Abstract: Insect distribution type is one of the population attributes,which is of significance either in theoretical ecology or in pest forecast and control.Wheat stem maggot(Meromyza Sultatrix Linne)is the main pest of spring wheat in the west of Inner Mongolia.This pest reduced spring wheat production by one hundred million kg.in this region in 1978.We made an investgation and analysis on the field distribution types of wheat stem maggot ova in six plots of three different places in 1980-1981.The results are follows:1.Wheat stem maggot ova and oval stems were both of gathering distribution in the field and accorded with the negative binoial distribution.The results of M-Mregression analysis are α=0.4633>0 and β=1.081>1.2.By testing the normal independence we found the data of the oal stems are:log(x+1/2)and log(x+k/2).3.By calculating the number of oval stems to determine the control standard,the question of sequential sampling was used:d1=0.3895n-4.55 and d2=0.3895n+4.55.

Key words: Wheat stem-maggot, pest forecast