Japanese Knotweed is Dying Out

Just about everybody knows about the introduction of South American cane toads into Australia in 1935 by the Australian sugar industry. The experiment was a great success, for the toads. From a human point of view, the pest control has become a pest out of control. Instead of restricting their diet to the scarab beetles attacking the sugar cane, they made good of just about everything that moves in insectdom. To add insult to their success, the toads poison any predator that tries to make a snack out of one of them.

Japanese Knotweed in turn was introduced by the Victorians more than a hundred years ago into Britain. Meanwhile, the weed is a major pest that costs taxpayers 1.6 billion pounds a year to combat. The plant has a growth rate of 3ft per month and sends its roots down 6ft. Removing the pest means removing every particle of the roots as well, as it is able to reform from only particles of its roots. The weed is able to grow through concrete and asphalt and thereby damages buildings, roads, dams and other manmade structures.

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Japanese Knotweed has several scientific names, it is known as Fallopia japonica, Polygonum cuspidatum, and Reynoutria japonica.

Now the eminently gifted government of Britain has declared the Japanese psyllid Aphalara itadori which feeds on the sap of the knotweed to be no threat to other wildlife. If the government says so, I am sure the psyllid will do exactly as told. To back up their statement, ministers have cited a research by the Centre for Agriculture and Biosciences International in Oxfordshire. The scientists made an exhaustive trial run on 90 (sic) native British plants with the psyllid to prove that it will not attack anything but the Japanese Knotweed.

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Plants For A Future lists 7,000 edible, medicinal, and other useful plants alone on its webpage. Add to this some other plants, and the research on 90 plants by the institute mentioned becomes really impressive. There is no mention either of any tests having been made on birds or any other small predators that might feel inclined to take a nibble of psyllids. There is nothing like a well founded and exhaustive research by scientists to make you believe in a government statement.

For better or worse, licence has been granted to introduce and set free the Asian bug in Britain. With all probability, it will be another success story, the question is just for whom.

To cap it all up, the flunkies at the Daily Mail had the most amusing capture: “The psyllid dies out after destroying knotweed.” Quite so, dear David Derbyshire, that is why knotweed and psyllid are to be found well and alive in Japan to this day.