ObjectiveThe induction and anti-insect effects of exogenous methyl jasmonate to larch were clarified, which will provide the theoretical basis for the ecological control of larch defoliator, through the study on the effects of exogenous methyl jasmonate (MeJA) on host selection behavior of Dendrolimus superans.

MethodDendrolimus superans, two-year-old seedlings of L. olgensis sprayed with different concentrations of MeJA, and the effects of these treatments on behavioral responses of the moth were tested by cages and Y-tube olfactometers.

ResultMeJA-treated seedlings repelled the female moth and made the moth lay lots of eggs on control seedlings. Compared with control, the oviposition percent of the female moth on 1, 5 or 10 mmol/L MeJA-treated seedlings decreased by 47.21%-77.03%, 43.18%-55.46% or 71.80%-80.08%; then the olfactory response ratio of the female moth on 1, 5 or 10 mmol/L MeJA-treated seedlings reduced by 49.24%, 59.71% or 43.68%-61.24%, and the higher concentration MeJA was used to treat the seedlings, the more obvious effect was observed on the behavior responses of the moth.

ConclusionThe MeJA-treated L. olgensis seedlings distinctly affect the olfactory and oviposition choice behavior of the female moth. While the stress responses of seedlings are relevant to the concentrations of MeJA, and the induced function of MeJA can last for 3-5 days.