Efficacy of three plant extracts on insect pests of three vegetables
The efficacy of Vernonia amygdalina, Momordica charantia and Morinda lucida extracts were tested for insecticidal activities on insect pests of Corchorus olitorus, Amaranthus cruentus and crucumis sativus. Twenty grammes of each botanical were soaked in hot water at 1000C, allowed to cool for 24h and filtered. The extracts were used on the vegetable crops, Cypermethrin [a sythenic insecticide] was used to compare the efficacy of the extracts while distilled water was used as the control. The experimental design was randomized complete block in 5 x 3 factorial layout. Insect count were taken on the vegetable crops at 5.6 and 7 weeks after planting [WAP]. The botanical and cyermethrin significally reduced the number of insect on the vegetables compared with the control. The average percentage efficacy were: Cypermethrin [85.06%], V amygdalina [71.40%], Momordical charantia [65.16] and Morinda lucida [59.89%]. There was no significant difference in insect population count on the three vegetables at 5 and 6 WAP. Insect population found on C. Olitorus and A. Cruentus were significantly higher than those found on C.sativus at 7 WAP. The plant extracts proved effective in controlling insect, pest on these vegetables and are therefore recommended for use by farmers.