Chosen insect feeds on invasive
species but not other closely related plants and cropsBiological warfare is to be declared on an alien invader,
Japanese knotweed, that swamps gardens and rivers, with the release of an insect to eat the virulent weed.The decision by the Department for Environment, Food and Rural Affairs is the first allowing one non-native species, a flying insect resembling a miniature moth, to control the seemingly unstoppable spread of an alien plant.However, it is likely to cause concern among
wildlife lovers because of a long history of human interventions in the natural world ending in failure, and sometimes causing worse problems than the original, as with the cane toad in
Australia.In a public consultation by Defra last year about 20 responses opposed the scheme, though 42 were in favour.The wildlife minister, Huw Irranca-Davies, said the fast-growing Japanese knotweed was estimated to cost £150m a year to control, and was able to grow through buildings and roads.Fallopia japonica has also been blamed for
flooding, by causing erosion to river banks and clogging up streams with dead plants."This project is not only ground-breaking, it offers real hope that we can redress the balance," said Irranca-Davies.Experts estimated in 2003 that it would cost £1.5bn to fund a physical clearance campaign for Japanese knotweed.Laboratory tests were started on pests from Japan which control the knotweed by feeding on sap from its stems, causing the plant to die back.The tests showed the chosen Aphalara itadori did not eat any other species, including closely related British plants and important crops.The psyllids – or plant-jumping lice, which grows to only 2-2.5mm – will be released at two sites initially, under close supervision.If these outdoor trials are a success the trials will be extended to another six sites, none of which Defra will disclose.The concept is similar to biological pest control practised by some farmers, using predator insects ...
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