BIONOMICS OF WEEVILS OF THE GENUS SITONA INJURIOUS TO LEGUMINOUS CROPS IN BRITAIN1

Abstract

SUMMARY. 1. Sitona hispidula is common throughout Great Britain upon clover and lucerne. The adults eat the leaves and the larvae damage the roots. Sitona sulcifrons is frequently abundant upon “seeds” clover and the larvae feed upon the root nodules. Sitona crinila frequents tares, clover, lucerne, etc., but is rarely sufficiently common to cause injury. The adults of S. hispidula are either fully‐winged or brachypterous and two forms of brachypterous wings have been observed in S. sulcifrons. The life‐history of these three species has been investigated in Britain for the first time. There is only one generation in the year. The adults live 12 months. The period of oviposition and the length of the egg, larval and pupal stages varies according to the species. The Braconids Perilitus rutilus Nees, P. cerealium Hal., P. aethiops Nees, Pygostolus falcalus Nees and a species of Liophron are recorded for the first time as parasites of the adult beetles. The fungus Botrytis bassiana (Balsamo) Montagne attacks these species of Sitona.