Effects of pasture and forage crop species on longevity, fecundity, and oviposition rate of adult white-fringed weevils Graphognathus leucoloma (Boheman)

Abstract

In an insectary experiment in which adult white-fringed weevils were fed on different plant species and cultivars, fecundity averaged 315 eggs per female on 12 legumes, 87 eggs per female on 4 brassicas, and 14 eggs per female on 12 grasses and cereals. The greater fecundity of individuals fed on legumes was due to both greater longevity and higher oviposition rate. These results appear to account for field observations that white-fringed weevil populations increase rapidly in pure legume stands and clover-dominant pastures but remain at low levels in pure grass swards. Within the legumes tested, sainfoin gave a significantly higher fecundity and longevity and Desmodium spp. a significantly lower oviposition rate (P < 0.05) than lucerne, Lotus spp., and Trifolium spp.