It’s that time of year again; the time producers and consultants do battle with one of the most economically damaging pests – the lesser cornstalk borer (LCB). The LCB’s prime activity period generally begins in June and continues through the summer months. A dry-weather pest, the lesser cornstalk borer favors crops grown in the sandy soils common in southern states from North Carolina to Texas.
Lesser cornstalk borer 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.
Early Warning For Early Plantings
Producers, especially those who planted earlier this year, are reminded to watch for an early onset of insects favoring the dry weather, says Ayanava Majumdar, Auburn University Extension entomologist.
“Many insect pests, like earworms and armyworms, favor stressed plants, and you may see caterpillars earlier than usual,” he says.
Majumdar says producers with irrigation may not be as worried, but irrigation or not, scouting is the best strategy to monitor insect populations that often start from the field borders. “Soil insect pests, like the lesser corn stalk borers, may get really bad later in the season, if the drought persists.”
Because of the critical importance of correct identification of insect pests, he recommends contacting your Extension agent for assistance with identification and for the latest recommendations.
Protection Between Sprays
Field scouting, along with proper timing of treatment applications, is key to managing LCB. Retired Colquitt County Extension coordinator Scott Brown says worms can also build up between spray intervals requiring producers to make a separate trip through the field to spray for foliage feeders. He says producers who use a Dimilin program do not usually have to make interim sprays because the insect growth regulator provides enough control of foliage feeders to prevent them from reaching threshold levels.
“When we piggyback Dimilin with our peanut fungicide sprays, we often end up not having to use the more expensive pesticides for worm control and may also eliminate the need for an additional trip across the field, which saves money on labor and equipment,” he says.
Get In The Field
Dimilin is an insect growth regulator that interferes with chitin deposition and produces a weak or malformed insect exoskeleton. After ingestion, immature larvae are unable to molt to the next developmental stage, stopping them before they have a chance to damage plants.
Scouting for both soil insects and foliage feeders and knowing what to look for given the weather pattern is the best way to find insect pests and prevent these pests from reaching a potentially devastating level. PG
Portions of this article were provided by Chemtura AgroSolutions