AGRICULTURE REPORT - Biocontrols, Part 2

AGRICULTURE REPORT - Biocontrols, Part 2
By Mario Ritter

Broadcast: Tuesday, April 20, 2004

This is Steve Ember with the VOA Special English Agriculture Report.

Biocontrols are the way nature seeks balance. Consider the example of insects that attack crops. Other creatures eat these pests, unless natural controls are missing.

Biocontrols can also include organisms like worms and fungi¹. And they come in the form of bacteria and viruses. These are called pathogens. A good example is a disease that affects Japanese beetles³.

These beetles were accidentally brought to the United States almost one-hundred-years ago. They ate crops and spread out of control.

But in the nineteen-thirties, researchers discovered some young beetles infected with a condition known as milky⁴ disease. The researchers found the bacteria that caused this infection. They put it on the soil for other beetles to eat.

The government used hundreds of tons of the bacteria, called Bacillus popilliae (ba-SI-lus po-PILL-ee-eye). It controlled the Japanese beetles. But today it seems less effective. Another control may be needed.

Plants may also find themselves in a new home where they can reproduce⁵ quickly. The alligator⁶ weed native to South America is one such plant. It came to the United States and took over wetlands and rivers in several states in the South.

In nineteen-sixty-four, researchers released flea⁷ beetles in Florida. Flea beetles are also from South America. They like to eat alligator weed. The beetle² solved the weed problem in central Florida. There was no need for further use of plant poisons. This case serves as a model of biological weed control.

There are three methods for biocontrol. One is conservation. Experts say this is probably the most important. Natural enemies of pests must be protected. This means to avoid treating crops with chemicals that will harm any helpful insects.

A second method is often called classical biological control. This means a helpful biocontrol is released to fight a pest problem. The release of ladybeetles to fight aphids on plants is another such example.

Finally, there is the method of biocontrol that experts call augmentation. Helpful organisms are added to fields to improve environmental balance.

Cornell University in Ithaca, New York, has a full Web site on biocontrol. You can find a link at our site, voaspecialenglish-dot-com. Or enter the words "Cornell" and "biocontrol" into a search engine on the Internet.

This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.

1 fungi   

n.真菌，霉菌

参考例句：

• Students practice to apply the study of genetics to multicellular plants and fungi.学生们练习把基因学应用到多细胞植物和真菌中。
• The lawn was covered with fungi.草地上到处都是蘑菇。

2 beetle   

n.甲虫，近视眼的人

参考例句：

• A firefly is a type of beetle.萤火虫是一种甲虫。
• He saw a shiny green beetle on a leaf.我看见树叶上有一只闪闪发光的绿色甲虫。

3 beetles   

n.甲虫( beetle的名词复数 )

参考例句：

• Beetles bury pellets of dung and lay their eggs within them. 甲壳虫把粪粒埋起来，然后在里面产卵。 来自《简明英汉词典》
• This kind of beetles have hard shell. 这类甲虫有坚硬的外壳。 来自《现代汉英综合大词典》

4 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

5 reproduce   

v.生育，繁殖，复制，重做

参考例句：

• The machine can reproduce a key in two minutes.这机器能在两分钟内复制一把钥匙。
• The picture will reproduce well.这照片会印得很清楚。

6 alligator   

n.短吻鳄(一种鳄鱼)

参考例句：

• She wandered off to play with her toy alligator.她开始玩鳄鱼玩具。
• Alligator skin is five times more costlier than leather.鳄鱼皮比通常的皮革要贵5倍。

7 flea   

n.跳蚤

参考例句：

• I'll put a flea in his ear if he bothers me once more.如果他再来打扰的话，我就要对他不客气了。
• Hunter has an interest in prowling around a flea market.亨特对逛跳蚤市场很感兴趣。