DISTRIBUTION AND ABUNDANCE OF SITONA HISPIDULA (F.) AND THE EFFECT OF INSECT INJURY ON ROOT DECAY OF RED CLOVER IN THE MARITIME PROVINCES

Abstract

Insect injury to red clover by root-feeding weevils, mainly the clover root curculio (Sitona hispidula (F.)), and the association with root decay were investigated by periodic examinations of roots during 1965 and 1966. The abundance of Sitona spp. was also recorded from soil samples taken with the root samples. Greatest injury to the roots was observed during June and July of the first year of production, when larval populations were highest. The period of most rapid increase in the external decay of roots coincided with peak larval populations and the resulting increase in feeding injury. With increased severity of insect injury the external decay and, to a greater extent, the internal decay increased. During the period of these studies S. hispidula was widely distributed throughout the Maritime Provinces and was sufficiently abundant to be considered of economic importance.