Pathogenicity and Transmission of Cotton Seed & Boll Rotting Bacteria Vectored By the Verde Plant Bug

Caged field experiments and supporting laboratory work were conducted to characterize verde plant bug (Hemiptera: Miridae), a boll-feeding sucking bug, ability to vector cotton seed and boll rot pathogen. We used noninfected ‘clean’ verde plant bug from an established colony to study pathogenicity and transmission of a sequenced boll rotting bacterial pathogen, Serretia sp., previously isolated from bolls fed upon by verde plant bug.  Pathogenicity and transmission were measured on individual 3, 5 and 7-day old bolls post anthesis. Cotton boll injury and boll rot from the infestation of verde plant bug infected with Serretia sp. were significantly higher than non-infested (no bug)controls and non-infected verde plant bug. Transmission of the disease agent was consistently observed and recovered in all verde plant bug infected treatments across all boll ages assayed. Bacteria were not detected in locks with apparently undamaged lint and seed tissue.Differences in the magnitude of disease expression were detected in bolls as they matured. Pathogen transmissibility assays detected an ability for the verde plant bug to harbor the disease agent anywhere from 24h up to 96h post-infection and elicit disease. Several implications of this work on detection protocols and economic thresholds for this species complex will be discussed.