Identification and Field Testing of Female‐produced Sex Pheromone Components of <i>Dendrolimus suffuscus</i> Subspecies <i>Illustratus</i> De Lajonquière, 1973

The pine caterpillar moth, Dendrolimus suffuscus subspecies Illustratus De Lajonquière, 1973 (Lepidoptera: Lasiocampidae), is the most important defoliator of oriental arborvitae in China. Outbreaks occur over enormous areas and often lead to the death of forests over two to three successive years of defoliation. Using gas chromatography and mass spectrometry, extracts of the female sex pheromone gland of D. suffuscus were found to contain four main chemicals: (Z,E)-5,7-dodecadienal (Z5,E7-12Ald), (Z)-5-dodecenol (Z5-12OH), (Z,E)-5,7-dodecadienyl acetate (Z5,E7-12Ac), and (Z,E)-5,7-dodecadien-1-yl propionate (Z5,E7-12OPr). Electroantennographic (EAG) analyses of these chemicals and their analogs showed that Z5-12Ald and Z5,E7-12Ald elicited the largest male EAG response, followed by Z5-12OH, Z5-12OAc, Z5,E7-12OH, and Z7-12OAc. Field trapping experiments showed that Z5,E7-12Ac were necessary to evoke the attraction of males. The highest number of caught males was achieved when Z5,E7-12Ac, Z5,E7-12Ald, and Z5-12OH were present in baits in the ratio of 5:1:1. Based on our results, the optimal blend of sex pheromone components of D. suffuscus subspecies Illustratus provides the means for detecting and monitoring this population.