Integrated field management of cowpea pests using selected synthetic and botanical pesticides

This study evaluated the effect of integrating synthetic and botanical pesticide sprays in the management of cowpea (Vigna unguiculata) field and storage pests. Cypermethrin (Ambush CY 5% EC) and unitary crude concoctions of tobacco (Nicotiana tabacum) were used as the synthetic and botanical pesticides, respectively. Treatments were applied at budding, flowering, pod formation, pod filling and pod physiological maturity. The control was untreated cowpea. Cypermethrin was more effective than tobacco and resulted in decreased pest densities and better yields. Tobacco was beneficial only when the latter was applied at the podding stages, tobacco being ineffective against the flower thrips. Applying tobacco at the podding stages significantly reduced pod pests and Callosobruchus maculatus infestation in storage. Use of synthetics and tobacco was more economically beneficial than using synthetics alone. Since the yield difference between the cypermethrin treated plots and those treated with cypermethrin followed by tobacco did not offset the expense of cypermethrin, botanical pesticides could substitute for synthetic pesticides at the podding stages for control of pod pests when absolute pest control is not important.