Ka. Pivnick et al., IDENTIFICATION OF OLFACTORY CUES USED IN HOST-PLANT FINDING BY DIAMONDBACK MOTH, PLUTELLA-XYLOSTELLA (LEPIDOPTERA, PLUTELLIDAE), Journal of chemical ecology, 20(7), 1994, pp. 1407-1427
Olfactory attraction of female diamondback moths (Plutella xylostella)
to odors of intact and homogenized host plants, as well as individual
compounds characteristic of host plants, were investigated by behavio
ral and electrophysiological methods. Moths were attracted to odors of
Brassica juncea and B. napus seedlings in a Y-tube bioassay. Solvent
fractions of homogenized B. juncea leaves were attractive to moths whe
ther or not isothiocyanates (IC) were present. Moths were attracted in
Y-tube bioassays and to field traps baited with individual ICs. Volat
iles from B. juncea and B. napus elicited an electroantennogram (EAG)
response and were attractive in the Y-tube bioassay. Allyl IC was show
n to be the attractive component in homogenized plant volatiles but wa
s found to be virtually absent from intact plant volatiles. Gas chroma
tographic fractionation of intact plant volatiles revealed a terpene-c
ontaining fraction to be most attractive to the moths. We were unable
to isolate individual attractive compounds from this fraction. Our res
ults suggest that certain elements of this fraction, possibly in combi
nation, are important olfactory cues for host-plant finding by the dia
mondback moth with mustard oils playing an important and possibly syne
rgistic role, particularly when plants are damaged.