A survey of insect pests and farmers' control measures on snap beans in Kirinyaga District, Kenya
Kwasi O, Ampofo James
J J, Anyango
John H, Nderitu
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A survey was carried out in 99 out of about 1000 snap bean farms in Mwea Division, Kirinyaga District during January and February 1993 to identify pest and disease problems encountered in snap bean, production and the management strategies adopted by farmers. The main pests on the farms were bean stem maggots (Ophiomyia spp), whiteflies (Bemisia tabaci [Gen]), thrips (Megalurothrips sjostedti [Trybom]), red, spider mites (Tetranychus spp.) and spiny brown bugs (Clavigralla (Acanthomia) horrida [Germ] and Clavigralla tomentosicollis [Stal]). Angular leaf spot and bean rust are the main diseases on snap beans in the area. It was observed that farmers knew their pests and diseases well and were able to rank them fairly accurately for level of importance. Farmers were keen on achieving high yields of unblemished pods, and used high rates of external inputs to achieve this. They saw pesticides as an insurance for a "quality" produce and relied heavily on synthetic products to grow and protect their crops. Some 36 insecticides and fungicides were used regularly by farmers, who employed up to 15 foliar sprays during a single crop cycle. Some of the pesticides were, ineffective as a result of adulteration or decay due to age. Farmer decisions on pesticide application often were not based on knowledge of the pest population density or control thresholds, but on planned calendars of operation. Farmers appeared to ignore or lack knowledge on how to spray, use of protective clothing, use of pesticides for specified pests, proper rates of application, formulations and concentrations.