Evaluation of predation potential of coccinellids on cassava whiteflies

Abstract

Two whitefly species namely Bemisia tabaci and Aleurodicus dispersus are common cassava pests in Kenya. As direct feeders on the phloem contents and vectors of viruses, whiteflies cause significant damage to the cassava crop in Kenya. This study aimed at evaluating the potential of coccinellidae beetles (Chelomenes vicina, Diomers flavipes, Diomers Hottentota, and Coccinella septempunctata) as predators of whiteflies. The predation potential of these predators was evaluated using nymphs of B. tabaci and A. dispersus under 'choice' and 'no choice' feeding conditions. The number of nymphs consumed by each individual predator was recorded after 24 h. Data collected from the 'no choice' and the 'choice' feeding experiments were analyzed using one-way ANOVA and paired-sample T-test, respectively. When the predators were exclusively provided with nymphs of B. tabaci, the number of nymphs consumed by the ladybird species was significantly (P<0.05) different. D.flavipes consumed the highest number of B. tabaci nymphs with a mean number of 79.4±1.1 nymphs. On the other hand, C. septempunctata consumed the highest number of A. dispersus nymphs with a mean of 2.5±0.2 in an exclusive feeding condition using A. dispersus nymphs. Additionally, when the predators were allowed a choice between B. tabaci and A. dispersus nymphs, all the four species of predators significantly preferred B. tabaci nymphs. The findings of this study indicate that the four ladybird species evaluated have potential and can be further evaluated and developed for the management of B. tabaci.