Purdue News
Purdue NewsMarch 6, 1998
According to Richard Latin, a Purdue University Cooperative Extension Service plant pathologist, Midwestern sweet corn will be threatened by Stewart's Wilt. The disease causes wilting and collapse of young leaves of the corn plant around April or May, and results in reduced yields and low-quality ears.
"The warmer the weather, the more severe the disease will be. It looks as though there's a fairly severe Stewart's Wilt threat for 1998," Latin said.
The spread of this disease depends on the survival of corn flea beetles, which act as a carrier, Latin said.
"The pathogen is a bacterium that survives in corn flea beetles. If the weather is very cold, then very few beetles will survive," he said. "With the mild winter this year, there will be more beetles with the potential of harming the corn plants."
Farmers can prepare for Stewart's Wilt before planting season begins, Latin said.
"There are numerous sweetcorn varieties that have resistance to Stewart's Wilt. You can select varieties for a year like this. Farmers still have time to select the appropriate variety and avoid serious losses due to disease," he said.
Latin also noted that the mild weather may reduce the chance of some other diseases by helping soil microorganisms decompose disease-harboring crop residue.
Rick Foster, Purdue Extension entomologist, said he expects to see more corn flea beetles among young crops. The beetles feed on the leaves of the young corn plants, removing green tissue and giving the leaves a frosted look.
"When the corn comes up, growers should be on the lookout for the flea beetles," he said. "There's usually enough that survive to cause problems if conditions are right during the spring or summer."
For most insects, though, winter weather doesn't matter. Foster said that insects have such a high reproductive rate that given favorable conditions in the spring and summer, populations could explode.
If the El Nino brings a hot summer, farmers can expect increased numbers of European corn borers, a caterpillar pest that feeds on the leaves and the kernels and bores into the corn stalk.
"With adequate moisture, that's one insect we know will do well in a hot year," Foster said.
CONTACTS: Latin (765) 494-4639; e-mail, latin@btny.purdue.edu, and Foster (765) 494-9572; e-mail, rick_foster@entm.purdue.edu
Compiled by Chris Sigurdson, (765) 494-8415; E-mail, sig@ecn.purdue.edu
Purdue News Service: (765) 494-2096; e-mail, purduenews@purdue.edu
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