Induction of 2-cyanoethyl-isoxazolin-5-one as an antifeedant against the tobacco cutworm (<i>Spodoptera litura</i>) by jasmonic acid in sweet pea leaf

Although sweet pea (<i>Lathyrus odoratus</i>) beans contain toxic β-aminopropionitrile, the plant itself is readily attacked by insects and is, therefore, protected through the use of pesticides. Consequently, the induction of <i>L. odoratus</i> resistance to insect attack via exogenous treatment is promising for pest control development. Screening of inducible elicitor effects showed that treatment of sweet pea foliage with jasmonic acid (JA) can induce antifeeding-based resistance to tobacco cutworm (<i>Spodoptera litura</i>) larvae. Spectroscopic analysis identified 2-cyanoethyl-isoxazolin-5-one (2-CEIX) as the antifeedant with a half-maximal effective concentration of 33.6 µmol/g fr. wt., i.e., exogenous JA treatment induced antifeeding activity due to the accumulation of 2-CEIX. Moreover, 2-CEIX-induced mortality of <i>S. litura</i> larvae was evaluated by a dipping test and the half-maximal lethal dose was determined to be 5.9 mg/mL. Therefore, 2-CEIX was concluded to be a suitable induced resistance target for elicitors or a lead compound for insecticide development. Induction of 2-Cyanoethyl-isoxazolin-5-one as an antifeedant against the tobacco cutworm, <i>Spodoptera litura</i>, by jasmonic acid in sweet pea leaf.