A treated horse chestnut (right) alongside an untreated tree.
With more than 200 horse chestnuts on Stockley Park, Uxbridge, the leaf miner moth poses a very real threat to the habitat of the 150-acre site.
Pieter Borchardt, Estates Director at the business park, is determined to fight back to maintain the ecosystem, not only for the 7,000 individuals working there, but also for the increasing variety of wildlife on the park. He has enlisted the help of Dr Glynn Percival, Head of Research for Bartlett Tree Research Laboratory at Reading University, to trial an approach that not only avoids the use of indiscriminate and harmful pesticides, but also reduces landfill.
The horse chestnut leaf miner (Cameraria ohridella) was first reported in the UK in 2002. Untreated trees will eventually defoliate and decline, leaving them vulnerable to other diseases.< Once established, the moth maintains exceptionally high rates of infestation, unless frequent insecticide sprays are used. For these reasons, a unique and environmentally benign management technique was evaluated on five horse chestnut trees located at Stockley Park by Dr Glynn Percival. The results of this technique have shown a noticeable improvement in the health of the trees, compared with neighbouring untreated trees.
The soil around each tree was treated with a unique combination of organic products including chitin (a waste seafood product), phosphites (a natural fertiliser), biochar (a form of activated charcoal) and pure mulches, i.e. mulches made from a single tree species such as willow or eucalyptus. These soil amendments have been shown to ‘switch on’ a plant’s own defence mechanisms and make it naturally more resilient to attack.
Dr Percival said,
‘By boosting the tree’s own immune system, using natural waste materials, the tree becomes more resilient to not only the leaf miner moth, but to other pests and diseases. My aim with this research is to make people think differently about tree health and look at more sustainable ways to deal with tree pests and diseases.’