
This may encourage the creation of corn varieties with more
resistance to a variety of insects in order to provide more protection from
Small plot studies by Iowa State
University plant pathologist
Munkvold appear to confirm Dowds findings.
Scientific contact: Patrick Dowd, ARS
National Center for Agricultural
Utilization Research, Peoria, Ill., phone (309) 681-6242, fax (309)