Acetone and ethanol extracts of the leaves of eighty plant species, belonging to seventy-three genera and forty-three families were bioassayed on adult Tribolium castaneum (Herst) by spraying a series of concentrations directly on the beetles under a Potter's tower. The highest concentration (20%) of the crude extracts of only four plants, Artocarpus incisa, Capsicum annuum, Cuscuta americana and Nicotiana tabacum inflicted 80 - 100% mortality in five days. About 47 to 67% mortality was recorded with the extracts of Annona reticulata, Bontia daphnoides, Eupatorium odoratum, Gliricidia sepium and Hibiscus rosa-sinensis, while the other seventy-one plants were relatively ineffective.