Influence of host plant species and plant nutrition on larval development of cutworms (Lepidoptera: Noctuidae)

Cutworms are a complex of generalist herbivores that affect multiple crops grown in North America. Early larval instars feed on foliage, whereas mature larvae eat into the stem and sever crop seedlings. Within this group, the redbacked cutworm (Euxoa ochrogaster) and pale western cutworm (Agrotis orthogonia) are the most widely distributed and economically important species in the Canadian Prairies. The objective of this study was to evaluate the effect of host plant species and plant nutrition on larval performance of both cutworm species. Larval development and preference were evaluated on three host species (canola, peas and spring wheat). The effect of plant nutrition on larval development was tested using two plant hosts (canola and spring wheat), exposed to varying fertilization regimes. Host species had no effect on developmental rate as measured by head capsule width across all instars for both cutworm species. Host species had a significant effect on larval weight per instar, developmental time per instar and pupal weight. Despite their generalist feeding behaviour, E. ochrogaster larvae performed better on canola and peas, than on wheat based on larval and pupal weight. A. orthogonia larvae performed better on wheat than on canola and peas based on larval and pupal weight. Further result will discuss the effect of plant fertilization on larval development, and the relationship between larval preference and performance between host species.