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Substantial harm to ecosystems from the use of chemical pesticides has led to an increasing interest in the use of biopesticides to control grasshoppers in rangelands, including China. One such potential biopesticide for control of grasshoppers is the fungus Paranosema locustae. In this study, the dynamics of aboveground natural enemies of grasshoppers and arthropod diversity 0&ndash, 9 years after application of P. locustae were investigated in rangeland in Qinghai Plateau, China. We found that the number of species and of individuals of aboveground natural enemies increased by 17&ndash, 250% and 40&ndash, 126%, respectively, after spraying P. locustae, and that the main natural enemies showed three peaks after treatment. The conventional indices of species diversity (H&rsquo, ) and evenness (J&rsquo, ) increased by 11&ndash, 267% and 13&ndash, 171%, respectively, after treatment with P. locustae. The results showed the positive effects of P. locustae on aboveground natural enemies and biodiversity in an arthropod community in Chinese rangeland. Paranosema locustae is thought to be a safe biological control agent for grasshopper management in Northwestern China.

The aim of this research was to determine chemical composition and repellent and insecticidal activities of the essential oil of Kaempferia galanga L. rhizomes against the booklouse, Liposcelis bostrychophila Badonnel, and to isolate insecticidal or repellent constituents from the oil. The essential oil was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry. Twenty-eight components of the oil were identified. The major compounds in the oil were ethyl-rho-methoxycinnamate (38.6%), ethyl cinnamate (23.2%), 1,8-cineole (11.5%), trans-cinnamaldehyde (5.3%), and borneol (5.2%). Based on bioactivity-guided fractionation, four active constituents were isolated from the oil and identified as 1,8-cineole, ethyl cinnamate, ethyl rho-methoxycinnamate, and trans-cinnamaldehyde. The essential oil exhibited contact toxicity against the booklouse with an LC50 value of 68.6 microg/cm2. Ethyl cinnamate (LC50 = 21.4 microg/cm2) exhibited stronger contact toxicity than ethyl rho-methoxycinnamate and trans-cinnamaldehyde (LC50 = 44.6 and 43.4 microg/cm2, respectively) while 1,8-cineole showed weak acute toxicity. The essential oil also possessed fumigant toxicity against the booklouse with a LC50 value of 1.5 mg/liter air. 1,8-Cineole and trans-cinnamaldehyde (LC50 = 1.1 and 1.3 mg/liter, respectively) possessed stronger fumigant toxicity against the booklouse than ethyl cinnamate and ethyl rho-methoxycinnamate (LC50 = 10.2 and 10.2 mg/liter air, respectively). trans-Cinnamaldehyde was strongly repellent to booklice, whereas ethyl cinnamate and ethyl rho-methoxycinnamate were weakly repellent and 1,8-cineole did not repel booklice. The results indicate that the essential oil and its constituent compounds have potential for development into natural insecticides or fumigants and repellents for control of insects in stored grains.

The aggregation components from fecal volatiles of the oriental migratory locust, Locusta migratoria manilensis were identified with gas chromatographic/electroantennographic detector (GC-EAD), GC-MS (mass spectrometry) analyses and behavioral bioassays. Both last instar nymphs and adults of the oriental migratory locust have similar aggregation pheromones in their volatiles. A total of 11 electrophysiologically active compounds, namely, hexanal, cyclohexanol, heptanal, phenol, 2,5-dimethyl-pyrazine, benzyl alcohol, benzaldehyde, guaiacol, nonanal, 2,6,6-trimethyl-2-cyclohexene-1,4-dione and decyl aldehyde were identified in the fecal volatiles of 2-day-old immature adult male locusts. Only hexanal, nonanal, benzaldehyde, cyclohexanol and 2,5-dimethyl-pyrazine elicited significant aggregation responses in immature 2-day-old adult males. However, adult males had significantly lower behavioral responses to synthetics of five single compounds than the blend of cyclohexanol, 2,5-dimethyl-pyrazine, benzaldehyde, nonanal, hexanal in ratios of 100: 100: 2: 60: 30 in the range of 30–60 μg/mL. We propose that it is the blend of these five compounds that plays a key role in eliciting and sustaining aggregation in gregarious oriental migratory locusts. These results also showed that the aggregation pheromones of the oriental migratory locust are significantly different from those found in the desert locust.