Search

Background: The Chinese pine caterpillar moth, Dendrolimus tabulaeformis Tsai and Liu (Lepidoptera: Lasiocampidae) is the most important defoliator of coniferous trees in northern China. Outbreaks occur over enormous areas and often lead to the death of forests during 2-3 successive years of defoliation. The sex pheromone of D. tabulaeformis was investigated to define its chemistry and behavioral activity. Methodology/Principal Findings: Sex pheromone was collected from calling female D. tabulaeformis by headspace solid phase microextraction (SPME) and by solvent extraction of pheromone glands. Extracts were analyzed by coupled gas chromatography/mass spectrometry (GC-MS) and coupled GC-electroantennographic detection (GC-EAD), using antennae from male moths. Five components from the extracts elicited antennal responses. These compounds were identified by a combination of retention indices, electron impact mass spectral matches, and derivatization as (Z)-5-dodecenyl acetate (Z5- 12:OAc), (Z)-5-dodecenyl alcohol (Z5-12:OH), (5Z,7E)-5,7-dodecadien-1-yl acetate (Z5,E7-12:OAc), (5Z,7E)-5,7-dodecadien-1-yl propionate (Z5,E7-12:OPr), and (5Z,7E)-5,7-dodecadien-1-ol (Z5,E7-12:OH). Behavioral assays showed that male D. tabulaeformis strongly discriminated against incomplete and aberrant blend ratios. The correct ratio of Z5,E7-12:OAc, Z5,E7-12:OH, and Z5,E7-12:OPr was essential for optimal upwind flight and source contact. The two monoenes, Z5-12:OAc and Z5-12:OH, alone or binary mixtures, had no effect on behavioral responses when added to the optimal threecomponent blend. Conclusions/Significance: The fact that deviations from the optimal ratio of 100:100:4.5 of Z5,E7-12:OAc, Z5,EZ7-12:OH, and Z5,E7-12:OPr resulted in marked decreases in male responses suggests that biosynthesis of the pheromone components is precisely controlled. The optimal blend of the sex pheromone components of D. tabulaeformis worked out in this study should find immediate use in monitoring this pest in Chinese forests. [ABSTRACT FROM AUTHOR]

The pine caterpillar moth, Dendrolimus kikuchii Matsumura (Lepidoptera: Lasiocampidae), is a pest of economic importance on pine in southwest China. Three active compounds were detected during analyses of solvent extracts and effluvia sampled by solid phase microextraction (SPME) from virgin female D. kikuchii using gas chromatography (GC) coupled with electroantennographic (EAG) recording with antennae from a male moth. The compounds were identified as (5 Z,7 E)-5,7-dodecadien-1-yl acetate ( Z5, E7-12:OAc), (5 Z,7 E)-5,7-dodecadien-1-ol ( Z5, E7-12:OH), and (5 Z)-5-dodecenyl acetate ( Z5-12:OAc) by comparison of their GC retention indices, mass spectra, and EAG activities with those of synthetic standards. Microchemical reactions of gland extracts provided further information confirming the identifications of the three components. Solvent extractions and SPME samples of pheromone effluvia from virgin calling females provided 100:18:0.6 and 100:7:1 ratios of Z5, E7-12:OAc: Z5, E7-12:OH: Z5-12:OAc, respectively. Field behavioral assays showed that Z5, E7-12:OAc and Z5, E7-12:OH were essential for attraction of male D. kikuchii moths. However, the most attractive blend contained these three components in a 100:20:25 ratio in a gray rubber septa. Our results demonstrated that the blend of Z5, E7-12:OAc, Z5, E7-12:OH, and Z5-12:OAc comprise the sex pheromone of D. kikuchii. The optimized three-component lure blend is recommended for monitoring D. kikuchii infestations. [ABSTRACT FROM AUTHOR]

The larch caterpillar moth, Dendrolimus superans Butler (Lepidoptera: Lasiocampidae), is a serious pest in the northeastern part of China. In order to develop an effective method for monitoring D. superans, we began a project to identify the sex pheromone of D. superans and preliminary results were published in a note in 2001. Here we report complete laboratory and field results to support the identification. ( Z, E)-5,7-Dodecadienal, ( Z, E)-5,7-dodecadienol, ( Z)-5-dodecenol, and ( Z)-5-dodecenal (100:95:75:71) were identified by gas chromatography (GC) and coupled GC-mass spectrometry in extracts of pheromone glands of female D. superans. However, only ( Z, E)-5,7-dodecadienal elicited strong responses from conspecific male antennae in coupled GC-electroantennography studies. Field tests with synthetic compounds indicated that baits containing ( Z, E)-5,7-dodecadienal as a single component attracted male D. superans moths, whereas addition of one, two, or all three of the possible minor components did not increase the attractiveness of lures. ( Z, E)-5,7-Dodecadienyl acetate, one of the pheromone components in sympatric Dendrolimus species, was antagonistic, but the analog ( Z, E)-5,7-dodecadienyl propionate, another pheromone component in sympatric Dendrolimus species, was not. Since 2005, pheromone traps baited with ( Z, E)-5,7-dodecadienal have been used effectively for monitoring populations of D. superans in various areas of northeastern China. [ABSTRACT FROM AUTHOR]