This year's rapid pace to corn planting and vigorous emergence may give corn plants an important head start against insects, a University of Illinois entomologist reports.
For example, Mike Gray says that despite intense flights of black cutworm moths this past week across many areas of Illinois, he believes the prospects for widespread black cutworm problems this spring are low.
"In general, early tillage or early planting of corn work against the establishment of economic infestations of black cutworms," Gray says. "Removing weeds from fields this spring at such a good pace significantly reduced the chances for black cutworm survival."
In general, no-tillers in areas susceptible to black cutworm have been urged to burn down their fields to remove weeds, which serve as a place for moth to lay eggs. Gray says black cutworm moths will still lay eggs on crop residue, and soybean residue is preferred to that of corn.
"So first-year corn remains at greater risk to black cutworm injury than continuous corn," he says.
Gray says many other insects overwinter each year throughout much of the Midwest, including European corn borers, corn flea beetles, grape colaspis, western corn rootworms, white grubs and wireworms.
"In general, the early planting and establishment of corn root systems will enhance the survival of root feeders, such as the grape colaspis, western corn rootworms, white grubs and wireworms," Gray says. "However, good growing conditions and warm soil temperatures should allow corn seedlings to grow more rapidly through susceptible seedling stages of development."
Gray says cool, wet springs may slow corn seedling development sufficiently to enable insects such as wireworms and corn flea beetles to feed longer, causing more injury.
He says western corn rootworm densities have been lower the last 2 years in Illinois.
"It will be interesting to see if the early planting results in larger densities of this perennial insect pest this season. I suspect this may happen," Gray says. "With regard to the European corn borer, early planting favors the establishment of the first generation. With the historically low overwintering population, this insect is still unlikely to cause much notice this year across Illinois."