EVALUATION OF COMPARATIVE EFFICACY OF SOME PLANT POWDERS FOR THE CONTROL OF CALLOSOBRUCHUS MACULATUS (F.) (COLEOPTERA: BRUCHIDAE) ON STORED COWPEA

EVALUATION OF COMPARATIVE EFFICACY OF SOME PLANT POWDERS FOR THE CONTROL OF CALLOSOBRUCHUS MACULATUS (F.) (COLEOPTERA: BRUCHIDAE) ON STORED COWPEA

Abstract:

Laboratory trials were conducted at the Department of Crop Protection, Institute for Agricultural Research, Ahmadu Bello University, Samaru- Zaria, to evaluate the efficacy of various plant powders (Neem Seeds and Leaves, Garlic bulbs, Orange peels, African Curry leaves, Onion leaves, African bush tea leaves, Lemon grass stem powders) and a conventional insecticide, Actellic dust, for the control of cowpea weevil, Callosobruchus maculatus (Fab.). Plant powders were applied at three concentrations: 2.5, 5.0, 10.Og per lOOg cowpea seed and actellic dust was applied at 1.0, 2.0 and 3.Og per lOOg cowpea seed. The criteria used for assessing the efficacy of these products included, mortality at 24 hours, 48 hours and seven days post treatments; oviposition rates; progeny development (F, F2, F3) , percentage cowpea damage and weight losses; seed viability, grain quality and taste, after three months of storage. The results showed that there was high mortality within 24 hours on cowpea treated with actellic dust at the highest level (3.0g w\w) which had 100 percent adult weevil mortality. African curry leaf powder (ACLP) at all three levels; Neem seed powder (NSP), Eucalyptus leaf powder (ELP); and Garlic Bulb powder (GBP) caused more than 45 percent mortality of bruchid at the highest level (10.Og w\w) within the same period. The critical period of adult weevils activity after emergence is within 48 hours. During this period, however, some of the plant extracts (such as NSP, ACLP, GBP, ELP, Lemon grass stem powder (LGSP) and Orange peel powder (OPP) recorded between 55.0 and 98.34 percent adult weevil mortality at the various treatment levels as compared with no deaths in the control. NSP achieved 100 percent inhibition of F, at the highest treatment level (10.Og w\w) compared with Actellic dust which recorded less than 75 percent progeny inhibition at the highest level. Other plant materials which had more than 50 percent inhibition of progeny development at the highest concentration included GBP, ELP, ACLP and NLP. The percentage damage and weight loss were least on cowpea treated with NSP at all treatment levels; followed by actellic dust and ACLP at similar levels. Actellic dust and powders of NSP, ACLP, NLP and GBP, LGSP, ELP, ABTP (African bush tea powder), OPP deterred ovipositon and larval development. Seed viability and grain quality were largely unaffected by the treatments when compared with the control. Generally, in all the parameters studied, these plant products and Actellic dust showed better performances as their treatment levels increased, suggesting that higher doses should be used (except for actellic dust) to establish the optimum concentration of powders that would be more effective than the ones used in the present trials.

EVALUATION OF COMPARATIVE EFFICACY OF SOME PLANT POWDERS FOR THE CONTROL OF CALLOSOBRUCHUS MACULATUS (F.) (COLEOPTERA: BRUCHIDAE) ON STORED COWPEA

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