AGRICULTURE REPORT - Farmers Can Control Insects By Mixing P

AGRICULTURE REPORT - Farmers Can Control Insects By Mixing Plants
By Bob Bowen

Broadcast: Tuesday, March 29, 2005

I'm Gwen Outen with the VOA Special English Agriculture Report.

Last week, we discussed how farmers can control harmful insects by mixing different kinds of plants with the main crop. But there are also other ways to use plants to protect crops without chemicals. Some plants provide food and protection for insects that help control harmful insects.

Organic Gardening magazine, published by the Rodale Institute, once described some examples, such as ladybugs.

Ladybugs are beetles¹ that like crimson² clover and hairy vetch. They find food, water and a resting place in the clover and vetch. Ladybug larvae³ eat harmful aphids. Aphids are tiny insects that feed on many different kinds of crop plants.

Plants also help each other through their root systems.

For example, scientists say the roots of the marigold flower reduce harmful nematode populations in the soil. Nematodes are tiny worms. There are more than ten-thousand different kinds of nematodes. And some of them feed on corn.

Wild mustard is another plant that releases a poison through its roots. This poison kills nematodes. It also kills some kinds of fungi⁴.

A researcher at the University of California, Santa Cruz, said the wild mustard should be cut close to the ground after the first fifteen days. After that, it should be cut once a month. If left to grow freely, wild mustard will compete with the corn for nutrients⁵ in the soil.

Canadian researchers discovered that the dandelion weed can protect tomato plants from fusarium disease. Fusarium attacks the plant roots. It reduces the number of tomatoes that the plant produces.

Dandelion roots produce cichoric acid. This acid prevents the disease from getting iron from the soil. Fusarium needs iron to survive.

There are, however, plants that should never be grown together. The roots of the black walnut⁶ tree, for example, produce a poison that kills potatoes, peas, tomatoes and peppers.

Dying parts of the brassica family of plants produce a poison that prevents the seeds of some plants from growing. Brassica plants include broccoli⁷, cabbage and cauliflower.

Plants with small seeds, such as lettuce⁸, are especially affected⁹ by the brassica poison. A professor at the University of Connecticut said brassica plants should be removed from the soil after they have produced their crop.

This VOA Special English Agriculture Report was written by Bob Bowen. Internet users can find the first part of our report at www.unsv.com. I'm Gwen Outen.

1 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》

2 crimson   

n./adj.深(绯)红色(的)；vi.脸变绯红色

参考例句：

• She went crimson with embarrassment.她羞得满脸通红。
• Maple leaves have turned crimson.枫叶已经红了。

3 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。

4 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。

5 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

6 walnut   

n.胡桃，胡桃木，胡桃色，茶色

参考例句：

• Walnut is a local specialty here.核桃是此地的土特产。
• The stool comes in several sizes in walnut or mahogany.凳子有几种尺寸，材质分胡桃木和红木两种。

7 broccoli   

n.绿菜花，花椰菜

参考例句：

• She grew all the broccoli plants from seed.这些花椰菜都是她用种子培育出来的。
• They think broccoli is only green and cauliflower is only white.他们认为西兰花只有绿色的，而菜花都是白色的。

8 lettuce   

n.莴苣；生菜

参考例句：

• Get some lettuce and tomatoes so I can make a salad.买些莴苣和西红柿，我好做色拉。
• The lettuce is crisp and cold.莴苣松脆爽口。

9 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。