Repellent, attractive, and insecticidal effects of essential oils from Schinus terebinthifolius fruits and Corymbia citriodora leaves on two whitefly species, Bemisia tabaci, and Trialeurodes ricini

In this study, the repellent, attractive, and insecticidal effects of essential oils (EOs) from Schinus terebinthifolius Raddi fruit and Eucalyptus citriodora Hook. (Corymbia citriodora (Hook.) K.D.Hill & L.A.S. Johnson) leaves on the sweet-potato whitefly (Bemisia tabaci Gennadius) and the castor bean whitefly (Trialeurodes ricini Misra) were evaluated. The olfaction response of B. tabaci and T. ricini was investigated under laboratory conditions by exposing adults to the odor of the EOs from S. terebinthifolius fruits and C. citriodora leaves using a specially designed glass olfactometer at five concentrations ranging from 0.01% to 1.0%. In addition, the insecticidal effect was evaluated under greenhouse conditions using five concentrations of EOs (25, 50, 100, 500 and 1000 ppm) applied in contact toxicity experiments. The results revealed that repellency or attractiveness of the tested EOs varied significantly according to the EO type, concentration, and whitefly species. The maximum insect attraction was obtained with 0.5% C citriodora leaf EO on T. ricini (229.03%). Conversely, the greatest repellency was observed with 1% S. terebinthifolius fruit EO on B. tabaci (37.84%). EOs from S. terebinthifolius fruit were the most potent against T. ricini adults, with an LC50 value of 19.622 ppm. Conversely, C. citriodora was less toxic for B. tabaci adults, with an LC50 value of 249.453 ppm, compared with controls. The present study suggests that the tested EOs may be suitable as alternative compounds in integrated pest management programs for B. tabaci and T. ricini. Moreover, their non-toxic and environmentally acceptable nature makes them safe to apply to plant crops. (C) 2017 Elsevier B.V. All rights reserved.