The growing abundance of Helicoverpa armigera in Hungary and its areal shift estimation

The invasive Cotton Bollworm (Helicoverpa armigera Hubner, Lepidoptera: Noctuidae) has become a serious pest of several agricultural plants since its first mass occurrence in Hungary (1993). During the decades of the species' presence in the Carpathian Basin, a remarkable fluctuation was detected in its abundance and flight phenology. We analysed long term light trap records and meteorological data to identify the possible factors behind these fluctuations. This study presents an overview of the areal dispersion and the rate of accumulation and flight phenology of this invasive pest, from its first Hungarian mass occurrence until the present, focusing on the influence of climatic factors on the Hungarian distribution of H. armigera. According to our estimation, this pest occupied 94% of the area of Hungary within eight years. There were significant differences in pest pressure by regions, corroborated by the average number of trapped specimens and the regression coefficients. Fluctuations of specimen numbers in the different years are clearly visible in the flight phenology diagrams, which depend on the rate of the growing abundance. The results indicate that abiotic elements may also play a significant role in the areal dispersion of this important invasive insect.