War On Insects

A Healthy Start On Cotton Production Can Keep You A Step Ahead On Insect Control

LONOKE, ARK.
   Cotton insect control and how that affects the bottom line in cotton production was presented by Dr. Gus Lorenz, extension entomologist from the University of Arkansas Division of Agriculture, recently.
   “Starting at the beginning of the season one of the things that has been a problem for us in Arkansas the last couple of years and in the midsouth too is thrips control,” he said. “We’re in a situation now with thrips where we’re putting seed treatment out and coming back with two or three foliar applications, and we don’t feel that’s sustainable for our cotton growers. It’s just an untenable situation in regards to profitability. We can’t afford to spend $25 to $30 an acre just controlling thrips.”
   So Lorenz is urging farmers to get the best growth possible by starting that cotton out in the right way and keeping it as pest free as possible. With the current situation with cotton prices, it’s imperative that everything is done to keep the health of the plant up while still maintaining profitability.
   “We’re concerned about the situation and I think a lot of it revolves around the fact that we’re having to deal with resistant pigweeds; that’s resulted in a lot of preemerge herbicides and then post emerge herbicides and those are having an impact on the growth of the cotton,” Lorenz said. “We know that anything that slows the growth of that cotton at that particular time is not conducive to good pest management. That’s when thrips, diseases and nematodes all jump on that cotton if it’s not growing and being healthy, so we’re concerned about finding some ways to control thrips without spending that much money on thrips control.”
   Lorenz also discussed plant bugs, which have become the number one pest of the midsouth.
   “We’re trying to find ways to control plant bugs as economically as possible and maintain the level of plant bug control that we need,” he said. “We have growers in the south part of the state and also in Louisiana and Mississippi that are spraying 10 and 12 times a year to control plant bugs, so we have to find some ways to improve our plant bug control. We can improve our efficiency and our control by tank mixing pesticides and shortening the time interval. When plant bugs are really bad you can’t wait seven days to make another application. You may need to treat at a shorter interval like four or five days after one application. You may have to come back again to get the population under control. So tank mixing and shortening the time interval between treatments when those plant bugs get bad are two things that we can do to reduce the number of applications that we’re making for plant bugs.”
   Studies show that if you only spray plant bugs once a week when plant bugs are really bad, it’s almost as bad as if you didn’t spray at all. So farmers must get out of the mindset that they can only get across that field once a week. Sometimes when numbers are really bad it takes a couple of applications in short intervals to really break their back and get the population under control.
   “There’s a new product out there now called Transform that’s a new class of chemistry, and our studies show that in most cases the level of control meets or exceeds the current standards,” Lorenz said. “We often times see yield advantage, yield increase with applications of Transform because the level of control is so good. So it’s important that we use the right products at the right times and we learn how to use those products in sequential applications to achieve the level of plant bug control that we want.”
   Since 95 plus percent of cotton now is dual gene, there’s beginning to be a little slippage with bollworms getting through the dual gene technology. Widestrike or Bollgard II are not fully containing these pests.
   “We’re looking at foliar applications of insecticides to supplement that control that we get with the dual gene cotton,” he said. “We’ve been looking at several products like Belt and Prevathon. We found that, in a lot of cases where numbers are particularly bad on bollworms, well-timed applications of Prevathon in particular can increase yields on dual gene cotton. This happens particularly in Widestrike in a lot of our trials, because we’ve known it doesn’t quite control bollworms as well as Bollgard II; but certainly even in Bollgard II at times when populations are really bad we can increase yields with foliar applications on dual gene cotton.” Δ
   BETTY VALLE GEGG-NAEGER: Senior Staff Writer, MidAmerica Farmer Grower 

Dr. Gus Lorenz, extension entomologist from the University of Arkansas Division of Agriculture, explains cotton insect control and its affect on the bottom line. Photo by John LaRose Jr.