Pathogen transmission in cotton by the southern green stink bug

Authors: Esquivel, Jesus; Medrano, Enrique

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/21/2009
Publication Date: 7/23/2009
Citation: Esquivel, J.F., Medrano, E.G. 2009. Pathogen transmission in cotton by the southern green stink bug. Proceedings of the Mexican Phytopathological Society. CDROM.

Interpretive Summary: Stink bugs have become pests in U.S. cotton, and their presence has coincided with cotton disease. This study was conducted to assess whether southern green stink bugs could transmit disease pathogens to cotton bolls. Ingestion of four pathogens (Pantoea agglomerans, P. annanitis, Klebsiella pneumonia and Nematospora sp.) were assessed after southern green stink bugs fed on green beans containing each respective pathogen. Laboratory processing indicated all pathogens were ingested but greenhouse trials showed that only P. agglomerans and Nematospora sp. were transmitted to cotton bolls. The two pathogens caused discoloration of the cotton seed and lint, which would eventually affect quality and yield of cotton. Weekly observations documented the progression of the disease in affected cotton bolls. Because only two of the four ingested pathogens were transmitted, efforts are underway to determine the fate of pathogens in the insect gut. These findings confirm the transmission of cotton disease by southern green stink bug and emphasize the need for controlling these new pests to minimize cotton yield losses.

Technical Abstract: Stink bugs have become problematic in cotton grown in the United States, and the occurrence of cotton disease has coincidentally increased. The objective of this study was to determine whether southern green stink bug (Nezara viridula) adults could acquire and transmit pathogens causing yield losses in cotton. For two days, southern green stink bug adults were fed green beans containing Pantoea agglomerans, P. annanitis, Klebsiella pneumonia, or Nematospora sp. in a laboratory. Additional cohorts of adults were fed sterile green beans as a control. Sterile green beans were then fed to the treated study insects and control insects for another four days. At the conclusion of feeding, adults were processed in the lab to determine acquisition potential of pathogens or placed on individual bolls to determine transmission of pathogens. Southern green stink bug adults acquired P. agglomerans and three other selected pathogens but only transmitted P. agglomerans and Nematospora sp. to cotton bolls. The transmitted pathogens caused necrosis or discoloration of cotton seed and lint. Bolls were also evaluated on a weekly basis to assess the progression of the disease. Additional studies are currently underway to localize pathogens in the insect alimentary system.