| Abstract: | Based on historical records, cutworm attack levels for the years 1906 to 1979 have been estimated on a scale from 1 to 11 for Denmark as a whole. By means of linear regression methods the attack levels were related to monthly values of ordinary climatic variables. A resulting model of 8 variables could account for 64% of the total variation of attack level. The model showed a reducing effect on attack level of the amounts of precipitation during late winter and during May. For June, July and August the reducing effect of the numbers of precipitation days was stronger than that of the amounts of precipitation. Soil moisture as a mortality factor for larvae and pupae is suggested as the reason for the influence of precipitation during late winter and May, while rain in the summer may decrease flight, mating and oviposition of the adults. |
