Why do I think that this will end badly? From the UK:
Japanese knotweed was first introduced as an ornamental plant in the 19th Century. But with no natural enemies in the UK it soon raged out of control, wiping out surrounding wildlife and even destroying buildings. The invasive species, that can grow up to 13ft tall and break through concrete, causes around £150 million worth of damage every year.
Gardeners tried starving it of water, soaking it in toxic weedkiller and simply just ripping it up, but nothing worked – until now.
A tiny insect called a psyllid, about the size of a grain of sand, was found to fell the knotweed within a few weeks and is now to be introduced to sites across the country. The plant-jumping lice lay eggs on the weed and the hatched larvae suck out the sap. (Louise Gray, The Telegraph [UK])
The citizens of the UK have been assured that the new bug has been thoroughly tested and won’t itself become a pest. And just to be sure, they are testing it at three “secret sites” where they will be “closely watched.” And if while watching they see a problem? Well, they don’t say what will happen if there’s a problem, since they will be letting this remedy out into the wild. The genie will be out of the bottle.
While this is being pitched as a huge boon to gardeners, the quotes in the article were from civil engineers, for whom the Japanese knotweed is an expensive problem when they wish to build on overgrown lots. Anyway, what could go wrong? These are tiny insects who only like to eat the Japanese knotweed. When they’ve eaten these all up, I’m sure they’d never develop an appetite for any other meal. Like those roses the English love so much.
According to The Telegraph the UK has never used biocontrol before. So they are playing catch up and with this brilliant idea, can truly be said to be entering the 19th century.