Comparative long-term protection provided against cowpea beetle by Acacia auriculiformis fractions and a chemical insecticide

The long-term protection of different fractions of Acacia auriculiformis was evaluated in the laboratory over the cause of six months at ambient temperature and humidity. Oil of the plant was fractionated into different fractions and fractions 1, 2, 4, 5, 6, 7, 8 and 10 were used at 50μl to treat cowpea seeds. Adult Callosobruchus maculatus was introduced at 2, 4 and 6 months of treatment and the effect of the fractions was observed on the oviposition rate and adult emergence of the insect as well as its ability to cause seed damage and weight loss. The result showed that the fractions of the plant were able to reduce or prevent adult emergence and the ability of the insects to cause seed damage and weight loss over the cause of 6 months. It was however, noted that the potency of the fractions reduced over period with the use of chemical insecticides. Fraction 1 which appeared to be most effective among the fractions of the plant, could be used for long-term protection of cowpea seeds as it offers similar result with the DDVP.