Distribution and biological control significance of Colorado potato beetle spiroplasmas in North America.

Abstract The Colorado potato beetle spiroplasma, a helical wall-less bacterium, attaches to the midgut of larval and adult Leptinotarsa decemlineata (Say). Despite its lack of pathogenicity to the beetle, its host specificity and ease of transmission may prove useful in biological control if insecticidal genes (e.g. the Bacillus thuringiensis subsp. tenebrionis δ-endotoxin gene) can be incorporated into its genome. Toward this goal, Colorado potato beetles were collected from various sites in North America and examined for spiroplasmas. Spiroplasmas were observed in the gut contents of L. decemlineata adults collected in Canada (Alberta and Quebec) and the United States (Arizona, Maine, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New Mexico, New York, North Carolina, Utah, and Washington) and from L. texana Schaeffer adults collected in Texas. None were naturally associated with adults of the related species, Doryphora quadrasignata Germar, collected in Brazil. Seven isolates adapted to insect cell-free media are now available for molecular studies.