ABSTRACT
The spotted lanternfly, Lycorma delicatula (White), is an invasive phloem feeder recently introduced into North America that attacks a broad range of woody plants. When feeding in large numbers, they can seriously damage or kill a tree. Their preferred host is the invasive tree-of-heaven, Ailanthus altissima Swingle (Sapindales: Simaroubaceae), but they are serious pests of grape, Vitis vinifera L. (Vitales: Vitaceae) and a number of other commercially important host plants. Volatile collections were conducted on tree-of-heaven and grape, and the most abundant compounds from these plants present in samples and indicated in the literature were tested for attraction in the laboratory and field. Three compounds, methyl salicylate, (Z)-3-hexenol, and (E,E)-α-farnesene, were found to be highly attractive in laboratory behavioral bioassays. Methyl salicylate was attractive to all stages of L. delicatula, whereas the youngest nymphs were not as attracted to (Z)-3-hexenol or (E,E)-α-farnesene in laboratory bioassays. When comparing individual compounds, methyl salicylate attracted the most L. delicatula. Methyl salicylate lures in the field produced a two- to four-fold increase in captures compared with unbaited controls, and field testing also revealed a significant positive dose response. Of the several types of sticky bands tested, Web-Cote Industries sticky bands were found to be most efficient at trapping L. delicatula adults and nymphs.
Subject(s)
Ailanthus , Hemiptera , Animals , North America , Nymph , PheromonesABSTRACT
Three cryptic species in the Euwallacea fornicatus species complex were reared in laboratory colonies and investigated for the presence of pheromones. Collections of volatiles from combinations of diet, fungus, beetles, and galleries from polyphagous shot hole borer (Euwallacea sp. #1) revealed the presence of 2-heneicosanone and 2-tricosanone only in the presence of beetles, regardless of sex. Subsequent examination of volatiles from the other two species, tea shot hole borer (Euwallacea sp. #2) and Kuroshio shot hole borer (Euwallacea sp. #5), revealed these two ketones were present in all three species but in different ratios. In dual choice olfactometer behavioral bioassays, mature mated females were strongly attracted to a synthetic binary blend of ketones matching their own natural ratios. However, females in each species were repelled by ketone blends in ratios corresponding to the other two species. Males of each species responded similarly to females when presented with ratios matching their own or the other two species. The presence of these compounds in the three beetle species, in ratios unique to each species, and their strong species-specific attraction and repellency, suggests they are pheromones. The ecological function of these pheromones is discussed. In addition to the pheromones, the previously known attractant (1S,4R)-p-menth-2-en-1-ol (also known as quercivorol) was discovered in the presence of the fungal symbionts, but not in association with the beetles. Quercivorol was tested in a dual-choice olfactometer and was strongly attractive to all three species. This evidence suggests quercivorol functions as a kairomone for members of the E. fornicatus species complex, likely produced by the symbiotic fungi.
