In laboratory experiments, we identified and quantified volatiles emitted by inflorescences and berries of two grape varieties (Trebbiano and Sangiovese) and examined the effects of the volatiles on oviposition by the grapevine moth Lobesia botrana; compared to Trebbiano, Sangiovese is relatively more susceptible to L. botrana infestations. Chemical and electrophysiological analysis indicated only quantitative differences between the volatiles released by the two varieties. In a dual-choice oviposition bioassay based only on volatile cues,females did not show any preference between the two varieties. The six major components of the odour profiles that were GC-EAD-active to female antennae included: (S)-(-)-limonene, 4,8-dimethyl-1,(E)3,7-nonatriene, (±)-linalool, (E)-caryophyllene, (E,E)-α-farnesene, and methyl salicylate. At the beginning of the berry touch phenological stage, their proportions were about 10:0.6:0.4:0.5:0.9:0.6 in Trebbiano and 10:1:0.4:1.5:0.4:0.3 in Sangiovese. A six-component synthetic lure (with the proportion 10:1:1:1:1:1, which approximated the ratio of components released by both varieties) was used in further laboratory oviposition bioassays; depending on its dosage, the synthetic lure either attracted or repelled oviposition. In release-capture experiment conducted in a field cage covering two grapevine rows, the synthetic lure was more attractive than a grape cluster or a blank control and stimulated oviposition on the vegetation near the lure. The results indicate that L. botrana uses olfactory cues to select oviposition sites and that an artificial lure, containing the major volatiles released by two grape varieties, may be useful in monitoring female numbers in the field.
|Titolo:||Plant odours attractive to Lobesia botrana mated females. Second Conference on pheromones, food lures, traps and biological control: alternatives for the 21th century.|
|Anno del prodotto:||2010|
|Appare nelle tipologie:||5.12 Altro|