A modest proposal

Image of Robin Lane Fox

All is not lost for Britain’s beleaguered specimen trees. Owners of crucial trees in a garden or a main sightline can still protect them. It is time for the young to rally against fungus and insects and be sent out to clean the country up.

At Kew I have just had the chance to vent my annoyance on every marauding beetle within range. The jobless would love it. The answer is to shoot diluted chemicals into each tree by directing a pressure-hose at the branches and trunk. As you can see, it is more gratifying than wandering around as a man in autumn with a leaf-blower. The pressure jet has force and gains height. With practice we can each pressure-hose up to 50 trees a day. At Kew they have been giving a yearly pressure-hosing to their huge historic Turner’s Oak, planted in 1798. There is not a sign of a bug or beetle on its trunk or canopy.

Scientists prefer apocalyptic culls, but containment is good enough for most of us. I therefore propose a British Arboreal Campaign. Anyone without a job will have to enlist for National Tree Service. They can have fun dressing up in protective overalls like space invaders. They can have even more fun with one of the preventions which I have now had explained to me. Our revered FT economist Samuel Brittan has been suggesting the merits of a helicopter drop of bank notes to get growth in the economy moving. I propose to invert the idea and have a bank-flush from the ground up. Banknotes can be “printed” to pay for it and the “drop” will be chemical, not fiscal. Specimen trees all over the country should be declared by local communities and registered by their councils. Squads of otherwise-jobless in overalls can then go out and give them a safe future until scientists come up with a better idea. The fresh air will be good for everyone’s health and there will be a crusading glow of patriotic rescue to each day’s work. If more finance is needed, the government can cancel its high-speed train link through the Midlands and put our trees’ future first. Leafy marginal suburbs with swing seats in the next election would doubtless be given priority. If their trees are protected this spring, they will be showing lovely green results in 2014. What other programme has the coalition devised which is certain to work visibly in time for the next national vote?

There are various options, explained to me by the professionals at FA Bartlett Tree Expert Company, who have been active since 1907 and hold a Royal Warrant. One is to pressure-spray a tree at risk to bugs with a commercial product called Bandu. Its active ingredient is deltamethrin and it kills insects on the tree indiscriminately. It is extremely effective. It kills off caterpillars and moths, bugs and borers. It clears the horrible leaf-miner from horse chestnuts and the oak procession moth from oaks. Nobody yet knows what else it may clear from the tree’s adjoining soil, but I would rather have a healthy tree and worry about this highly localised fallout later. In the picture for this piece I am spraying water, but I look so pleased because I am telling myself that next time it will be Bandu.

Against all bugs, but not caterpillars, the winner for my money is called Admire. Its active agent is imidacloprid, the compound pioneered by Bayer nearly 30 years ago. I rate it second only to the contraceptive pill as the greatest chemical contributor to our modern lives. Imidacloprid has been rigorously tested and approved worldwide. It is a crushing answer to devoted “organic” fantasists. None of the “organic” lemons in our shops, and none of the “organic” tomatoes, would even exist nowadays without commercial use of imidacloprid. They would have been wiped out by citrus leaf miners and so forth if imidacloprid was not being used to kill the bugs off. It works wondrously, I now learn, against the horse chestnut leaf-miner.

The neatest method is not to spray it but to inject it. I have now watched demonstrations of how to inject a plane tree by tapping a few short pins into its trunk, causing minimal damage to the bark, and then pumping in Admire through an injector pump, in this case one called Arborjet. The job is so easy that even a digitally challenged pensioner on the dole could learn to do it within an hour. It is quick and simple, and so long as you wear gloves, a mask and protective clothing, it is safe. I would rather inject an oak than bicycle through car fumes to a Jobcentre.

Here is the unexpected news. Admire will kill off the pest which is turning the leaves of our horse chestnut trees brown and weakening their overall energy by up to 40 per cent. Bartletts quoted me an indicative £120 for a two-hour professional visit to protect my horse chestnut, including travel and chemicals, or about £500 for a day. If you want a tree to be pressure-sprayed, the necessary platform is included in the price but the access must be easy. They estimate they can spray 40-50 trees a day. Bartletts consider that ever better technology and chemicals for trunk injections are waiting for a licence. If our officials give it a push, the trade can be transformed.

Transformation has already happened if you delve into the past of a newly licensed compound called Subdue. Wondrously, this one will curb phytophthora, the deadly pathogen which is attacking larch trees, rhododendrons and much else. It was licensed suddenly this summer because some of the trees bussed in for the Olympic Park were found to be carrying phytophthora. This sort of “instant” planting is exactly what best imports diseases on globally sourced specimens. It sits uneasily with all the Olympic publicity for “natural” gardening and the Park’s swaths of grasses and perennials. If the government can ease the path for Subdue, surely they can ease it for other injectable compounds before there are no trees left to protect.

What about the moths and caterpillars, which imidacloprid does not touch? Never fear, we now have Dimilin Flo, a commercial compound which is based round diflubenzuron. It knocks them all out. Kew is extremely glad that this godsend exists for their specimen trees, which would otherwise teem with toxic moths.

Until National Tree Service is introduced, ask experts like Bartletts to quote you for cleaning up the best trees in your garden. For the price of a TV licence you can have at least four green years on your horse chestnut after one treatment. There will be enough change left over to buy a bottle of champagne to toast its revival. Visit www.bartletttree.co.uk for details of treatments and diseases.

Of course I have also logged in to sites like just-green.com to find out whether ladybirds can help. They can, but not against very much. I am more excited by the non-stinging wasp in Bulgaria which is eating the chestnut leaf-miner. It needs fast-streaming through security tests and then it should be brought over here. I have also seen graphs of the effectiveness of spraying with soap or with a horticultural oil based on oil seed rape. The results are pathetic, warming my inorganic heart.

Maybe National Tree Service cannot afford to save entire ash forests. At least it will protect the best trees in the view. Like most of the nation’s fertile females, our trees now need to be jabbed. It has to be better than lobbing £20 notes from the sky on to dying treetops.

Copyright The Financial Times Limited 2017. All rights reserved. You may share using our article tools. Please don't cut articles from FT.com and redistribute by email or post to the web.