Influence of sulphur plant nutrition on oviposition and larval performance of the cabbage root fly

Abstract 1 Oilseed rape plants ( Brassica napus ) (L.) (Brassicaceae) were grown under different levels of sulphur supply and tested for the oviposition preference and larval performance of cabbage root flies Delia radicum (L.) (Diptera: Anthomyiidae). 2 Adult females laid more than three‐fold as many eggs on control S n (normal field concentration) than on sulphur‐free S 0 plants. By contrast, no significant difference was observed between control and double normal concentration (S + ) plants. 3 The larval performance was evaluated using three additional, intermediate sulphur levels between S 0 and S n , and the plants were infected with equal numbers of eggs. The percentage pupation at the end of larval feeding ranged from 6% (S 0 ) to 32% (S n or S + ) and the average number of pupae, or of emerging flies, was significantly correlated with sulphur application. 4 The weight of emerging males and females was correlated with plant sulphur supply. 5 The duration of development from eggs to adult emergence was approximately 2 days longer in females than in males. Females originating from plants with a normal or higher sulphur supply tended to emerge 1–2 days earlier.