Abstract:Temperature is considered to be the key factor influencing the growth and development of Trichogramma dendrolimi.The correlation curve between developmental ratio and temperature is "logistic".The developing rates have great differences in various host eggs.The accumulated effective temperature for eggs of Antheraea pernyi,Lebeda nobilis and Dendrolimus punctatus are 179.4,170.3,161.5 day degrees respectively. Each day-degree is relative to the percentage of the development of T.dendrolimi.The optimum temperature is from 23—25℃ At 15℃ of constant temperature the average number of the bursting eggs of a single female is the largest,up to 7 eggs and the life of females can last 8.3days.At 25℃ of constant temperature the average ofthe of fsprings reproduced by a single female remains the most,up to 224. 8.But at 32℃ both the number of the bursting eggs and the number of the offsprings of a single female descent conspicuously. The ratio of the number of T.dendrolimi to the number of host eggs has a great influence upon the parasitizaon,the average number of emerging adults from each of host eggs and the viability of the next generation.When three kinds of host eggs are used as the hosts,the suitable ratio may be as follows:1:1 for eggs of Antheraea permyi;1:4 for eggs of Lebeda nobilis;1:10 for eggs of Dendrolimus punctatus. The egg-cards in which T.dendrolimi parasitized and deveioped for 2days had best to be stored in a ice-box,and the eclosion ratio of the eggs will be 78.62% after 60 days cold storage and 67.79% after 90days cold storade T.dendrolimi possesses the habit of copulating within the host egg immediately before emergence.90% of their eggs may be oviposited within 12 hours as soon as they find the host eggs after emergence.The number of eggs laid does not descent if they find their host eggs in 4 days after bursting the egg shells,but their parasitization will sharply become lower over 4 days after burst. Slope and its direction,canopy density,temperature for releasing, velocity and direction of wind and the density of host eggs can affect the spread distance of T.dendrolimi.At the optimum temperature with a breeze,an efficient distance within 15m and an vertical distance within 12m may be favourable.