Essential host plant cues in the grapevine moth

Abstract

Host plant odours attract gravid insect females for oviposition. The identification of these plant volatile compounds is essential for our understanding of plant-insect relationships and contributes to plant breeding for improved resistance against insects. Chemical analysis of grape headspace and subsequent behavioural studies in the wind tunnel show that host finding in grapevine moth Lobesia botrana is encoded by a ratio-specific blend of three ubiquitous plant volatiles. The odour signal that attracts mated females to grape consists of the terpenoids (E)-beta-caryophyllene, (E)-beta-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene. These compounds represent only a fraction of the volatiles released by grapes, and they are widespread compounds known throughout the plant kingdom. Specificity may be achieved by the blend ratio, which was 100:78:9 in grape headspace. This blend elicited anemotactic behaviour in moths at remarkably small amounts. Females were attracted at release rates of only a few nanograms per minute, at levels nearly as low as those known for the attraction of male moths to the female sex pheromones.

Oriented responses of grapevine moth larvae Lobesia botrana to volatiles from host plants and an artificial diet on a locomotion compensator

“…In wind tunnel studies, mated females showed upwind flight to different parts of the grapevine (Tasin et al, 2005;Masante-Roca et al, 2007), to an extract of the headspace volatiles of grapes (Tasin et al, 2006a,b) as well as to a synthetic blend of ten compounds present in grape headspace vapour that elicited significant antennogram responses from L. botrana (Tasin et al, 2005(Tasin et al, , 2006a. Similar upwind responses could be shown to a mixture of (E)-b-caryophyllene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E)-b-farnesene presented at the ratio found in grape headspace vapour (Tasin et al, 2006b(Tasin et al, , 2007.…”

“…For the mixture of 1-hexanol plus terpinen-4-ol tested at two source doses (50 ng + 50 ng and 100 ng +100 ng), a significant decrease in target vector was recorded after removal of the mixture at the lower dose (Table 1) and the target vector value recorded during exposure to vapour from the lower source dose was significantly higher (p < 0.05) than that recorded at the higher source dose. No behavioural effects were recorded for the ternary mixture of (E)-b-caryophyllene + DMNT + (E)-bfarnesene (Table 1) which is attractive to female L. botrana (Tasin et al, 2006b(Tasin et al, , 2007. Table 2 Upwind displacement calculated for tracks of L. botrana larvae walking on a locomotion compensator in an air stream alone (Pre-exposure), in response to the odour of the artificial diet and to single host plant compounds added to the air stream (Treatment), and after removal of the treatments (Post-exposure).…”

Host plant volatiles serve to increase the response of male European grape berry moths, Eupoecilia ambiguella, to their sex pheromone

“…A mixture of the three most abundant volatiles at the ratio occurring over grape berries, i.e. (E)--caryophyllene, DMNT, and (E,E)--farnesene at 100:78:9, was attractive to female L. botrana whereas another mixture of these three compounds at 37:17:100 found over apples was not (Tasin et al 2006b(Tasin et al , 2007. Although these studies and our own underline the importance of appropriate ratios, one could expect the ratio of plant volatiles needed for attraction to be less strict than the ratio of components in a species speciWc pheromone blend considering the range of host plants exploited.…”

Modulation of Protein Phosphorylation, N-Glycosylation and Lys-Acetylation in Grape (Vitis vinifera) Mesocarp and Exocarp Owing to Lobesia botrana Infection

“…Adult L. botrana oviposits on the grape berries and it causes direct damage to clusters when larvae feed within the berries, and indirect damage by fungal infestation of injured berries by Botrytis and other secondary fungi such as Aspergillus, Alternaria, Rhizopus, Cladosporium, and Penicillium (16). Even though improvements in the management of this pest have been reported using insecticide (17) and pheromone-based strategies (18), little is known about the signaling mechanisms in grapes in response to L. botrana. Therefore, a comprehensive quantitative description of the molecular events that change is important to obtain biological insight into the infection mechanism.…”