FACTORS AFFECTING REARING OF CLOVER ROOT CURCULIO (COLEOPTERA, CURCULIONIDAE) IN CONE CONTAINERS

A rearing technique for clover root curculio, Sitona hispidulus (F.), was developed using legumes growing in cone containers in the growth c hamber. Eight factors were tested for their effect on rearing clover r oot curculio from egg to adult: (1) sterilization of egg surfaces, (2) egg infestation rate, (3) egg age, (4) plant growth media, (5) plant age at time of infestation, (6) watering schedule, (7) legume species and infestation rate with eggs or larvae, and (8) number of holes for infesting plants with larvae. The four most important factors for impr oving larval growth and survival of adults were as follows: (1) egg in festation rate, (2) egg age, (3) sterilization of egg surfaces with ei ther laundry bleach or ethanol or both followed by a sterile water rin se, and (4) a pear-vermiculite mixture as a plant growth medium. Legum e species (white clover [Trifolium repens L.], red clover [T. pratense L.], and alfalfa [Medicago sativa L.]), watering schedules (two, thre e, or seven times a week), and number of holes for placing larvae in t he soil had little or no impact on survival. Survival was improved by using eggs rather than larvae to infest plants. Five or more eggs per plant increased abnormalities in adults. Usually, insect survival was reduced with increasing number of eggs (10 or more per plant). Taproot injury increased with increasing numbers of eggs, but not larvae, per plant. There was 30-50% recovery of males and females. Previously pub lished methods reported only a maximum of approximate to 20% survival from egg to adult.