Protect Your Crop From LCB Scout plants, pegs and pods for this yield-robbing insect. By Amanda Huber Silken tubes on pegs are a sign of LCB.
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t’s the No. 1 most destructive insect pest of peanuts in the Southeast, says Mark Abney, University of Georgia Extension entomologist. Lesser cornstalk borers thrive in hot, dry conditions, a weather pattern usually found at least some point during most peanut-growing seasons. Scout For Trouble LCB’s prime activity period generally begins in June and continues through the summer months. Larvae feed above and below the soil line and can kill newly emerged seedlings, destroy pegs and developing pods, damage plant crowns and weaken plants that survive. Wilting is one of the earliest signs of LCB infestation. Withered buds, stunting and plant deformities are also common. “You will usually see lessers in the driest spots in the field first,” Abney says. “Look for plants that are wilted and/or have skips beside them and plants at the ends of rows. Checking these areas first can save a lot of scouting time. If the larvae are not here, they are not likely to be in other parts of the field.” The presence of moths may be the first sign LCB is in the field. A single moth will lay from 100 to 200 eggs near the soil surface. After hatching, larvae live in the soil and construct tunnels from soil and bodily fluids tightly woven together with silk. These silken tubes are often found more than the insect itself. Larvae leave the tubes to feed at the base of the plant. “Look for wilted stems and silk tubes, remove plants and check tap root, pods and stems for feeding injury and larvae,” Abney says. “They are not always easy to find.” 10 /
THE PEANUT GROWER • JUNE 2020
Weather Plays A Role Producers may want to take a waitand-see approach early in the season when LCB populations are low, but as pegs and pods are developing, that is the time to protect the crop from feeding. “Scout and spray when the pest is present. If LCB populations get out of control in a field, it will be difficult to reign them back in. If you do not have
LCB in your fields, there is no reason to apply a preventative insecticide.” During those times when hot, dry conditions prevail, LCB pressure could be greater. “Rainfall will help slow population growth, and we do not usually see LCB problems under pivots when adequate water is being applied. It is important to scout young peanuts under pivots as PEANUTGROWER.COM
