Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/1999
Publication Date: N/A
Interpretive Summary: Research was conducted that will improve the ability to attract the sap beetle Carpophilus humeralis, in pest management programs. Sap beetles are pests of figs, dates, corn, and other crops in the United States and elsewhere, and new methods of controlling these insects using pheromones have shown great potential. (Pheromones are blends of natural chemicals that insects emit to attract others of their own species.) For Carpophilus humeralis a pheromone is not yet known; however, it was known that this insect is attracted to the pheromone blends of other Carpophilus species. Therefore, the individual components of these pheromone blends and a series of related compounds were tested in the laboratory for the ability to attract C. humeralis. A number of specific compounds were identified as effective, and some of these were attractive at very low doses. This research has defined more exactly the chemicals that will attract a significant agricultural pest, and this information will also be of general interest to pheromone scientists and other entomologists.
Technical Abstract: Carpophilus humeralis (F.) is known from field tests to be more attracted to baits containing the pheromone blends of other Carpophilus species and food odors than to food odors alone, but a pheromone is not yet known for C. humeralis. Wind tunnel tests were used to determine specifically which of the Carpophilus pheromone components were the most attractive for C. humeralis. Nine tetraene and triene components used in the previous field studies, plus eight additional male-specific compounds from other Carpophilus species, and one additional analog were used in these experiments. At the 10-ng level, 15 out of 18 compounds, tested with a food-related coattractant, were significantly more active for C. humeralis than the coattractant alone. As dose levels decreased, the number of significantly active compounds declined. One compound,(2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene (1), had significant attraction at 0.01 ng, close to the lower threshold level of pheromone attraction for other Carpophilus species. Compound 1 was highly synergistic with 4-ethyl-2- methoxyphenol, 2,5-diisopropylpyrazine, and 2-phenylethanol, known C. humeralis attractants. The specificity of C. humeralis for certain tetraenes was similar to that exhibited by C. hemipterus (L.), while the specificity for trienes was similar to that of C. freemani. The behavior of C. humeralis to these components suggests that it may have a pheromone like that of other Carpophilus species or that it may use these compounds as kairomones.