Friday, January 12, 2007 - 11:00 AM

Introduction of an Opportunistic Bacterial Cotton Pathogen Into Bolls by the Southern Green Stink Bug (Nezara viridula L.)

Enrique Gino Medrano, USDA-ARS-SPARC Cotton Pathology Research Unit, 2765 F and B Road, College Station, TX 77845, Jesus Esquivel, USDA-ARS-SPARC Areawide Pest Management Research Unit, 2771 F&B Road, College Station, TX 77845, and Alois Bell, USDA-ARS-SPARC, 2765 F&B, College Station, TX 77845.

In recent years, seed and boll rot associated with microorganism infections have had a significantly negative impact on cotton yield in southeastern Cotton Belt states. Based on Koch's postulates, we previously established that an opportunistic strain of the bacterium Pantoea agglomerans, originally isolated from a diseased boll from South Carolina, could reproduce the symptoms when inoculated into greenhouse-grown cotton bolls. A syringe and 28-gauge needle were used for inoculating a suspension of the bacterium through the carpel walls of bolls. Breaching of the carpel was necessary for disease to occur. Thus, we hypothesized that opportunistic microorganisms could be introduced into field grown fruit by cotton pests that feed by piercing/sucking mouthparts. The southern green stink bug (SGSB) was chosen as our model insect because of its mode of feeding and recently elevated pest status in cotton. Consequently, we determined that laboratory reared SGSB fed green beans soaked in a suspension of a P. agglomerans derivative marked with antibiotic resistance were capable of transmitting the bacterial pathogen into cotton bolls. The bacterial infection resulted in symptoms analogous to those observed in field samples. Pantoea agglomerans was introduced into bolls of various ages (1-, 2-, and 3-wk post-anthesis) by SGSB, and disease symptoms were temporally characterized (1-, 2-, and 3 wk) for each boll age category and these results will be presented.

Poster (.ppt format, 9251.0 kb)
Recorded presentation