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BT转基因棉花成为盲椿病虫害来源

所属:听力板块 阅读:2313 次 评论:0 条 [我要评论]  [+我要收藏]

小编摘要:2008年,科学家就中国北方6省棉花种植的一项研究发表报告。这项研究涉及到棉农的一个主要威胁:棉铃虫。同时还涉及到Bt棉花,一种能够抵制此类威胁的转基因棉花。

A Cotton Plant Kills One Kind of Bug, but Gets Blamed for Another

Photo: AP
A worker carries raw cotton in the city of Korla in northwest China's Xinjiang Uygur Autonomous Region

In two thousand eight, scientists reported on a study of cotton grown in six provinces in northern China. The study involved bollworms, a major threat to cotton farmers. It also involved Bt cotton, a plant genetically engineered to resist that threat.

Bt cotton plants naturally kill bollworms. As a result, the study in China found that the cotton plants could also help protect nearby crops against damage by the insects.

Now, several researchers involved in that study have published another report in the same journal, Science. They studied the same farmlands again and confirmed the findings about bollworms.

But they also found something else. They say another kind of bug is now attacking the cotton and other crops.

The study reported on mirid populations between nineteen ninety-seven and two thousand eight. The researchers also documented the use of insecticide chemicals by the Chinese farmers from nineteen ninety-two to two thousand eight.

Kongming Wu of the Chinese Academy of Agricultural Sciences in Beijing took part in both studies. He says mirids are destroying crops including cotton, apples, pears, peaches and vegetables. He says this is happening where mirids never before were a problem.

The report says the bugs invaded after farmers decreased their use of insecticides by planting Bt cotton. The scientists say their research shows that the Bt cotton has become a source of mirids. They say the population increases are related to drops in insecticide use on the cotton crop.

The genetically engineered cotton is designed to help farmers save money by decreasing the need for poisons. But the scientists say the Chinese farmers have now had to use more insecticides to fight the mirids.

Bt is a bacterium that was discovered in the early twentieth century. Farmers started using it as a natural way to kill insects. Then scientists learned how to put a Bt gene into cotton plants.

Much of the cotton grown in northern China is a Bt variety made by Monsanto. Different companies produce Bt cotton. Around the world, farmers grow an estimated sixteen million hectares of Bt cotton.

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2012-07-01 22:28 编辑:pliny
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