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“It would take 90 hours of scouting for southwestern corn borer egg masses to get the same precision you can get with just four pheromone traps," says Fred Musser, associate professor of entomology and plant pathology at Mississippi State University. "I don’t know of anyone who wants to spend 90 hours on making a single decision.”
BEN MERIWETHER, left, Valent USA, Tupelo, Miss., and Rhett Ruscoe, BASF Corp., were among those attending the annual conference of the Mississippi Agricultural Consultants Association.
If you grow non-Bt corn and you’ve spent a lot of sweaty time in fields scouting for southwestern corn borer egg masses and larvae, Fred Musser has relief for you.
Pheromone traps are just as effective, take less time, and are cheap, he says.
“The big problem with scouting for egg masses/larvae is that it’s incredibly time-consuming,” he said at the annual meeting of the Mississippi Agricultural Consultants Association at Mississippi State University. “You’re out there in 15-feet tall corn, early silk stage, miserable heat and humid conditions, trying to sort through massive amounts of leaf tissue, searching for an extremely small egg mass that’s very easy to overlook.”
Because of this, says Musser, associate professor of entomology and plant pathology at MSU, many growers and consultants are less than enthusiastic about scouting for the pest, and even those well-trained in the procedure will often obtain insufficient information on which to base a treatment decision.
In a study from 2007-2010, with support from the Mississippi Corn Promotion Board, five traps were placed around commercial non-Bt corn fields and checked weekly. At the same time, physical inspections of corn plants were done weekly to look for eggs and larvae. As harvest neared, stalks were split to determine how much tunneling had occurred.
“These pheromone traps are very specific — they catch very few insects other than southwestern corn borer,” Musser says. “And you can place them where they’re easily accessible.”
Results showed that pheromone traps and egg sampling “were about equal in how we were able to predict the amount of tunneling — there wasn’t much difference in their accuracy. The big difference was in the amount of effort required.
“What the data tell me is that, with the egg scouting method, we were missing many of the egg masses. And this was by people we’d trained and who knew what to look for.”