Resistance to Anthonomus rubi in the cultivated strawberry

The strawberry blossom weevil (Anthonomus rubi) is a common pest in UK strawberry plantations which has become more serious in recent years. It causes most damage in late-flowering short-day cultivars or in spring-planted waiting-bed plants or day-neutrals. Between 1990 and 1993 the level of blossom weevil damage observed on various late flowering cultivars and selections in cultivar trials was found to vary considerably. Severed flower buds on cv. Pandora was estimated at 0-5% but numbered selections flowering concurrently had up to 50% severed buds. Furthermore, the progeny of crosses between different late-flowering selections appeared to be segregating for the observed level of blossom weevil damage. In 1995 the progeny from eleven crosses were assessed for their susceptibility to blossom weevil attack in both a glasshouse and a field experiment. Potted plants in the glasshouse were artificially infested with mature weevils at the rate of circa one weevil per plant. Unexpectedly, the level of damage to flower buds observed was very low and no differences between the families were detected. Contrastingly in the field experiment, where a natural infestation was allowed to develop unchecked, widespread damage to buds was observed and there were significant differences between families for levels of damage. The results suggest that the proportion of damaged buds is not merely a function of flowering time but that susceptibility to A. rubi is under independent genetic control.