Over the last few weeks, caterpillars have arrived in large numbers to some Georgia peanut fields, and moisture-stressed fields need to be checked for lesser cornstalk borer.

In an Aug. 9 blog post, Dr. Mark Abney, University of Georgia peanut entomologist, says “If you were waiting for the opportune moment to scout your peanuts, this is it.”

He says the Velvetbean caterpillars have arrived, and peanuts 70 to 90 days after planting are likely at the greatest risk for yield loss due to defoliation. Risk is even greater for drought-stressed fields. The VBC can completely defoliate peanuts if left unchecked, but it has been easy to kill in recent years.

“A pyrethroid would be my choice for VBC in irrigated fields. I recommend growers choose a caterpillar specific product in non-irrigated fields. The selective, caterpillar-specific insecticides will be more expensive up front, but they generally provide better residual activity and result in a much lower risk of secondary pest infestation. This is important with the hot, dry weather we are seeing in many areas, and I expect spider mite infestations will become more plentiful in the coming weeks,” he says.

Some locations have experienced drought stress, and these fields particularly need to be checked for lesser cornstalk borer infestation. “Allowing LCB populations to continue to grow will result in lost yield and significantly increase the risk of Aspergillus flavus,” he says.