Abstract: [Objective] This study aims to reveal the relationship of population dynamics of gypsy moth(Lymantria dispar) with nucleopolyhedrovirus(NPV) and induced-resistance of host plant. [Method] The effects of induced resistance of the green poplar (Populus cathayana) by jasmonic acid (JA) on development and nutritional utilization of gypsy moth larvae infected with and without LdNPV(Lymantria dispar nucleopolyhedrovirus) were studied in laboratory. Gypsy moth larvae were reared with artificial diets to the second instar and inoculated using a modified version of the diet plug method with 92 OBs·μL^-1 of LdNPV each larva. Larvae that had consumed the entire plugs were transferred to the green poplar seedlings induced with jasmonic acid or the normal green poplar seedlings (not induced with jasmonic acid) and fed on the seedlings up to the 3^rd instar. Larvae without inoculation with LdNPV and feeding on normal green poplar seedlings served as control. Larval body weight, leaves consumption, amount of feces were measured and efficiency of conversion of digested food of gypsy moth larvae were calculated, as well as the developmental duration was recorded. [Result] Larval development and nutritional utilization of gypsy moth were effected by LdNPV and the green poplar induced resistance by jasmonic acid (JA). The developmental duration, the relative growth rate, food utilization index of the group JA+V (larvae infected with LdNPV and fed on green poplar induced by JA) were decreased significantly compared with both the group V (larvae infected with LdNPV but fed on leaves of the green poplar) and the group CK (normal larvae fed on leaves of the green poplar). The larval developmental duration of the group JA+V was longer for 1.0 day, 1.2 day and 1.7 day than that of the group CK when fed on the poplar after JA inducing 1day, 5 days and 10 days, respectively. Larval weight of the group JA+V after induced 1 day, 5 days and 10 days decreased by 27.8%, 37.9% and 34.3%, respectively, compared with the group CK, by 11.8%, 18.2% and 14.4%, respectively, compared with the group V. The relative growth rates of the group JA+V after JA inducing 1day, 5 days and 10 days decreased by 46.3%, 58.1% and 58.8%, respectively, compared with the group CK, by 20.7%, 28.5% and 26.6%, respectively, compared with the group V. The approximate digestibility, the efficiency of conversion of ingested food, efficiency of conversion of digested food of the group JA+V and the group V reduced compared with the group CK, and the rank of three group was the group CK>the group V> the group JA+V. The food consumption of the group V is not differ significantly from that of the group CK. The food consumption of the group JA+V differed significantly from that of the group CK only when JA inducing 5 days.[Conclusion] The results suggested that induced resistance of poplar by exogenous JA may enhance the negative effects of NPV on development and the nutritional utilization of gypsy moth larvae.

Key words: jasmonic acide, induced resistance, Populus cathayana, Lymantria dispar, LdNPV, nutritional utilization