The influence of methyl jasmonate (JA-Me) and B-glucosidase on induction of resistance mechanisms of strawberry against two-spotted spider mite (Tetranychus urticae Koch.)

The goal of the research was to study the influence of methyl jasmonate (JA-Me) and beta-glucosidase treatments on fecundity and preference to infestation and oviposition of two-spotted spider mite feeding on strawberry. The experiments were conducted in laboratory conditions on leaves of Aga and Kent cultivars. Leaves were treated with: a. solution of 0.1% JA-Me in 0.05% Triton X-100 (by spraying); b. beta-glucosidase dissolved in 0.1 M citrate buffer at pH 6 (by petiole); c. 0.05% solution of the Triton X-100 (by spraying); d. 0.1 M citrate buffer at pH 6 (by petiole). In the no-choice test, application of JA-Me on leaves of strawberry caused reducing of number of eggs laid during three days of the experiment. In the choice test, which was carried out for determination of non-preference mechanism of resistance, there was a statistically significant lower number of mites on leaves treated with JA-Me compared to leaves treated with other compounds as well as to non-treated leaves after 24 hours from solutions application. Moreover, at the same experiment, females of two-spotted spider mite laid the least number of eggs on leaves treated with JA-Me. Analysis conducted using liquid chromatography method, revealed increase of the level of phenolic compounds like chlorogenic acid and rutin on leaves treated with JA-Me. Thus, it appears that JA-Me may be involved in antybiosis or non-preference mechanisms of resistance of strawberry to two-spotted spider mite.