Resistance of five field populations of Mythimna separata（Walker） collected from Shaanxi and Shanxi provinces of China to six different insecticides was evaluated by leaf dip method in the laboratory. The results sh...Resistance of five field populations of Mythimna separata（Walker） collected from Shaanxi and Shanxi provinces of China to six different insecticides was evaluated by leaf dip method in the laboratory. The results showed that all populations were relatively sensitive to emamectin benzoate with a resistance ratio（RR） of 0.583–1.583 folds. All populations showed susceptible or low level resistance to chlorantraniliprole and beta-cypermethrin. Compared with a relatively susceptible strain of M. separata, the resistance level of the whole populations ranged from susceptible to moderate to chlorpyrifos and lambda-cyhalothrin, moderate to high to phoxim（RR=19.367–70.100） except for population from Sanyuan County（RR=2.567）. Pair-wise correlation analysis among different insecticides indicated that chlorpyrifos has a significantly positive and significant correlation with emamectin benzoate. Chlorantraniliprole didn＇t have significant correlation with emamectin benzoate, chlorpyrifos and phoxim. Therefore, emamectin benzoate, chlorantraniliprole and beta-cypermethrin are recommended to control oriental armyworm. Meanwhile, to postpone the occurrence and development of insecticide resistance in Shaanxi and Shanxi provinces, alternative and rotational application of insecticides between chlorantraniliprole and emamectin benzoate or chlorpyrifos is necessary.展开更多
Effects of cycling and constant temperature on development and reproduction of the armyworm, Mythimna separata (Walker) were investigated by rearing the insects on the artificial diet under temperatures covering low(1...Effects of cycling and constant temperature on development and reproduction of the armyworm, Mythimna separata (Walker) were investigated by rearing the insects on the artificial diet under temperatures covering low(16-24℃ vs. 20 ℃ ), medial(20-28℃ vs. 24℃ ) and high(24-32 ℃ vs. 28 ℃) regions. In the low region, all the immature stages of the insect developed significantly faster under alternating temperatures than at corresponding constant temperatures. For the medial region, their development was little affected by variable temperatures. For the high region, developmental durations tended to be longer under cycling temperatures except egg stage.Mean fecundities of the adult moths markedly increased under cycling temperatures as compared with those at respective constant temperature in all regions.Possible reasons for effect of alternating temperatures on insect development are discussed in some details.展开更多
The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much...The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much of the uniquely difficult aspects of managing M.separata arises from its long-distance migratory behavior.For example,direction and timing of winds from its overwintering regions in the south largely determine where and when large influxes of migrants arrive in the north to oviposit,making prediction of infestations difficult.展开更多
Fraxinellone, a naturally occurring degraded limonoid, is mainly isolated from Dictamnus dasycarpus and Melia azedarach. In continuation of our program aimed at the discovery of plant natural products-based insecticid...Fraxinellone, a naturally occurring degraded limonoid, is mainly isolated from Dictamnus dasycarpus and Melia azedarach. In continuation of our program aimed at the discovery of plant natural products-based insecticidal agents, twenty-two new ethers from furyl-ring-based acylation derivatives were prepared by structural modifications of fraxinellone. Their insecticidal activity was evaluated against the pre-thirdinstar larvae of Mythimna separata Walker in vivo. Among them, compounds 5 e and 5 j exhibited more potent insecticidal activity than toosendanin with the final mortality rates greater than 60%. Their structure-activity relationships were also discussed.展开更多
基金supported by the Special Fund for Agroscientific Research in the Public Interest of China (201403031)the Research Project Program of Agricultural Science and Technology innovation Transformation in Shaanxi Province, China
文摘Resistance of five field populations of Mythimna separata（Walker） collected from Shaanxi and Shanxi provinces of China to six different insecticides was evaluated by leaf dip method in the laboratory. The results showed that all populations were relatively sensitive to emamectin benzoate with a resistance ratio（RR） of 0.583–1.583 folds. All populations showed susceptible or low level resistance to chlorantraniliprole and beta-cypermethrin. Compared with a relatively susceptible strain of M. separata, the resistance level of the whole populations ranged from susceptible to moderate to chlorpyrifos and lambda-cyhalothrin, moderate to high to phoxim（RR=19.367–70.100） except for population from Sanyuan County（RR=2.567）. Pair-wise correlation analysis among different insecticides indicated that chlorpyrifos has a significantly positive and significant correlation with emamectin benzoate. Chlorantraniliprole didn＇t have significant correlation with emamectin benzoate, chlorpyrifos and phoxim. Therefore, emamectin benzoate, chlorantraniliprole and beta-cypermethrin are recommended to control oriental armyworm. Meanwhile, to postpone the occurrence and development of insecticide resistance in Shaanxi and Shanxi provinces, alternative and rotational application of insecticides between chlorantraniliprole and emamectin benzoate or chlorpyrifos is necessary.
文摘Effects of cycling and constant temperature on development and reproduction of the armyworm, Mythimna separata (Walker) were investigated by rearing the insects on the artificial diet under temperatures covering low(16-24℃ vs. 20 ℃ ), medial(20-28℃ vs. 24℃ ) and high(24-32 ℃ vs. 28 ℃) regions. In the low region, all the immature stages of the insect developed significantly faster under alternating temperatures than at corresponding constant temperatures. For the medial region, their development was little affected by variable temperatures. For the high region, developmental durations tended to be longer under cycling temperatures except egg stage.Mean fecundities of the adult moths markedly increased under cycling temperatures as compared with those at respective constant temperature in all regions.Possible reasons for effect of alternating temperatures on insect development are discussed in some details.
基金the special fund for Agro-scientific Research in the Public Interest of China(201403031)for support of this special focus
文摘The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much of the uniquely difficult aspects of managing M.separata arises from its long-distance migratory behavior.For example,direction and timing of winds from its overwintering regions in the south largely determine where and when large influxes of migrants arrive in the north to oviposit,making prediction of infestations difficult.
基金supported by the National Natural Science Foundation of China (No. 31672071)Special Funds of Central Colleges Basic Scientific Research Operating Expenses (No. 2452015096)
文摘Fraxinellone, a naturally occurring degraded limonoid, is mainly isolated from Dictamnus dasycarpus and Melia azedarach. In continuation of our program aimed at the discovery of plant natural products-based insecticidal agents, twenty-two new ethers from furyl-ring-based acylation derivatives were prepared by structural modifications of fraxinellone. Their insecticidal activity was evaluated against the pre-thirdinstar larvae of Mythimna separata Walker in vivo. Among them, compounds 5 e and 5 j exhibited more potent insecticidal activity than toosendanin with the final mortality rates greater than 60%. Their structure-activity relationships were also discussed.
