Transmission of Eremothecium coryli (syn. Nematospora coryli) to Consecutive Cotton Bolls by Individual Stink Bugs1

Abstract

Cotton (Gossypium hirsutum L.) is a high-value cash crop persistently plagued by insect pests such as stink bugs and related species. Stink bugs vector pathogens that cause necrosis of cotton seed and lint, yet the frequency of pathogen transmission into successive bolls by individual stink bugs is not documented. Individual adults of southern green stink bug, Nezara viridula (L.), (n = 80) were provided green beans (Phaseolus vulgaris L.) infected with the fungus Eremothecium coryli (Peglion) Kurtzman (syn. Nematospora coryli Peglion) and caged sequentially with five bolls of known age to determine potential for infection of consecutive bolls by a single stink bug. Stink bug adults fed on 82.4% of bolls (n = 108), and the pathogen was transmitted to 68.5% of these bolls (n = 89). As expected, insect bacterial flora was detected in all bolls with evidence of insect feeding. Overall, frequency of feeding ranged from one to five bolls per stink bug; frequency of boll infection also ranged from one to five bolls per stink bug. The frequency of infection by E. coryli in bolls did not differ between sexes of stink bugs (Fisher's Exact Test: P = 0.84), and the number of females and males infecting one to five bolls did not differ (Fisher's Exact Test: P = 0.92). The findings can serve as an impetus for determining whether current insect management thresholds should be reconsidered given the potential for infection of multiple bolls by individual southern green stink bugs.