VOA标准英语2008年-Study: Genetically-Engineered Cotton Protects N

According to a study published this week in "Science," genetically¹-engineered cotton planted near conventional crops may help protect the regular plants from bugs². The researchers say the finding could potentially protect a range of crops over millions of hectares. VOA's Jessica Berman reports.
　
Cotton field in Pakistan

The number one threat to cotton crops worldwide is the bollworm, a moth³ whose larvae⁴ feed on the plant's leaves.

Researchers responding to the threat 20 years ago genetically engineered a cotton plant that produces a toxic⁵ protein, called Bacillus thuriniegensis. The protein kills the moth larvae, but is engineered to be safe for humans and animals. Globally, an estimated 14 million hectares of so-called Bt cotton are grown today.

In a study reported this week in Science, researchers report that not only are bollworms destroyed by Bt cotton plants, but the plants appear to benefit unmodified crops that are nearby.

Chinese and American researchers monitored a number of different crops, including peanuts, soybeans, corn and vegetables, between 1992 and 2007 in six provinces in northern China (Hebei, Shandong, Jiangsu, Shanxi, Henan, and Anhui), which covered 38 million hectares of farmland.

Investigators⁶ found that three million hectares of Bt cotton planted among the other crops drove down populations of bollworm pests so much there were fewer moths⁷ to infest⁸ adjacent plants, according to Anthony Shelton an entomologist at Cornell University in Ithaca, New York and an advisor⁹ on the Science paper.

"So, basically what has happened is there has been a regional suppression of the cotton bollworm over a number of different provinces in China because this Bt cotton is acting¹⁰ like a sink and it is a dead end for them," he said.

While the bollworm is primarily a threat to cotton plants, there are lesser¹¹ insect threats to it and surrounding crops.

Some experts, including the authors, have expressed concern that an over reliance on Bt technology has led to a reduction in the use of sprayed pesticides¹² that are effective against a range of insects.

In particular, Shelton notes that mirids, which are leaf eating insects, are becoming a bigger problem in the Bt cotton.

"I do not want to downplay it, but at the same time when things are put into perspective, the benefits for overall pest population suppression of Bt cotton have been tremendous and the mirids are a much smaller player in the pest management program," he said.

There have been other concerns that the bollworm could become resistant¹³ to the toxin¹⁴ produced by Bt cotton. Shelton says that is something to watch out for.

But scientists say the success of Bt cotton in protecting unmodified crops could lead to other Bt crops such as rice.

 

1 genetically   

adv.遗传上

参考例句：

• All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
• Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物

2 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

3 moth   

n.蛾，蛀虫

参考例句：

• A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
• The sweater is moth-eaten.毛衣让蛀虫咬坏了。

4 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

5 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

6 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

7 moths   

n.蛾( moth的名词复数 )

参考例句：

• The moths have eaten holes in my wool coat. 蛀虫将我的羊毛衫蛀蚀了几个小洞。 来自《简明英汉词典》
• The moths tapped and blurred at the window screen. 飞蛾在窗帘上跳来跳去，弄上了许多污点。 来自《现代英汉综合大词典》

8 infest   

v.大批出没于；侵扰；寄生于

参考例句：

• Several animals in sea water can infest wood.海水中有好多动物能侵害木材。
• A lame cat is better than a swift horse when rats infest the palace.宫殿有鼠患，瘸猫比快马强。

9 advisor   

n.顾问，指导老师，劝告者

参考例句：

• They employed me as an advisor.他们聘请我当顾问。
• The professor is engaged as a technical advisor.这位教授被聘请为技术顾问。

10 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

11 lesser   

adj.次要的，较小的；adv.较小地，较少地

参考例句：

• Kept some of the lesser players out.不让那些次要的球员参加联赛。
• She has also been affected,but to a lesser degree.她也受到波及，但程度较轻。

12 pesticides   

n.杀虫剂( pesticide的名词复数 )；除害药物

参考例句：

• vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
• There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》

13 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

14 toxin   

n.毒素，毒质

参考例句：

• Experts have linked this condition to a build-up of toxins in the body.专家已把这一病症与体内毒素的积累联系起来。
• Tests showed increased levels of toxin in shellfish.检验表明水生有壳动物的毒素水平提高了。