Beijing, China
January 11, 2006
by Jia Hepeng and Wu Chong,
SciDev.Net
Chinese scientists have developed a way to protect crops using
wasps that deliver lethal viruses to insect pests.
The technique, developed at the
Wuhan Virus
Research Institute won second prize at the 2005 National
Technological Invention Awards, which were presented at the
National Science and Technology Congress in
Beijing on Monday (9 January).
Lead researcher Peng Huiyin says the approach costs 25-40 per
cent less than chemical pesticides and is more environmentally
friendly. It can control more than 20 insect pests, mainly
caterpillars, he adds.
Both viruses and parasitic wasps have been used to kill pests
before, but the Chinese scientists are the first to combine the
tactics, says co-researcher Zhang Lin.
Certain parasitic wasps lay their eggs in those of other
insects. The wasp larvae feed there, killing their hosts before
hatching.
The researchers took parasitised insect eggs and soaked them in
a solution containing a virus that is lethal to the pest, but
harmless to the wasp. When the wasps' offspring hatched, the
virus became attached to their bodies.
The idea was to exploit the fact that females often crawl over
hundreds of pest eggs before selecting one to lay their egg in.
"This way the virus can be spread to hundreds of pest eggs,"
Zhang told SciDev.Net.
After hatching, any pest larvae that have not been parasitised
feed on the remains of their eggs and ingest the lethal virus.
Zhang says that during 15 years of research, the team has
identified more than 20 viruses that kill different pests but
not the wasp.
Field trials of the methods have been conducted on more than
13,000 hectares of farmland in China. "It is very likely to be
commercialised within one or two years," says Zhang.
Farmers using the method would put virus-coated pest eggs that
contain developing wasps in their fields and wait for the wasps
to emerge. Depending on which pest was a problem, wasps could be
tailored to carry a different virus.
The researchers have published most of their findings to date in
the journal Virus Research, with their most recent paper
appearing in last month's edition.
So
far, there is no evidence that the pest species have developed
resistance to the viruses, says Zhang.
Reference:
Virus Research 114, 80 (2005)
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Related links:
Wuhan Virus Research Institute (English)
Wuhan Virus Research Institute (Chinese) |