Induced resistance involves plant-mediated changes associated with initial attack by herbivores and pathogens that negatively influence subsequent attackers. The jasmonate pathway and the salicylate pathway (conditioning systemic acquired resistance, SAR) are two of the biochemical response mechanisms that can be triggered by various attackers. The materials evaluated in these trials include Coronalan, a synthetic JA mimic; Actigard, which elicits SAR; and Messenger, which triggers responses that stimulate both the salicylate pathway and the jasmonate pathway. These materials were evaluated in laboratory and field trials to measure their impact on western flower thrips feeding and transmission of tospoviruses.

Laboratory trials were conducted to determine optimum rates to use for each inducer. Feeding reductions were observed with all inducers. Based on these laboratory results, Coronalan, Messenger, and Actigard were evaluated in subsequent field trials, at the rates of 0.2 oz/acre, 4.5 oz/acre, and 0.5 oz/acre, respectively. Phytotoxicity effects were not observed in trials with field grown chrysanthemums. There were no significant differences observed in fresh weight, dry weight or height between any of the treatments. Differences were observed between treatments in the number of flowers per plant, but none of the treatments were significantly different from the control.