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Title: Behavioral responses of plum curculio (Coleoptera: Curculionidae) to different enantiomer concentrations and blends of the synthetic aggregation pheromone grandisoic acid

Author
item HOCK, VIRGINIA - Institute For Research And Development In Agri-Environment(IRDA)
item CHOUINARD, GERALD - Institute For Research And Development In Agri-Environment(IRDA)
item LUCAS, ERIC - University Of Quebec
item CORMIER, DANIEL - Institute For Research And Development In Agri-Environment(IRDA)
item Leskey, Tracy
item Zhang, Aijun

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2015
Publication Date: 3/15/2015
Citation: Hock, V., Chouinard, G., Lucas, E., Cormier, D., Leskey, T.C., Zhang, A. 2015. Behavioral responses of plum curculio (Coleoptera: Curculionidae) to different enantiomer concentrations and blends of the synthetic aggregation pheromone grandisoic acid. Journal of Economic Entomology. 108(2):549-558.

Interpretive Summary: The plum curculio (PC) is an important native pest of pome and stone fruits, such as apple, plum, peaches, and blueberries, in North American. It is capable of damaging 90% of fruit at harvest. Virgin male PCs produce an aggregation attractant to attract both males and females. However, the synthetic version of the attractant alone did not produce consistent results under field conditions. A series of bioassays were conducted in the laboratory to examine if plant or fruit ordors can synergize the attraction of male-produced attractant. Our results showed that some host plant volatiles can attract and synergize the attraction with the male-produced attractant, depending upon the source (natural/synthetic) of odor used and the physiological state (age/starvation period) of the PC. This study provided usful information to researchers and growers to better understand which host plant volatiles can attract and synergize with the male-produced attractant under what kinds of conditions, which will facilitate development of more efficient tools for PC population monitoring and infestation detection.

Technical Abstract: Host plant odors are important for insect location of food and mates. Synergy between host plant odors and aggregation pheromones occurs in many Curculionidae species. The plum curculio Conotrachelus nenuphar Herbst (Coleoptera: Curculionidae) is a major pest of pome and stone fruit. Males produce the aggregation pheromone grandisoïc acid; attractive to both sexes of the univoltine and multivoltine strains. Grandisoïc acid has one chiral center; the synthetic racemic mixture contains a pair of optical isomers with equal amounts of (+)- and (-)-enantiomers. Males only produce the (+) enantiomer. Synergy between odours can increase trap captures and improve monitoring techniques, but a better understanding of which host plant volatiles attract and synergize with the pheromone and under what conditions is needed. Tests were performed in a dual-choice olfactometer with odours attractive to plum curculios according to literature to determine 1) under what physiological conditions (mating status, age, starvation period) these odours are attractive, 2) if the (+)-enantiomer or the odour of live males synergizes with host plant volatiles, and 3) if there is a difference in response between plum curculio strains. Females were exposed to: benzaldehyde; trans-2-hexanal; apples; extracts of: plums, apples, blueberries; grandisoïc acid; and live males). Results indicate mature females responded the greatest to plum essence, the only attractive synthetic host plant odour; while apples were the only attractive natural plant odour. The physiological state of the insect influenced its response to odours. Plum essence did not synergize with the odour of two males or the (+)-enantiomer grandisoïc acid.