Good news for corn farmers: a major corn crop pest, the
European corn borer (ECB) has seen a significant population decline in the
eastern United States. This information comes from Penn State researchers on
the heels of reports of similar population declines in the Midwest. As a
result, farmers will save millions of dollars in some parts of the country
because they will no longer need to treat for this pest.
ADVERTISEMENT
“ECB, which was introduced to North America from Europe
in the 1900s, used to be the most important pest of corn in the United
States,” said John Tooker,
assistant professor of entomology. “Not that
long ago, it caused crop losses that annually approached $1 billion nationwide,
and $35 million in the northeastern United States.”
According to Tooker, to protect their crops from ECB, many
farmers have grown a genetically modified type of corn that expresses insecticidal
toxins that kill the worms. These toxins were isolated from the bacterium
Bacillus thuringiensis (Bt).
“These Bt corn hybrids have been widely adopted because
they are exceptional for managing ECB — 99.9 percent of larvae are expected to
die when they feed on plants expressing Bt toxins,” he said. “Yet a
drawback to using these hybrids has been the high cost of purchasing the seeds,
which can decrease potential profits.”
To understand current ECB populations in Pennsylvania field
corn, the researchers assessed larval damage in Bt and non-Bt corn hybrids at
29 sites over three years. Specifically, they planted Bt and non-Bt corn
hybrids on farm sites across four growing zones in Pennsylvania in 2010, 2011
and 2012. During September of each season, they assessed corn borer damage on
400 random plants at each site. They sliced open stalks, and recorded the
number of ECB tunnels and larvae per stalk. They also evaluated corn ears for
ECB damage.
“Our results confirm that we are seeing widespread
population declines of ECB in the East, similar to declines that have been
found in the Midwestern United States,” said Eric Bohnenblust, graduate
student in entomology. “With less ECB damage around, non-Bt hybrids in our
tests yielded just as well as Bt hybrids, so the decline in ECB populations
provides an opportunity for growers to generate greater profits by planting
high-yielding non-Bt seed, which is much cheaper than Bt seed. Secondarily,
planting more non-Bt corn will reduce the potential for ECB to develop resistance
to Bt toxins as corn rootworms have done in about a dozen states so far.”
Read more at Penn
State.
ECB
corn feast via Shutterstock.