时间:2019-01-30 作者:英语课 分类:农业与发展


英语课

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 fungi 1. And they come in the form of bacteria and viruses. These are called pathogens. A good example is a disease that affects Japanese beetles 3.


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 milky 4 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 reproduce 5 quickly. The alligator 6 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 flea 7 beetles in Florida. Flea beetles are also from South America. They like to eat alligator weed. The beetle 2 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.



n.真菌,霉菌
  • 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。
n.甲虫,近视眼的人
  • 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。
n.甲虫( beetle的名词复数 )
  • 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》
adj.牛奶的,多奶的;乳白色的
  • 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。
v.生育,繁殖,复制,重做
  • 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。
n.短吻鳄(一种鳄鱼)
  • 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。
n.跳蚤
  • 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。
学英语单词
-spermal
Aberargie
activating
aquatic organisms index
Brazil wax
cattle weighing unit
caverly
cavincidine
Cawley
chidlhood rheumatoid disease
cinetography
compressed speech
crown root
cutting down capital construction scale
cystoscopic lithotrite
detwinning
ditcher
drunkards
dual fuel nozzle
E-6A
eats into
ecky
endiablement
europress
exophylaxis
file of index access
file-type virus
formal push-down automaton
frigorifico
Gwytherin
gypsyings
Hampden Row
heated water discharge
hire oneself out
home-appliance
hsmp
iizuka
infusion in seam
innater
inter arma silent leges
intra-modal dispersion
iron(ii) oxalate
isopropyl-urea
Jacobi-Gauss quadrature
Jastrowie
jaw-winking phenomenon
key transformation
langoustine
leakage flow(rate)
lone-pairs
louffe
maca root
management of log transportation
masked hunters
Mclndoe
Mekongga, Gunung
metal diaphragm
micrococcus pemphigi neonatorium
multisage satellite
nervi splanchnici pelvici
neutral spectrometer
nonimitations
notarisation
oileries
oosperm
P.O. (power output)
Padangsidìmpuan
photographers
Pole
preparation service
primary rectifier
pudd
pudendal plexus
puseys
regeneratine capacity
reuter's index
roll knobbing
rutleys
securinol
selection addressing
semilunar membrane
Shortbill
single planetary gear train
slight pitch
ST_doing-and-achieving_taking-part-and-getting-involved
steeping and pressing tank
surface bargaining
surplus load
The die is cast
tongue and groove with bead joint
transverse muscle of abdomen
tring
trumeau
type families
UGPTBD
under-compounded DC machine
uniform mixture
United Engineers & Constructors Incorporated
ureteral fistula
well record
woodchopping
zhenqi fuzheng granules