Abstract: Through the analysis of the historical data of Helicoverpa armigera oc currence and corresponding meteorological conditions in Shandong Province, the m ain meteorological factors affecting the occurrence of H. armigera were sele cted, and their affecting weight coefficients were determined by statistic metho d. Based on these, the grading domain values of the meteorological factors corre sponding to the occurrence grades of H. armigera were set off, and the forec ast model of meteorological grade of H. armigera occurrence trend was constructe d, which could offer a scientific basis for the control of H. armigera.

Key words: Plant growth regulator, Precursor, Zea mays, Growth, Nutrient uptake