Soybeans were scouted at the V4 growth stage and areas of dark brown discoloration on the stem were observed. When scouted, groupings of immature and adult kudzu bugs were observed. The damage detected in this field was minimal. Damage observed was consistent across the field.
Conclusion
This injury was confirmed by a NC State Extension Specialist as damage from Kudzu Bugs. Kudzu bugs tap through the veins of plants to reach the phloem, using piercing sucking mouthparts. Which is why symptomology may look like stem discoloration, or lead to sooty mold on the leaves. Economic threshold for spraying kudzu bugs is five bugs per plant until mid-July, when we switch to a sweep net-based threshold. It is recommended that if an insecticide is needed, it is applied once the migration period is over.