Behavior and biology of the tomato psyllid, Bactericerca cockerelli, in response to the Mi-1.2 gene

The Mi-1.2 gene, identified from wild varieties of tomato, Solanum peruvianum (Mill) (Solanaceae), has been incorporated into near-isogenic commercial varieties of tomato and has been shown to confer resistance to three different species of phloem feeders: aphids, whiteflies, and nematodes. The results presented here show that plants bearing Mi-1.2 were also resistant to the tomato psyllid, Bactericerca [Paratrioza] cockerelli (Sulc) (Homoptera: Psyllidae), a serious pest of tomato, Solanum lycopersicon (Mill), in the western half of North America. In choice studies, tomato psyllids preferred to settle on plants that did not contain the gene [Moneymaker (mi-1.2)] compared to near-isogenic plants with the gene [Motelle (Mi-1.2)]. As a result, total oviposition was higher on the susceptible variety, although no-choice studies indicated that there were no differences in numbers of eggs laid by individual females on either variety. Survival from egg to adult was higher on plants lacking the gene compared to plants containing the gene. However, there were no differences in total development time of individuals reared from either variety. The results suggest that mechanisms of resistance to the tomato psyllid observed in plants bearing the Mi-1.2 gene are distinct from the mechanisms of resistance to the three phloem feeders examined in other studies.