Effects of elicitor-mediated induction of plant defense on the growth of fall armyworm (Spodoptera frugiperda Smith)

Plants respond to insect feeding by activating signal pathways that result in the production of secondary metabolites that have been shown to reduce insect fitness, deter feeding, and attract beneficial insects.  Additionally, many organic and inorganic chemicals have shown to activate plant responses to pathogen and/or herbivorous arthropod attack when applied as a foliar spray or soil drench. Azelaic acid, benzothiadiazole, gibberellic acid (GA3), harpin, and jasmonic acid are thought to mediate plant response to pathogens and herbivores. The effect of these elicitors on the induction of plant defenses were determined by measuring the growth of fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) on four important crops, cotton, Gossypium hirsutum (Linnaeus.), corn, Zea mays (L.), rice, Oryza sativa (L.), and soybean, Glycine max (L.), treated or not treated with elicitors, under greenhouse conditions. As demonstrated in other studies, jasmonic acid consistently induced resistance to fall armyworm as manifested by growth of fall armyworm, particularly in cotton and soybean, whereas the other elicitors varied in their effectiveness. These observations led to a field experiment to determine the effect of jasmonic acid on the establishment and growth of populations of the two-spotted spider mite, Tetranychus urticae (Koch) (Acari: Tetranychidae), on cotton grown in the field. The findings provide further support that jasmonic acid facilitates changes in the plant resulting in increased resistance to arthropod herbivores.