ATTRACTION OF WHITE FLY Aleurodicus cocois (HEMIPTERA: ALEYRODIDAE) MEDIATED BY CASHEW TREE VOLATILES

Abstract

Naturally the plants produce different mixtures of volatile organic compounds (VOCs) such as monoterpenes, sesquiterpenes, aldehydes and green leaf volatiles (GLVs). In this work, it is hypothesized that the attraction of Aleurodicus cocois depends in part on volatile emissions of cashew plants and, therefore, we aimed to characterize the volatile organic compounds (VOCs) emitted by dwarf cashew clones, and to evaluate the response behavior of A. cocois against these compounds. A four-arm olfactometer was used to investigate the response of A. cocois adult females to volatile leaf compounds of CCP 76, EMBRAPA 51 and PRO 143/7 previously identified as susceptible and resistant to insect, respectively. The volatile compounds emitted by the leaves of the three cashew clones were analyzed by solid phase microextraction coupled to GC-MS. Bioassays revealed that CCP 76 volatiles were attractive to A. cocois, whereas volatiles of EMBRAPA 51 and PRO 143/7 were less attractive to insects when compared to a control (air). According to the principal components analysis, the compounds careno δ-2, careno δ-3, limonene, terpinolene, α-copaene, β-caryophyllene β-ocimene, allo-ocimene, neo-allo-ocimene, α-pinene and myrcene were emitted at intermediate levels by clone CCP 76 compared to EMBRAPA 51 and PRO 143/7. The results suggest that volatile constituents of cashew are determinant factors in the selection of host plants by A. cocois and that the susceptibility of clone CCP76 to this insect may be associated with chemical factors by the release of attractive volatile compounds in moderate concentrations.