Boll Injury Caused By Leaffooted Bug in Late-Season Cotton

Leaffooted bug, Leptoglossus phyllopus (L.) (Hemiptera: Coreidae), has been observed in large numbers on cotton late season in south Texas and elsewhere in U.S., but reports of economic damage to cotton are sporadic. As an initial look at cotton-leaffooted bug interactions, field-collected leaffooted bugs were caged on cotton to characterize boll injury and examine within-plant distribution of boll injury within the context of its late-season occurrence. Boll injury type and symptomology of cotton boll rot observed on leaffooted bug-infested bolls were similar to that previously documented for stink bugs. There was more boll injury to the relatively younger bolls in the middle branch section of the plant (1.28 boll injury average based on a 0 to 4 injury scale) than on bolls in lower branches, which was most obvious at the one leaffooted bug per plant infestation rate  Cotton boll rot generally followed the same pattern: higher frequency of boll rot symptoms on bolls in the middle branches (average of 30%). The next year under more severe water-stress conditions, the amount of boll injury and cotton boll rot was marginally lower, and about the same in middle and lower branches. Despite boll injury and rot at levels known to affect yield, there were no yield differences detected in the late-season cotton caged in these experiments. Overall, leaffooted bug injured bolls, and data supported it as a suspect vector of cotton boll rot. Yet, yield loss was not detected using late season cotton that coincided when leaffooted bug has been observed in commercial fields. We propose that risk of yield impact is low when leaffooted bug movement into cotton is first detected late season. Should leaffooted bug occur earlier in cotton development, risk to yield likely increases, and further study would help evaluated the risk across boll age and cotton development.