转Bt基因棉对非靶标害虫及害虫天敌种群动态的影响

Effect of transgenic Bt cotton on population dynamics of the non target pests and natural enemies of pests

20 0 0～ 2 0 0 1年 ,在湖北棉区系统研究了转Bt基因棉对棉田非靶标害虫及天敌种群动态的影响。试验设三个处理 :转Bt化防田 (使用化学农药控制害虫 )、转Bt自控田 (仅依靠田间自然天敌控制害虫 )及常规对照棉田 (利用综合防治措施控制害虫 )。结果表明 ,在转Bt基因棉田中 ,除棉蓟马外 ,其它主要非靶标害虫 (主要是刺吸性害虫 )的种群发生数量呈明显的上升趋势。 2 0 0 0年棉蚜发生的总计值 ,化防田和自控田分别比常规对照田增加 37 9%和 71 4% ,2 0 0 1年则分别增加92 5 %和 134 9% ;2 0 0 0年朱砂叶螨发生的总计值 ,化防田和自控田分别比常规对照田增加 181 1%和 2 98 3% ,2 0 0 1年则分别增加 6 9 9%和 10 5 0 % ;转Bt基因棉对于斜纹夜蛾与烟粉虱这两种近几年来对棉花危害有加重趋势的害虫 ,在大田中没有表现出抗性。天敌的发生种类和数量也都远远高于常规对照棉田 ,几种主要天敌种群发生的总计值及高峰值都明显高于常规对照棉田。 2 0 0 0年蜘蛛类发生的总计值 ,化防田和自控田分别比常规对照田增加 6 6 3%和 112 1% ,2 0 0 1年则分别增加 95 1%和 111 7% ;2 0 0 0年龟纹瓢虫发生的总计值 ,化防田和自控田分别比常规对照田增加 140 8%和 135 4% ,2 0 0 1年则分别增加 6 7 2 %和 10 9 5 % ;

Systematic investigations were carried out on the effect of transgenic Bt cotton on the population dynamics of non target pests and natural enemies of pests in Hubei province in 2000-2001.This experiment included three treatments. The first was a transgenic Bt cotton field that utilized pesticides to control pests (FPC), the second was a transgenic Bt cotton field that used natural enemies to control pests (FNEC), and the third was a normal cotton field that adopted IPM (integrated pest management) to control pests (FIPM). The results showed that the population densities of non target pests in transgenic Bt cotton fields were obviously increased. The cumulative and peak numbers of aphids in FPC and FNEC increased by 37 .9% and 71 .4%, respectively, than those recorded in FIPM in 2000 and by 92 .5% and 134 .9% than those recorded in FIPM in 2001. Cumulative and peak numbers of red spider mites in FPC and FNEC increased by 181 .1% and 298 .3%,respectively, than those recorded in FIPM in 2000 and by 69 .9% and 105 .0% than those recorded in FIPM in 2001. Transgenic Bt cotton had no obvious resistance to Prodenia infecta and tobacco whitefly, which have become more serious pests of cotton in recent years. Populations of natural enemies was also significantly higher in transgenic Bt cotton fields. Cumulative and peak values of spiders in FPC and FNEC increased by 66 .3% and 112 .1%,respectively, than those recorded in FIPM in 2000 and by 95 .1% and 111 .7% than those recorded in FIPM in 2001. Cumulative and peak values of Propylaea japonica in FPC and FNEC increased by 140 .8% and 135 .4%,respectively, than those recorded in FIPM in 2000 and by 67 .2% and 109 .5% than those recorded in FIPM in 2001. An important natural enemy in transgenic Bt cotton fields, Geocoris pallidipennis was almost absent in normal cotton fields. These results suggest that optimizing the utilization of natural enemies in transgenic Bt cotton would be a valuable addition to the existing IPM techniques.