VOA特别英语在线收听[附英文文本和简单注释] 20040302 |
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AGRICULTURE REPORT - Controlling Fruit Flies in Hawaii
By Mario Ritter
http://language.chinadaily.com.cn/dialogue/voa/special/2004/03/0302.rm
This is Steve Ember with the VOA Special English Agriculture Report.
Fruit flies can damage four-hundred kinds of crops. These insects lay eggs not just in fruit but also vegetables and nuts. The young eat the produce, making it unusable. A female can lay a thousand eggs in her short lifetime.
One of the most destructive kinds of fruit flies is the Mediterranean fruit fly. California, for example, has spent almost thirty years fighting to keep the medfly out of the state.
Even islands far out at sea are not protected. The state of Hawaii has a history of problems with imported pests. The medfly came to Hawaii in the early nineteen-hundreds. Since then, three more kinds of fruit fly pests have arrived.
The Agricultural Research Service of the Department of Agriculture has a team to deal with the problem. The United States Pacific Basin Agricultural Research Center is located in Hilo, Hawaii.
The center has designed a program that aims to keep damage below an economically important level. Lost markets now cost Hawaiian growers an estimated three-hundred-million dollars a year. Roger Vargas is an expert on insects. He started what is called the Hawaii Area-Wide Fruit Fly Integrated Pest Management program. The team says this program is showing success after three years.
Past campaigns tried to kill all the fruit flies. The new program attacks the problem through a series of steps. One is to stop fruit fly reproduction. Infertile male flies are released to mate with the wild population. Also, growers are told to bury all unharvested fruit or vegetables. Or they can place them under a screening structure to keep young flies from escaping.
The program in Hawaii also uses a biological pesticide to kill fruit flies. It is called spinosad. It is produced by a microscopic organism. Spinosad is put into a substance that the fruit flies like to eat. The researchers say this is better for the environment than the common pesticide malathion. Malathion is a chemical that is sprayed on crops.
The program also uses a natural enemy of fruit flies. A kind of wasp called Biosteres arisanus feeds on medflies and oriental fruit flies.
As Kim Kaplan of the Agricultural Research Service reported last month, growers in the program like the results so far. They say they are using less pesticide. And they say they are finding less damaged fruit. Officials have extended the program for two more years.
This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.
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