Feeding Rate of Larval Clover Root Curculio, Sitona hispidulus (Coleoptera: Curculionidae), on Alfalfa Taproots

Abstract

Larval clover root curculio (CRC), Sitona hispidulus (F.), were sampled with alfalfa host plants at intervals during the spring of 1983. Relationship between larval days (a measure of larval density over time) and amount of taproot damaged by larvae was determined. CRC damaged alfalfa taproots at the rate of 13.03 and 4.35 mm2 per larva per day for fourth and fifth instars, respectively. Second- and third-instar CRC did not contribute significantly to taproot damage. Feeding rate for fourth-instar CRC was estimated at 5.68 and 1.70 mg per larva per day for fresh and dry weight, respectively. The rate for fifth instars was estimated at 1.90 and 0.57 mg per larva per day for fresh and dry weight, respectively.