Progress in the search for biological control agents of clover root weevil, Sitona lepidus (Coleoptera: Curculionidae)

Clover root weevil, Sitona lepidus (syn. flavescens) (Coleoptera: Curculionidae), has recently arrived in New Zealand. It has emerged as a pest of white clover (Trifolium repens) in the central North Island and appears likely to spread throughout the country. This contribution describes efforts made in 1998 to source biological control agents of S. lepidus from Europe and North America. Six species of parasitoids (one nearctic, five palaearctic) have been recorded in the literature as attacking S. lepidus. Three species which warrant investigation as candidate biological control agents were identified in this study. These were the palaearctic species Microsoma exiguum (Diptera: Tachinidae), Microctonus aethiopoides (Hymenoptera: Braconidae), and Pygostolus falcatus (Hymenoptera: Braconidae). Also, a preliminary description is provided of a disease which was observed to infect S, lepidus adults collected in California.