The efficacy of methyl salicylate, an herbivore-induced plant volatile, to attract natural enemies of the soybean aphid, Aphis glycines Matsumura, in soybean fields

Herbivore-induced plant volatiles have been recently examined for their role in plant-plant and plant-insect communication. These plant volatiles, induced by the feeding of herbivores, are an integral component of plant defense. Their dual ability to act as signals for neighboring plants, preparing them for herbivore attack, and to attract natural enemies of herbivores, has been examined in both field and laboratory studies. One herbivore-induced plant volatile, methyl salicylate, has been shown to attract a variety of predators including predatory mites, predatory bugs, lady beetles, and lacewings, as well as parasitic wasps. In this study, experiments in progress have been designed to test the ability of synthetic methyl salicylate to attract natural enemies of the soybean aphid, Aphis glycines Matsumura, in organically managed soybean fields. Synthetic methyl salicylate lures have been deployed in treatment plots, with sticky traps placed to capture natural enemies at the methyl salicylate source and throughout the treatment and control plots. Whole plant samples are being taken to record additional natural enemies as well as soybean aphid populations. Also, sentinel plants with high soybean aphid populations, and baited with methyl salicylate, are being used to test the volatile’s ability to reduce soybean aphid populations. The results of these studies will be presented and the potential role for synthetic methyl salicylate in soybean aphid control will be discussed.