We demonstrate specific mechanisms through which a bacterial plant pathogen induces plant responses that modify behavior of its insect vector. <i>Candidatus </i>Liberibacter asiaticus, a fastidious, phloem-limited bacterium responsible for causing huanglongbing disease of citrus, induced release of a specific volatile chemical, methyl salicylate, which increased attractiveness of infected plants to its insect vector, <i>Diaphorina citri</i>, and caused vectors to initially prefer infected plants. However, the insect vectors subsequently dispersed to non-infected plants as their preferred location of prolonged settling because of likely sub-optimal nutritional content of infected plants. The duration of initial feeding on infected plants was sufficiently long for the vectors to acquire the pathogen before they dispersed to non-infected plants, suggesting that the bacterial pathogen manipulates behavior of its insect vector to promote its own proliferation. We are currently exploring whether masking the environment with large amounts of methyl salycilate may prevent vectors from homing in on bacterially infected trees analogously to the mating disruption technique. Preliminary evidence suggests that we may be able to reduce the vector’s ability to discriminate between infected and uninfected trees, potentially reducing pathogen spread.
