Effect of spraying plant extracts on seed yield, quality and insect infestation of some cow pea cultivars

The present investigation was conducted at E1-Serw Experimental Agricultural Research Station (ARC) during the summer seasons of 2007 and 2008 to study the effect of spraying plant extracts on seed yield, quality and insect infestation of cow pea cultivars. The study included four cow pea cultivars i.e. Buff, Cream, Brabham and Local and four spraying treatments (black pepper seed extract, neem seed extract, Malathion 57 % pesticide and control (without spray). Seeds of each plot were stored for 3 and 6 months after harvest. The experimental design was arranged in strip plot design with three replicates. Buff cultivar surpassed the other cultivars in total fresh forage and dry yields, seed yield, germination percentage and the lowest values of insect infestation and seed dry weight loss. The same cultivar maintained its superiority in crude protein, tannins, total phenols and vicine contents. Spraying with Malathion 57 % gave the highest values of germination percentage and the lowest values of insect infestation and seed dry weight loss. The same treatment gave the highest values of chemical constituents. The germination percentage of cow pea seeds were decreased and insect infestation percentage and seed dry weight loss were increased as the storage period increased from zero to 6 months. Increasing the storage period from harvest to 6 month, reduced gradually total carbohydrates, tannins, total phenols and vicine and increased crude protein content. Insect infestation and seed dry weight losses had significantly negative correlation with seed contents of tannins, total phenols, vicine as well as germination percentage. The results revealed that, spraying cultivar Buff plants during flowering and pod filling stages with neem and black pepper seed extracts could substitute the spraying Malathion 57% to protect cow pea seed from weevils' infestation and hold seed quality for six month.