What is in this article?:
- Pheromone traps: an easier way to scout for corn borers
- Savings of time, effort
- Changes in control recommendations
“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.
Changes in control recommendations
Other changes in insect control recommendations include:
• Soybeans: Recommended termination of insecticides for defoliating insects has been changed from R7 to R6.5. “Data we collected on defoliation in 2009-10 show less yield loss during R6,” Musser says. “By terminating at R6.5, you won’t have reached economic injury level before beans reach R7 stage.
• Bean leaf beetles: “The old threshold was 20% defoliation during reproductive stages or 2 insects per sweep and we were triggering a lot of unnecessary sprays. We’ve changed it to 20 percent defoliation or 50% plants with pod feeding and eliminated the 2 insect/sweep threshold.”
• Stink bugs: Damage at R3 and R4 can cause “pretty big yield losses from relatively low densities of stink bugs,” Musser says, “but at R6-R7, the only loss is quality. In most years in most situations, they don’t do enough quality damage to cause economic loss. So, we’ve have changed our late season R6 threshold to 20 stink bugs per 25 sweeps.”
• Three-cornered alfalfa hopper: “Our threshold is 2 insects per sweep during reproductive stage. Later in the season, it’s still 2 per sweep, but our ongoing research suggests it could be much higher than 2. In cage studies by a graduate student,” Musser says, “we were getting girdling, but we’ve not been able to document yield loss, even as high as 8 adult insects per sweep.
“Termination has been moved back to R6 instead of R7, because they’re just not doing that much damage at that point.”
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