Qi-Yong Weng

Publications (4)0 Total impact

• Article: [Biological activity of capsaicin and its effects on development and fecundity in Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae)].

  Jian-Wei Zhao, Yu Zheng, Yu-Xian He, Qi-Yong Weng
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  ABSTRACT: Biological activity of capsaicin and its effects on development and fecundity in Bemisia tabaci were tested in the laboratory. The results showed that capsaicin induced direct mortality in different developmental stages of B. tabaci, and the mortality of whiteflies were significantly dosage-dependent. The toxicity of capsaicin to different developmental stages of B. tabaci by either leaf-dip or egg/larval-dip bioassays (the LC50 for adult, egg and nymph were 3525.79, 1603.29 and 1526.27 mg x L(-1), respectively) was higher than that by systemic bioassay (the LC50 for adult, egg and nymph were 5360.04, 2359.19 and 5897.43 mg x L(-1), respectively), and toxicity of capsaicin to eggs was higher than to adults in both bioassay methods. 2000 and 4000 mg x L(-1) concentrations of capsaicin had strong antifeedant effect on B. tabaci, as exemplified by reduced honeydew excretion of adults feeding on leaves treated with capsaicin compared with untreated leaf discs. Capsaicin also had strong oviposition deterrence against B. tabaci, with 94. 2% of selective oviposition deterrence rate and 83. 0% of nonselective oviposition deterrence rate when exposed to 4000 mg x L(-1) concentration for 24 h. We did not find effect on development time of B. tabaci eggs and nymphs, and on molting rate of adults when exposed to capsaicin at 500, 1000 and 2000 mg x L(-1) concentrations, however, exposure to 4000 mg x L(-1) concentration of capsaicin significantly affected development time of B. tabaci nymphs and molting rate of adults. Exposure to capsaicin also significantly reduced fecundity of B. tabaci adults, and this reduction was significantly dosage-dependent.
  Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 02/2012; 23(2):531-5.
• Article: [Development of insecticide resistance and its effect factors in field population of Bemisia tabaci in Fujian Province, East China].

  Yu Zheng, Jian-Wei Zhao, Yu-Xian He, Jian Huang, Qi-Yong Weng
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  ABSTRACT: Abstract: The development of insecticide resistance in field populations of Bemisia tabaci from different regions of Fujian Province, China were monitored with adult leaf-dipping bioassay. Compared with bioassay data of 2005, all field populations tested in 2009 still had high levels of resistance to the lambda-cyhalothrin, fenpropathrin and chlorpyrifos, low levels of resistance to methomyl, and no resistance to abamectin. However, resistance to the neonicotinoids imidacloprid and thiamethoxam had increased from moderate levels (23 folds and 25 folds, respectively) in 2005 to high levels (103 folds and 228 folds, respectively) in 2009 in Zhangzhou population, and low levels (1.5-3.3 folds and 1.7-5.5 folds, respectively) in 2005 to moderate levels (23-33 folds and 29-49 folds, respectively) in 2009 for other populations. The biotype of eight B. tabaci populations collected from different regions and hosts were determined according to the mitochondria cytochrome oxidase I (mtCO I ) sequence, and two different biotypes (B-biotype and indigenous whitefly) were detected. The samples collected from geographical regions and hosts showed a prevalence of the B-biotype, and indigenous whitefly (unknown biotype) existed only in croton of Zhangzhou. Host plants and temperature had limited effects on insecticide development in B. tabaci, while extensive and high frequent use of neonicotinoids could be the most important factors responsible for rapid development of insecticide resistance in field populations of B-biotype B. tabaci.
  Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 01/2012; 23(1):271-7.
• Article: [Effects of host plants on selection behavior and biological parameters of Bemisia tabaci Gennadius biotype B].

  Jian-wei Zhao, Yu-xian He, Qi-yong Weng, Dong-dong Wu
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  ABSTRACT: Based on the observation of free diffusion in petri dish and biology, the selection behavior and biological parameters of Bemisia tabaci Gennadius biotype B on host plants cucumber, eggplant, pepper, cotton, and sweet potato were investigated. No difference was observed in the individual number of B. tabaci on the five host plant leaves during the early period of free diffusion (within 2 h), but changes were found within the following periods (4-48 h), i.e., the B. tabaci individuals increased on cucumber, decreased on pepper, and were relatively stable on eggplant, cotton, and sweet potato, which indicated that there were significant differences in the selectivity of B. tabaci on the five host plants, with the highest selectivity to cucumber and the lowest selectivity to pepper. Pretreatment by starvation and imidacloprid did not affect the selectivity of B. tabaci. There were significant differences on the honeydew excretion of female B. tabaci adults on the host plants, which was in the order of cucumber > sweet potato > cotton > eggplant > pepper. The average longevity of B. tabaci adults on cucumber, eggplant, sweet potato, and cotton was significantly longer than that on pepper, and the total number of eggs laid per female on cucumber, eggplant, sweet potato, and cotton (224.33, 182.33, 191.73, and 172.60 respectively) was significantly larger than that on pepper (only 47.83). No significant differences were observed in the hatching rate and development period of the eggs on the five host plants. The development period of nymphs on cucumber, eggplant, sweet potato, and cotton was 10.60 d, 11.96 d, 11.11 d, and 13.20 d, and the mortality was 5.21%, 27.78%, 17.24%, and 37.11%, respectively. The nymphs failed to develop normally on pepper.
  Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 09/2009; 20(9):2249-54.
• Article: [Insecticide resistance of Bemisia tabaci field populations].

  Yu-Xian He, Qi-Yong Weng, Jian Huang, Zhi-Sheng Liang, Gui-Jun Lin, Dong-Dong Wu
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  ABSTRACT: Resistance to 13 insecticides in field populations of Bemisia tabaci from six regions (Fuzhou, Zhangzhou, Longyan, Sanming, Nanping, Ningde) of Fujian Province, China was monitored by adult leaf-dipping bioassay. Compared with the susceptible SUD-S strain, all the six field populations exhibited high levels of resistance to lambda-cyhalothrin (838.38-2460.52 fold), fenpropathrin (244.64-834.29 fold), cypermethrin (116.02-266.35 fold), deltamethrin (81.75-124.18 fold), acephate (425.18-875.56 fold) and chlorpyrifos (54.53-78.43 fold), moderate levels of resistance to dimethoate (14.16-17.66 fold), low to moderate levels of resistance to dichlorvos (6.23-11.25 fold) and low levels of resistance to methomyl (4.07-5.66 fold), respectively. Among these six field-collected populations, only Zhangzhou population had moderate resistance to imidacloprid, acetamiprid and thiamethoxam (23.08 fold, 10.32 fold and 24.60 fold, respectively). All field strains tested displayed no resistance to abamectin.
  Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 08/2007; 18(7):1578-82.