Larvae of the pea and bean weevil, <i>Sitona lineatus</i>, and the yield of field beans

Abstract

Summary In 16 experiments with field beans at Rothamsted, Woburn and Saxmundham between 1969 and 1976, seed-bed applications to the soil of dieldrin or γ-HCH were used to control subsequent infestations of the roots by larvae of Sitona lineatus . Rates of between 1·12 and 4·48 kg a.i./ha were used. Larval populations on untreated plots plots were variable, but 70–80% control was usually given by rates of 2·24–4·48 kg a.i./ha. Insecticides nearly always increased yields, the mean increase for all treatments being 0·15 t/ha, but a maximum yield response of over 0·5t/ha was achieved. It is suggested that the importance of S. lineatua larvae as pests of field beans in Britain has been under-rated.