Pollinator management and insecticide usage within cocoaagroecosystem in Ghana

摘要

Ghana being a leading cocoa producer, depends heavily on pesticides although the crop is strictly entomophilous, primarily pollinated by ceratopogonid midges. This study in Ghana, investigated impact of confidor 200SL (Imidacloprid) and aqueous neem seed extract (ANSE) insecticides on abundance of pollinators and fruit-set in cocoa Three pollinator sampling methods (motorized aspirator, pan and McPhail traps) were used. Results show significantly more abundant midges on ANSE treated farms compared toconfidor treated farms, 2 (t = 4.34; df = 69; P < 0.001) and 60 - 120 (t = 1.85; df = 39; P < 0.041) days after spraying insecticides (DASI). Midge population recovered within 30 DASI under both insecticide treatments culminating in comparable abundanceover this period. Fruit-sets within 30 DASI were however significantly higher indicating that fruit-set is affected though midge population recovered. Although both insecticides were deleterious to the midges, ANSE was lesser and therefore preferred toconfidor. This result show both insecticides did not discriminate against beneficial insects, hence it will be important to consider a more comprehensive approach to the study of managing insect fauna complex within cocoa agroecosystem.