A farmer who typically doesn't do a lot of scouting for insects unless he sees an obvious problem in the field sighed and noted, "Well, I guess I better start looking for black cutworm- everybody is making such a big deal about it."
If he follows through and scouts, Dave Nanda, a crops consultant and director of agronomics and technology for Seed Consultants, Inc., thinks he will have made a wise choice. 'Everyone is talking about it' because the threat is real, Nanda notes. The perfect storm may have set itself up for black cutworm this year. Moth counts in traps by entomologists and people who report data to entomologists indicate near historic catches in both Illinois and Indiana.
There are some important points to keep in mind about black cutworms, Nanda observes. First, it takes 40-50 days form when eggs hatch to when they become adults. Their development depends upon temperature and moisture. Warm weather in the early days of May probably favored their development.
Second, black cutworms really don't like feeding on corn or soybeans. However, when weeds are destroyed and they're hungry, small larvae feed on corn leaves, Nanda notes. Small, irregular holes in young corn leaves can be an early tip-off that you ought to be looking for black cutworms.
Third, the insects feed above ground until the larvae are about a half inch long. In insect terminology, it takes three instars to get to that stage. Each instar stage requires 100 to 140 growing degree says.
The real threat starts at about the fourth instar stage, Nanda notes. The insects are ready to do real damage, and at this stage may cut plants above or below ground.
Finally, realize that they may not be the easiest pest to find when you go scouting for the,. They hide during the day and feed at night. Scout your fields once per week