Japanese Knotweed vs. Psyllids: The Encounter In The UK

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Japanese Knotweed vs. Psyllids: The Encounter In The UK

Monday, September 28th, 2009    Subscribe To Our Feed

Have you been constantly annoyed by the time and energy, much less the money, that you put into completely eliminating Japanese knotweed from your garden, only to discover the area green and healthy with fresh sprouts a few days after?  This weed has been a big problem in the UK for sometime.  Not long after its launch in the 1800’s, the plant has raided many of UK’s land area and wastelands.  It has caused a real threat to the native plant species as they are very resistant to several techniques of control.  They displace local plants and lower the species range in the region.

There have been numerous ways used to deal with the spread and growth of the invasive Japanese knotweed, from herbicides to carefully removing the plants to adding its real parasite, Aphalara itadori.  These psyllids, as they are named, are sap-sucking insects which are also native to Japan from where the weed also originated.  Aphalara itadori  is named jumping plant louse. The premeditated introduction of this psyllid is backed up by scientific investigations from CABI but not everybody are ecstatic to the concept.

The research has reached over some six years, testing more than 200 control measures and has concluded that the jumping plant louse is the best alternative amongst all these.  It further lays down the reason that renders this psyllid the perfect option, which is the fact that it is a sap-sucking insect, thus it is host exclusive.  This is to pacify claims that the insect may transfer to local plants once it is brought into the ecosystem.  The insect will inhibit its growth and make it less aggressive.  The insects will suck the sap from the plant in their nymph stage.  These may not totally put an end to the harmful weed.  The point is to make them more adaptable and make the control process more viable in due course as well as less expensive.  An astounding sum of approximately 1.6 billion pounds yearly is exhausted on eliminating Japanese knotweed.

The addition of a non-indigenous species into the UK poses a biological danger, many doubting Thomases proclaim.  What happened to Australia after introducing cane toads as a natural pest control for beetles in 1935, just turned into an ecological threat today, may likewise happen to the UK.  Another example was the introduction of harlequin ladybirds in a number of European countries for ecological control but it just needed them little time to cross over the English Channel and put the British ladybirds at risk.  Japanese knotweed removal by the addition of the jumping plant louse is going to be a long discussion.  The face off of these two, the Japanese knotweed and its principal rival, the jumping plant louse, will not happen in the near future.