Browsing by Author "Ge, F"

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Development and Reproduction of Propylaea Japonica (Coleoptera: Coccinellidae) Raised on Aphis Gossypii (Homoptera: Aphididae) Fed Transgenic Cotton
(Biodiversity Research Center, Acad Sinica, 2006) Zhu, SR; Su, JW; Liu, XH; Du, L; Yardim, EN; Ge, F
Development and reproduction of Propylaea japonica (Coleoptera: Coccinellidae) raised on Aphis gossypii (Homoptera: Aphididae) fed transgenic cotton. Zoological Studies 45(1): 98-103. A laboratory experiment was designed to evaluate the effects of transgenic cotton containing Bacillus thuringiensis (Berliner) Cry1Ac toxin on the survival, development, and fecundity of a predatory ladybeetle, Propylaea japonica (Thunberg), through a food chain using cotton aphid, Aphis gossypii Glover as an herbivorous prey. No significant differences were observed in total survival from hatching to adult, or in larval and pupal durations of P. japonica supplied with aphids fed on either transgenic or non-transgenic cotton. Similarly, no significant differences in longevity, reproduction, weight, or fatty acid contents of adult beetles were detected. Our results suggest that this type of transgenic cotton might have little effect on the survival, development, and fecundity of P. japonica through this food chain.
The Effect of Low Temperatures on Diapause and Non-Diapause Larvae of the Pine Caterpillar, Dendrolimus Tabulaeformis Tsai Et Liu (Lepidoptera:lasiocampidae)
(Springer Japan Kk, 2005) Han, R; Ge, F; Yardim, EN; He, Z
Some effects of low temperatures on diapause and non-diapause larvae of the pine caterpillar, Dendrolimus tabulaeformis Tsai et Liu (Lepidoptera: Lasiocampidae), were investigated in laboratory experiments. The results indicated that diapause larvae had higher survival rates than non-diapause larvae at earlier stages of exposure to the low temperatures (-10, -17 and -21 degrees C). In general, the larvae lives were shorter when they were exposed to the lower temperatures. Exposure to chilling at 0 degrees C (cold pulse) in advance increased the survival rate of larvae when they were exposed to -10 degrees C, and the survival rate increased with the length of cold pulse (doubled at 50 min). No larvae could survive after the 50th day of daily exposure to -10 degrees C for 1 h followed by exposure to 27 +/- 1 degrees C for 23 h. The water contents of diapause and non-diapause larvae differed significantly, and the super-cooling points (SCPs) of non-diapause larvae were significantly higher than those of diapause larvae.
Evaluation of Winter Wheat as a Potential Relay Crop for Enhancing Biological Control of Cotton Aphids in Seedling Cotton
(Springer, 2004) Men, XY; Ge, F; Yardim, EN; Parajulee, MN
A 2-year study was conducted to evaluate the role of winter wheat, Triticum aestivum L., as a potential relay crop to conserve arthropod natural enemies and suppress cotton aphids, Aphis gossypii Glover, in seedling cotton. The results suggested that the natural enemies that moved from the adjacent wheat fields to cotton fields with the maturity and harvest of wheat could keep the cotton aphid population at the edges (0-4 m) of cotton fields under the action threshold of 100 aphidS/m(2). Data also suggested that the wheat strip served as a reservoir to conserve arthropod predators and "relayed" its predators to cotton when wheat matured and senesced.
The Influence of Pesticide Applications on Helicoverpa Armigera Hubner and Sucking Pests in Transgenic Bt Cotton and Non-Transgenic Cotton in China
(Elsevier Sci Ltd, 2005) Men, X; Ge, F; Edwards, CA; Yardim, EN
Effects of pesticide applications, based on an IPM program on cotton bollworm, Helicoverpa armigera Hubner, cotton mirids and cotton leafhoppers, were evaluated in transgenic Bt-cotton and non-transgenic cotton agroecosystems between 1999 and 2001 in China. Differences in pest populations between cotton varieties were also compared. In 1999 and 2000, bollworm populations on non-transgenic cotton were larger than those on transgenic Bt-cotton. In Bt-cotton fields, the numbers of fourth-generation bollworms were greater than those of in the second and the third generations over all 3 years of study. Leafhopper populations on Bt-cotton were consistently larger than those on non-transgenic cotton during the 3 years of study. Although the use of transgenic Bt-cotton decreased the need for insecticide applications against cotton bollworm, this relaxation from pesticide applications could cause increased populations of sucking insects, which could require additional insecticide applications. (C) 2004 Elsevier Ltd. All rights reserved.
Influence of Pesticide Applications on Pest and Predatory Arthropods Associated With Transgenic Bt Cotton and Nontransgenic Cotton Plants
(Springer, 2004) Men, XY; Ge, F; Edwards, CA; Yardim, EN
The effects of pesticide applications on pests (aphids and acarid mites) and predators (ladybeetles and spiders) were investigated in transgenic Bt cotton and nontransgenic cotton agroecosystems in 1999, 2000 and 2001. Transgenic cotton did not cause changes in populations of acarids and did not reduce numbers of predators considerably; its effects on aphids were inconsistent. Although insecticides were not applied against the main pest cotton bollworm - on transgenic cotton, the total number of insecticide applications in 3 years was no less than the total applied on nontransgenic cotton, because additional applications were required against sucking pests on transgenic Bt cotton. Pesticide applications decreased numbers of aphids, acarids and predatory spiders significantly on both transgenic and nontransgenic cottons. The results suggest that the use of Bt cotton should be evaluated carefully in China.
Quantification of Diapausing Fourth Generation and Suicidal Fifth Generation Cotton Bollworm, Helicoverpa Armigera, in Cotton and Corn in Northern China
(Blackwell Publishing, 2005) Ge, F; Chen, F; Parajulee, MN; Yardim, EN
Cotton bollworm, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), is a major pest of cotton and corn crops in northern China. A phenological differentiation between fourth generation cotton bollworms from cotton and those from corn fields was observed in northern China during 1999-2000. The proportion of pupation in late fall was marginally higher in cotton fields compared to that in corn fields; however, the proportions of fall emergence of moths from cotton fields were significantly higher than those from corn fields. The proportion of spring emergence of moths was also significantly higher for larvae collected from cotton (28.0%) than from corn (14.5%). The overwintering duration of females was significantly shorter than that of males in both crops. Moreover, the overwintering duration of bollworm populations from cotton was significantly longer than that from corn. The early spring population of H. armigera came from both cotton and corn fields, but the spring emergence of moths from larvae collected from cotton took about 5 days longer to reach 100% emergence compared to that from corn.