Chemical control of the pea and bean weevil, <i>Sitona lineatus</i> L., and subsequent effects on the yield of field beans <i>Vicia faba</i> L.

Abstract

SUMMARY Methods of controlling Sitona lineatus adults and larvae were tested in 13 experiments on spring-sown beans, four on autumn-sown beans and two on dry-harvested peas. A total of 16 insecticides were used, though not all combinations of insecticide, application method and crop were tested. Applications included granules or sprays to the foliage, seed-bed treatments, seed-furrow treatments and seed treatments. Phorate as a furrow treatment at sowing at 1·24 kg a.i./ha increased yields of spring-sown beans by an average of 0·5 t/ha but was not persistent enough to protect autumn-sown beans from attack. Foliar applications of systemic insecticides (carbofuran or carbosulfan) at similar doses decreased attacks but effects on yield need further evaluation. Preliminary work indicates that seed-bed or furrow treatments of phorate can also be used to control S. lineatus on peas.