What is in this article?:
- 'Incredible' new diamide chemistry needs stewardship to avoid resistance
- Coverage is important
- Early planting soybean system
The diamide class of insecticides is "probably the most incredible chemistry my colleagues and I have ever seen on caterpillar pests," says Angus Catchot, Mississippi State University Extension professor of entomology. "It's very selective, but very, very efficacious."
AMONG THOSE attending the annual meeting of the Mississippi Agricultural Consultants Association were, from left, Allen McKnight, Delta Agri-Consulting, Greenville, Miss.; Jack Clayton, FMC, Tunica, Miss.; Gill Corban, Jimmy Sanders, Inc., Cleveland, Miss.; and Jay Turner, Brandt Co., Southaven, Miss.
Early planting soybean system
A “big project” on early-planted soybeans in the hills and Delta is continuing, Catchot says, and generating massive amounts of data.
“Eleven years ago, when I started work at Mississippi State University, about 65 percent to 70 percent of our beans were Group IVs that were planted before May 1st — and we weren’t spraying a lot of loopers.
“Now that cotton acreage has declined sharply, and we have a lot more corn and we’re planting a lot more beans behind wheat, we’re planting a lot more soybeans late. And we’re seeing a lot more caterpillar problems.
“I still contend that the early planting soybean system developed by Dr. Larry Heatherly is the best soybean pest management program we have. Those soybeans have always been the least affected by pests.”
The soybean project includes Group IV and Group V varieties with seven planting dates, starting in March and going into July in both the hills and the Delta, Catchot says.
“On top of those planting dates, we have four treatments: (1) Prevathon only, to try and simulate what the value of a Bt soybean might be for Mississippi producers; this includes automatic 14 oz. applications of Prevathon alone every couple of weeks; (2) a threshold level treatment, (3) an untreated check, and (4) a disruptive treatment — an automatic insecticide application at R-3.”
The Prevathon/Bt simulation came out on top, threshold was second, untreated was third, and automatic disruptive spray came in last.
“The point of this,” Catchot says, “is that if you don’t have bugs in the field, you can make a problem that can actually hurt you, that will penalize you on yield, by spraying when pests are not there. “
A graduate student, Brian Adams, has been doing work to reevaluate insect thresholds in soybeans, he says.
Findings are still preliminary, “but one of the things the data are suggesting is that there’s a lot more compensation for corn earworm damage in soybean plants than we previously thought. We’ve seen as much as 50 percent damage to plants in early growth stages, with very little yield loss.
“This is ongoing, but we working hard to reevaluate all our thresholds in soybeans under today’s management systems.”