Retention of Pantoea agglomerans Sc1R across stadia of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae)

Southern green stink bug [Nezara viridula (L.)] adults and other pentatomid pests can transmit pathogens (e.g., the bacterium Pantoea agglomerans) that cause disease in cotton (Gossypium hirsutum L.) and other high-value cash crops worldwide. First instars of N. viridula were recently shown to ingest P. agglomerans strain Sc1R with rifampicin-resistance, and to retain the pathogen to the 2(nd) instar. The objective of this study was to determine the acquisition of P. agglomerans Sc1R by early instars of N. viridula and determine persistence of P. agglomerans Sc1R across subsequent stadia. In three trials, early instars (1(st) and 2(nd)) were exposed to P. agglomerans Sc1R and subsequently maintained to adulthood; cohorts were sampled at 3(rd) and 5(th) instars, as well as adults. In every trial, P. agglomerans Sc1R was detected in all stadia, including adults, but significantly higher frequencies of infection than expected were observed at the initial stage of infection (either 1(st) or 2(nd) instar). Higher densities of P. agglomerans Sc1R were detected in 1(st) and 2(nd) instars, and lower densities were observed in subsequent stadia. Densities of innate microbiota were generally lower when the initial stage of exposure was at 1(st) instar than when the initial stage of exposure was at the 2(nd) instar. Overall, half of the adults possessed P. agglomerans Sc1R. These findings demonstrated that N. viridula nymphs can acquire P. agglomerans Sc1R and retain the pathogen to adulthood. Potential avenues of research to further elucidate the implications of nymphs harboring pathogens to adulthood are discussed.