Castrillo, L.A.; Lee, R.E.* Jr.*; Lee, M.; Wayman, J.A.: Reduction of cold hardiness in overwintering Colorado potato beetles using ice nucleating bacteria

A key factor in the overwintering survival of Colorado potato beetle (CPB) is the regulation of the temperature at which the insect freezes. Like most overwintering insects, CPBs are unable to survive internal ice formation. Winter survival is enhanced by both burrowing into the ground and by lowering their supercooling point, the temperature at which ice formation spontaneously occurs in their body fluids. We have shown that the supercooling capacity, a major factor in winter cold hardening of CPBs, can be regulated by exposure to ice nucleating active (INA) bacteria. Ingestion of INA Pseudomonas fluorescens immediately elevates the beetle’s supercooling point. Furthermore, retention of the bacterium in burrowed CPBs’ guts through winter increases their susceptibility to sub-zero temperatures. Reduction of the CPB’s cold hardiness using INA bacteria offers a novel method for controlling these beetles by targeting the overwintering population.