engleski

Climatic factors help predict stem weevils abundance

Biological and ecological features of the rape stem weevil (Ceutorhynchus napi) and cabbage stem weevil (Ceutorhynchus pallidactylus) are similar and they are often presented as a complex, although life cycles have important differences and demand different approach in their control. The critical point to determine the optimal time for insecticide treatment is the time of their migration into winter oilseed rape crops. Based on climatic factors various phenological forecasting systems have been developed and help producers to predict the date of pest immigration into crops. During four growing seasons, adult forms of C. napi and C. pallidactylus were trapped using yellow water traps at six locations within five Croatian counties with intensive oilseed rape production. The content of each trap was emptied once a week. Climatic data were obtained from the Croatian Meteorological and Hydrological Service for each year of the investigation and for each location. Exploratory data analysis, using regression tree analyses was done in R 2.30, applying the package “tree”. Factors that can help in prediction of appearance and abundance of C. napi are: the growth stage of oilseed rape plants, daily sunshine hours and mean daily air temperature ; for prediction of C. pallidactylus an additional important climatic factor was mean daily precipitation. Climatic factors are very important for migration of stem mining weevils from their hibernation places to oilseed rape fields and together with the growth stage of the crop are very useful in predicting the appearance of adult forms.

stem weevils; climatic factor; prediction; oilseed rape

nije evidentirano