At least 1,200 tons of insecticide, 50,000 spraying machines and
four crop-dusting aircraft have been mobilized to control locusts
swarming over an estimated 800,000 hectares across northern China,
the Ministry of Agriculture said yesterday.
Ministry official Zhu Enlin said that biological pesticides
account for 10 percent of the total being sprayed in nine provinces
and municipalities this year in the belief that they will have less
of a negative impact on the environment.
Funds earmarked for efforts total 12 million yuan (US$1.4
million), said Zhu, adding "Migratory locusts are not occurring as
massively as they did last year and may not pose great harm to
crops."
However, efforts to control them are necessary to prevent swarms
continuing into the autumn, even though the current insect
population is not itself a threat, he added.
According to experts, the locusts' usual habitat is dry
wasteland near rivers, lakes and reservoirs, but if their
population density is too high they migrate to open land in search
of food.
Their density is 5-20 per square meter at present, compared with
thousands per square meter last year, according to the Ministry of
Agriculture.
The comparatively light density this year is largely a result of
last year's effective control measures and heavier rainfall earlier
this year, said Zhu.
In an interview yesterday, Lei Zhongren, a Chinese Academy of
Agricultural Sciences researcher, said migratory locusts and
grasshoppers, cause losses of 60 to 100 million kilograms of grain
each year.
Lei said biological pesticides using the fungus Metarhizium
flavoviride are increasingly being used as they target the locusts
without damaging other species or affecting the overall food chain,
unlike chemical pesticides.
(China Daily June 28, 2005)