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

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.