Abstract: The seasonal dynamics of vertical distribution and diapause syndrome of aestivation of wireworm in wheat field were investigated during 1988-1990.According to the population percentage in upper soil layer,its activity peaks were present in early spring and early summer,which synchronized phenologically with the growing stage of wheat and seedling stage of corn,respectively.During seedling stage of wheat in autumn,wireworm population in upper soil layer was the lowest of the year.Aestivation occured at the older,fully developed larvae stage,which was sensitive to higher temperature stimulus.The duration of aestivation persisted through autumn to early winter.Control measures were conducted in wheat field in accordance with these ecological characters and proved successful.

Key words: arid desert, biological soil crusts, nitrogenase activity, nitrogen fixation, environmental factor.