Pine coneworm, Dioryctria pryeri Ragonot (Lepidoptera: Pyalidae), as an important insect pest of the cones and shoots in Chinese pine, Pinus tabuleaformis Mill., tends to select the cones previously damaged by Gravitarmata margarotana (Heinemann) for feeding and oviposition. In the present study, the inhibition of pine coneworm on larvae G. margarotana induced defenses of P. tabuleaformis and mechanism of the herbivore-induced negative defenses was explored in the pine coneworm and Chinese pine (two years old cone and shoot). The result indicated that diterpene resin acid was mainly constructive and induced defense compounds, and it increased significantly in both cones and shoots after damaged by the coneworm. The concentration of resin acid dropped to its normal state after 10 days in the infested cones, whereas it remained in the same high level in the infested shoots after 10 days. We also compared the activity of glucose oxidase (GOX) in salivary gland of larvae D. pryeri among three groups: the cones previously infested by G. margarotana, the cones and shoots. The activity of GOX is significantly higher in the 5^th instars than it in the 4^th and 3^rd instars. In the same instars, the activity of GOX of larvae D. pryeri is the highest in the cones previously infested by G. margarotana group, and the lowest in the shoots group. These result revealed that host terpene defense response was suppressed gradually by the GOX enzyme of pine coneworm. By comparing of the RNA and P content, we found significant difference among the 3^rd, 4^th and 5^th instars. The 3^rd instars had the highest RNA and P content, whereas the 5^th had the lowest. Within the same instars, there was no significant difference in the larvae D. pryeri intake of infested cone by G. margarotana, the cone or shoot. All those results showed that larvae G. margarotana induced host defense responses in the early stage, then larvae D. pryeri suppressed the resin acid defense of Chinese pine by using the GOX enzyme. As the result, there are no significantly difference in the growth rate among the larvae D. pryeri intake of in the cones previously infested by G. Margarotana, the cones and the shoots.