By Jamie Martin
Corn earworm remains a leading insect threat in soybean production and can significantly affect profitability through crop damage and pest management costs according to Dominic Reisig, Professor and Extension Specialist, Entomology & Plant Pathology at North Carolina State.
The pest typically becomes more noticeable later in the season. Many populations develop in corn before adult moths move into soybean fields during flowering. Some moths may also migrate from southern areas, creating earlier-than-expected infestations.
This year, higher numbers have been reported in some early-planted soybean fields. As a result, many growers are questioning whether insecticide applications are needed during the beginning of flower and full flower growth stages.
Research indicates that soybean plants can tolerate substantial flower feeding during the R1 and R2 stages. Because soybean plants naturally produce more flowers than needed, they often compensate for damage without suffering to yield losses.
Field conditions remain an important consideration. When plants experience drought or other forms of stress, their ability to compensate may decline, increasing the potential impact of feeding damage.
Attention should increase once soybeans reach the beginning of the pod stage. Pod feeding carries greater risk because developing pods contribute directly to yield. Fortunately, soybeans still possess a strong ability to recover when growing conditions are favorable.
Studies involving both full-season and double-crop soybeans found that determinate and indeterminate varieties could compensate for corn earworm injury. Healthy plants generally recovered well after feeding events.
Growers should continue scouting fields and tracking moth flights using available monitoring networks. Regular observations help identify periods of increased risk and support informed treatment decisions.
When control is needed, effective options include Blackhawk, Denim, Intrepid Edge, Steward, and Vertento. Experts recommend limiting the use of broad-spectrum insecticides unless another pest requires treatment.
These products can reduce beneficial insect populations and increase the likelihood of secondary pest outbreaks, including soybean loopers and spider mites.
Photo Credit: istock-sandramatic
Categories: National