Abstract: Matsucoccus matsumurae is the external invasive pest endangering the pine tree， which occurred as over wintering generation and over summering generation annual. It is currently broken out with harm and presents the trend of spreading to north in Northeast China. With the latitude increasing， the summer heat condition meet its growth and development is becoming the foundation of its further harm and diffusion. To explore the lower limit of Matsucoccus matsumurae suitable temperature in Northeast China and figure out the range of its northward diffusion， a simulation experiment of four temperature gradients was conducted， meanwhile， its ability to resistance against high temperature was also tested. The results showed that Matsucoccus matsumurae grew with the fastest rate at 25℃， with the rate equivalent to that in the nature at 20℃， and a slow rate at 15℃. Matsucoccus matsumurae eggs hatched fairly slowly at 10℃， which impeded their normal growth and adult breeding. In conclusion，10℃ could be regarded as the low limit of temperature prohibiting northward diffusion of Matsucoccus matsumurae. In light of this temperature index， the summer climate of Northeast China was livable for over summering Matsucoccus matsumurae which might disperse northward further to the entire Heilongjiang province. High temperature tests revealed that Matsucoccus matsumurae inhabiting in Northeast China for long was highly resistant against high temperature and thus tends to survive and spread as before if they migrated to high temperature areas in South China. The results provided a theoretical foundation for exploring the lower temperature of suitable survival of the over summering generation of Matsucoccus matsumurae so that obtaining its diffusion areas northward and understanding its high temperature tolerance in Northeast China.

Key words: Temperature, Suitable for survival, Diffusion, Matsucoccus matsumurae, Impact