Abstract: The dispersal direction of T. Chilonis in relation to wind speed and direction was investigated in cotton fields in Yucheng, Shandong Province in 1994 and 1995. The results showed that: (1) When the average wind speed (AWS) ranged from 1.1 rn/s to 1.6 m/s, the main dispersal direction was down the wind; when AWS was between 0.9 m/s and 1.1 m/s, the main dispersal direction was up the wind; and when it was about 0.6 m/s, there was no difference among the eight directions. (2) During the second generation of the cotton boUworm (before early July), the main despersal directions of T. chilonis were southwest and northwest; during the third genera tion before August, there was no main dispersal direction of the parasite; during the fourth generation (after the middle of August), the main dispersal directions were east, northeast and north.(3) Among all of the releasing experiments, the most urdavourable directions for dispersal of theparasite were west and south.

Key words: Trichogramma chilonis, cotton bollworm, dispersal direction , wind speed and direc- tion