Indigenous methods for bruchid beetle (Coleoptera: Bruchidae) control in stored beans (Phaseolus vulgaris L.)

Abstract

Four bruchid beetle control methods using: corn oil, wood ash, sunning and sieving (S&S) and insecticide (1.6% pirimiphos-methyl/ 0.3% permethrin ), were evaluated to determine their efficacy, effect on germination, seedling vigour and appearance of bean seeds. Efficacy was assessed by the percentage of damaged seeds and number of emerged bruchids in 250 g lots ofbean grain after 4 months ofstorage in glass jars in the laboratory. Germination was assessed by the percentage germination of groups of 10 clean seeds per pot in the greenhouse 7 days after planting. Seedling vigour was estimated by the fresh weight of 7 day old seedlings. There were significant differences among treatments in the percentage of damaged seeds ( P < 0.05) and emerged bruchids ( P < 0.001), but none in the germination and seedling vigour. Corn oil and S&S were as effective as insecticide in bruchid control, however S&S was the better of the two since it did not affect germination, seedling vigour or grain appearance. On-farm testing of S&S in 13 randomly selected farms showed that it was as effective as insecticide in bruchid control, however farmers preferred S&S due to its safety, low cost and maintenance of grain cleanliness.