| Summary: | Two strains of plant growth-promoting rhizobacteria, Pseudomonas chlororaphis (PA23) and Bacillus amyloliquefaciens (BS6), can control some fungal diseases of canola through production of bacterial metabolites and through induced systemic resistance, which is initiated by the signalling molecule jasmonic acid. Direct application of jasmonic acid activates defence-related compounds and influences insect herbivory in canola. Field and laboratory studies investigated the effects of the two bacteria and of jasmonic acid on insects of canola. In the field there were no consistently significant effects of treatment on insects sampled by beat cloth or sweep net, level of flea beetle injury, canola yield or quality. In the laboratory, jasmonic acid significantly increased oviposition and decreased larval feeding in diamondback moth (Plutella xylostella) and slowed development and reduced reproduction in turnip aphid (Lipaphis erysimi). The effects of jasmonic acid on canola were systemic. Analysis of leaf tissue showed significant effects of treatment on defence-related compounds.
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