Don’t Let Dollar Cotton Drive Insect Thresholds
February 13, 2012 With cotton prices nearly double what they were at this time last year, will growers be motivated to lower insect thresholds and pull the trigger earlier than normal on insecticide sprays, particularly for plant bugs? Will they keep firing away later into the season? Seems logical that they would, right?
“You know, it’s all about the bottom line. What history tells us with cotton insects is that insecticide money is better spent from mid-season on, rather than early in the season,” says Dr. Gus Lorenz, an Arkansas Extension Entomologist and IPM Coordinator in Lonoke. “We also realize growers don’t plant cotton to have something to spray, they are growing cotton to make a living.”
By holding off of plant bug sprays until established economic thresholds are met, flaring of aphids and spider mites is less likely to occur. “That’s why we have the thresholds for plant bugs – to help us use our products when the grower is best served, to prevent economic loss, and avoid applications that aren’t needed,” explains Lorenz. “The bottom line in my opinion is that just by eliminating all pests early season doesn’t necessarily equal greater yields in the end, and definitely doesn’t always mean higher profits.”
Plant bugs are now the number-one cotton insect pest across the Mid-South and parts of the Southeast. That’s been established. What had not been established, as the plant-bug was becoming such a yield-robbing pest, was when to treat.
“The entomologists in the Mid-South are a tight group and work very well together. The first time we got together, we couldn’t all agree on anything – like what the threshold was, or the correct technique for sampling,” Lorenz explains. “We decided that if we couldn’t agree on anything, how can our consultants and growers know when to do it, and how to do it?
“So we started working on a project for, first, deciding what the best sampling methods were. Once we got that done, we started working on our thresholds. We all worked together and the data is very good. We feel very comfortable with those recommendations as they stand today,” says Lorenz.
So, to make your insecticide applications less expensive and more effective, use established thresholds, and work with your entomologist and state Extension Service.
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