Influence of Trap Color and San Jose Scale (Homoptera: Diaspididae) Pheromone on Sticky Trap Catches of 10 Aphelinid Parasitoids (Hymenoptera)

Abstract

The influence of trap color and a combination of trap color plus San Jose scale, Quadraspidiotus perniciosus (Comstock), sex pheromone on sticky trap catches of aphelinid parasitoids of the San Jose scale was studied in an unsprayed apple orchard in Johnston County, N.C., in 1986 and 1987, and a sprayed commercial peach orchard in Nash County, N.C., in 1987. The responses of parasitoids to five enamel paints were compared in 1986, and similar responses to three enamel paints with and without the San Jose scale pheromone were compared in 1987. The adult parasitoids (3,958 total) collected on the traps represented ten aphelinid species: Ablerus clisiocampae (Ashmead), Aphytis diaspidis (Howard), Encarsia sp., A. melanostictus Compere, Coccobius sp., Coccophagoides murtfeldtae (Howard), E. aurantii (Howard), E. perniciosi (Tower), Marietta carnesi (Howard), and M. mexicana (Howard). Black traps attracted significantly more C. murtfeldtae and Encarsia sp. (endoparasitic species) than did other colors, suggesting a response to the contrast between the bark and foliage of the tree. Yellow and black traps attracted significantly more A. diaspidis , an ectoparasitic species, than white traps at both orchards in 1987. Colored traps baited with San Jose scale pheromone attracted significantly more E. perniciosi , an endoparasitic species, than colored traps without San Jose scale pheromone. This indicates that San Jose scale pheromone is a kairomone for the parasitoid. In comparisons with colored traps baited with pheromone, black traps attracted significantly more E. perniciosi than did yellow or white traps in the unsprayed apple orchard in 1987. This suggests an interaction between olfactory and visual cues in host location by this species.