Laboratory and field evaluation of certain wild plant extracts against Aphis fabae Scop. (Homoptera: Aphididae) and its predators

Background Broad bean ( Vicia faba L.) is considered one of the most essential food crops in Egypt. Aphis fabae Scop. (Homoptera: Aphididae) causes a considerable damage to bean plants as well as to other leguminous crops. The present study dealt with laboratory and field trials to evaluate the effectiveness of some plant extracts against A. fabae and two predatory species. Results The effectiveness of six plant extracts viz Ballota undulata (BU), Teucrium polium (TP), Phlomis aurea (PA) (Lamiaceae), Pulicaria incisa (PI), Seriphidium herba-alba (SHA) (Asteraceae), and Euphorbia saint catherine (ESC) (Euphorbiaceae) against the bean aphid ( A. fabae ) and on the two predators, Chrysoperla carnea (Steph.) and Coccinella undecimpunctata L., was determined in both laboratory and field . Results showed that BU, TP, and SHA were the most toxic extracts to aphids, followed by PA and PI, while the ESC was the least toxic one. The lethal effects, expressed as percent mortalities, were 74.3, 73.2, 72.7, 65.9, 62.5, and 56.8%, respectively. All mortality rates were significantly different than the control. Regarding the effect on the predators, insignificant differences were observed between the tested extracts and the control. In the field, the tested plant extracts were efficient for controlling the aphid without a harmful effect on the predators. The extracts had a various positive effect on crop yield; it was increased. Conclusion The six tested plant extracts, evaluated against A. fabae , and two predatory species showed efficiency in aphid control and safety to the predators in the field.