Electrophysiological and Behavioral Responses of Chrysopa phyllochroma (Neuroptera: Chrysopidae) to Plant Volatiles.

The lacewing Chrysopa phyllochroma Waesmael is a polyphagous predator of many pests. Releasing lacewings is an important component of biological control programs, but it is difficult to establish populations on field crops. Electrophysiological and behavioral responses to 10 common plant volatiles were recorded to screen for lacewing-attracting compounds. Electroantennographic assays indicated that all of the tested compounds elicited responses from C. phyllochroma. Three green-leaf volatiles-(E)-2-hexenal, (Z)-3-hexenyl acetate, and (Z)-3-hexenol-produced the strongest responses. Weaker responses were observed to six terpenes-ocimene, linalool, (3E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-α-farnesene, limonene, and nerolidol-and to methyl salicylate. Using a Y-tube olfactometer, the behavioral assays of the eight most active compounds demonstrated that four-(Z)-3-hexenyl acetate, (Z)-3-hexenol, (3E)-4,8-dimethyl-1,3,7-nonatriene, and linalool-were significant attractants for C. phyllochroma at specific concentrations. Three common plant volatile compounds-(Z)-3-hexenyl acetate, (3E)-4,8-dimethyl-1,3,7-nonatriene, and linalool-were also found to significantly enhance female ovipositing, resulting in a concentration of eggs. These observations are important for lacewing release as a pest control measure because they suggest means for retaining individuals and establishing populations using common plant volatiles.