Differences in the susceptibility of five herbivore species and developmental stages to tomato resistance induced by methyl jasmonate treatment

We compared the susceptibility of five herbivores to tomato resistance induced by methyl jasmonate (MeJA) treatment. We tested for lethal effects against five herbivores (Spodoptera litura, Mamestra brassicae, Frankliniella occidentalis, Tetranychus urticae, and Henosepilachna vigintioctopunctata) at various MeJA concentrations. The mortality of all five herbivores increased significantly with increasing MeJA concentration. The 25 % lethal concentration was 0.03 μM for both first-instar larvae of S. litura and third-instar larvae of M. brassicae, 0.51 μM for third-instar larvae of S. litura, 0.76 μM for adult T. urticae, 2.4 μM for first-instar larvae of F. occidentalis, and 5.7 μM for first-instar larvae of H. vigintioctopunctata. Thus, the degree of susceptibility to MeJA-induced resistance of tomato was first-instar larvae of S. litura = third-instar larvae of M. brassicae > third-instar larvae of S. litura ≈ adult T. urticae > first-instar larvae of F. occidentalis > first-instar larvae of H. vigintioctopunctata. Mortality of first-instar larvae of M. brassicae was >90 % at all concentrations. Mortality of fourth-instar larvae of H. vigintioctopunctata (<7 %) was similar to that of the control at all MeJA concentrations. We also detected statistically significant weight loss of the surviving lepidopteran larvae, increased larval duration of F. occidentalis and H. vigintioctopunctata, and reduced egg production by T. urticae grown on MeJA-treated tomato, suggesting that the MeJA-induced resistance can control these herbivores, but effectiveness is different on different species and growth stage. Feeding by both M. brassicae and H. vigintioctopunctata larvae activated JA-inducible genes in tomato.