Using foreign bugs to fight foreign plants... GENSUI

*imagines epic godzilla style battle between giant plant and giant bug*

It amazed me when I read how much it costs to control the Japanese knotweed in Britain - literally millions of pounds every year. The comparatively small outlay on the introduction of a biological control should be extremely cost effective.

As nestOr mentioned, careful testing and field trials have been undertaken. The scientists are obviously mindful of the mistakes from the past where so many ill thought out introductions have been detrimental. As an example, on a recent trip to Hawaii I saw mongeese (doesn't it sound more natural than "mongooses") near Diamond Head. Apparently the mongoose was introduced to control rats which were damaging sugar cane crops. Unfortunately, the rat is mainly nocturnal whereas the mongoose is diurnal. No problem for the mongoose which eats native fauna instead!

Interestingly, the tender spring shoots of Japanese knotweed are edible and are one of a number of wild vegetables which are collectively known as 山菜 (さんさい).

If only the Victorian gardeners had been able to study RTK before introducing it to England. It is called 虎杖 (いたどり) - hence the bug's specific name. RTK students will recognise this as "tiger cane". Would you want a tiger roaming your garden!

I'll just say one... make that two words. Cane toads.

Or take note of the virus Myxomatosis released in Australia to kill feral rabbits. It was highly successful... until rabbits became immune and were breeding more than ever with the virus often in their systems. The worse part is, prior to its release it was usual to see rabbits hanging up at your local butchers as a food source (presumably not just for decoration). Now that there's more interest in wild foods and foraging and the like, people are more willing to cook rabbit, but you can't just go and cull rabbits to protect the environment and pass them on as a gourmet food source because of the virus. What a waste! I just don't know why people think this is a good idea. Creatures can eventually adapt to their environment and do untold damage in ways you can't necessarily test for which is the issue. Erm, I suppose on the other hand the local environment, um, might be completely destroyed by these invasive species... but still! Surely there's a better way. :\

I found out about Japanese knotweed from a UK foraging blog actually. Apparently it does get eaten in the UK. They should ask Jamie Oliver or Nigella Lawson to make it look extremely delicious and people will go mad fer it. Instant new food industry, poor Japanese insects out of a job!

I'm a conservation biology BSc student, and I work for the Highways Agency as an ecologist to fund my studies. Japanese Knotweed is really a huge problem in the UK. Alongside much of the UK highway system we have extensive species-rich grassland - a haven for thousands of plant species (including many rare orchids) and hundreds of insect species. Japanese knotweed is one of the major threats we have to deal with, but nothing can get rid of it. It just devastates large areas, reducing biodiversity to just a few hardy species. Herbicides are not very helpful - they kill lots of other things too, and there is no herbicide specific enough to take out only the knotweed. We could use it as food (some people do, it tastes like rhubarb when young) but this wouldn't even come close to stopping it harming our conservation efforts.

Whilst utmost caution should be exercised in this introduction, it is only a trial. I welcome it, provided the trials are well conducted. It isn't really analagous to the rabbit/myxo thing as viral resistance evolves very quickly compared to resistance to a several million year old parasitic partnership such as the knotweed/Alphalara interaction.

I really hope this is successful.

p.s. nest0r that Mark Davis book is actually stirring up some excellent discussion in the conservation world. However, he's mostly talking about species which cause little harm (unlike the knotweed). In those cases, perhaps our resources would be better spent on something other than a futile battle against an inevitable and relatively harmless invasion.

Last edited by Blahah (2010 April 12, 4:30 pm)

Speaking of noxious weeds with Japanese names, another interesting case is that of kudzu in the American south. It's extremely invasive, covering telephone poles and whole buildings sometimes. But they've found a number of uses for it, not just as a food source, stock feed, or a fertilizer, but as a potential alternative fuel source of ethanol. Presumably if it works out and demand for ethanol goes up, there will be a monetary incentive to pull up the kudzu growing wild. Hopefully that happens rather than people starting farms to grow more kudzu. :p

Of course I was being a little flip earlier as I don't know much about the Japanese knotweed situation. I hope the trial in the UK is successful also. However in general it would be really great if viable alternative uses could be thought up, tested and implemented for these invasive species. At least in other cases (in Australia) it often seems like they go for the solution that will remove the most pests in the shortest amount of time without considering any future effects or other possible uses.