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| Tuesday,
2 December, 2003 |
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| SCIENTISTS
USE BIOLOGICAL WEAPONS IN BATTLE AGAINST ARMYWORM CATERPILLAR CROP-WRECKERS |
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The caterpillar appears in plague proportions across eastern and southern Africa, where the only form of control is to use expensive and environmentally damaging insecticides. But now researchers are using a devastating insect virus, which occurs naturally in armyworms, to safely and effectively control these vast armies of caterpillars that range over tens of thousands of hectares, voraciously feeding on pasture and crops. This virus, called NPV (nucleopolyhedrovirus), can kill 98% of armyworm caterpillars and is specific to this species. It is completely safe for humans, other animals and even other insects. But for NPV to be effective it needs a helping hand from science, because when left to nature the virus usually spreads too slowly to prevent plagues of the insects damaging crops. So scientists have artificially produced and sprayed the virus onto early outbreaks of armyworms, causing NPV epidemics that kill the caterpillars and halt the damage. “Field trials on armyworm outbreaks have shown NPV to be as effective as chemical insecticides at knocking out populations,” says David Grzywacz of the University of Greenwich’s Natural Resources Institute. “The virus can spread and persist on its own, multiplying its effect until the outbreaks are destroyed.” Although biological insecticides have been developed for other pests, their effectiveness has been limited by their high cost. But now a team comprising University of Greenwich and Brazilian scientists, and Tanzanian researchers, have developed a system to obtain NPV cheaply by harvesting dead insects from armyworm outbreaks infected by the virus. Using this approach, the cost of producing NPV in Tanzania can be reduced well below that of chemical insecticides. “If these armyworm plagues are to be kept in check, then a better and more cost-effective alternative to insecticides must be found,” says David Grzywacz. “Not only can such chemicals damage the environment and the health of those who handle them, but they are also beyond the means of many impoverished African farmers and the governments of affected countries such as Tanzania, Kenya, Uganda, Ethiopia, Zambia and Mozambique. I believe that NPV could be the answer.” The first aerial application
trials of NPV are planned for Tanzania in early 2004 to confirm its
effectiveness on a larger scale. ENDS |
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| For
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The
African armyworm caterpillar, that can devastate a year’s harvest in
just a few hours in some of the world’s poorest countries, could be
defeated using safe, cheap, environmentally-friendly biological weapons
developed by University of Greenwich scientists.