Preliminary Identification of the Sex Pheromones of the Citrus Fruit Borer (Citripestis sagittiferella Moore) Inhabiting the Mekong Delta of Vietnam

Author(s): Tran Trong Dung, Duong Kieu Hanh, Trieu Phuong Linh, Dinh Thi Chi, Tran Thanh Thy, Le Van Vang, Tran Vu Phen

Abstract
Citripestis sagittiferella is one of the most harmful pest insects of pomelo in the Mekong Delta of Vietnam. In order to utilize sex pheromone as tool for population monitoring by which supplies information for timing control, the sex pheromone of C. sagittiferella was preliminarily identified then tested under field condition. Fruits infected C. sagittiferella larvae were collected from pomelo orchards in Vinh Long and Hau Giang provinces and brought to Can Tho University laboratory for rearing to extract the pheromone. The analysis was conducted by GC-EAD, GC-MS and the double bond position was affirmed by analysis of its DMDS adduct. GC-EAD analysis resulted in three EAG-responses, namely component I (Comp. I), Comp. II and Comp. III. Mass spectra with diagnostic ions at m/z 61, 194 and 192 ([M-60]+ ions) indicated that they were unsaturated 14 carbons (C14) straight chain acetates. Reference to the synthetic standards by both GC-EAD and GC-MS analysis confirmed that the three pheromone components were (E)-11-tetradecenyl acetate (E11-14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (9Z,11E)-9,11-tetradecadienyl acetate (Z9, E11-14:OAc), respectively. Unfortunately, lures prepared from mixtures of synthetic E11-14:OAc, Z11-14:OAc and E9, Z11-14:OAc at several mixing ratios showed no attraction to C. sagittiferella males in field tests.