WITH more than 200 horse chestnut trees at Stockley Park, the Leaf Miner moth poses a very real threat to the 150-acre site.

Pieter Borchardt, estates eirector, is determined to fight back to maintain the eco-system, not only for the 7,000 people working there but also for the increasing variety of wildlife on the park.

He has enlisted the help of Dr Glynn Percival to trial an approach that not only avoids the use of indiscriminate and harmful pesticides but also reduces landfill.

He said: “The parkland setting is so very important to the wellbeing of everybody working on the park. It is an integral part of how we add value to our professional lives.

"In addition, we owe it to the heritage of the park to look after the flora and fauna for future generations.”

The horse chestnut Leaf Miner was first reported in the UK in 2002 and has since spread to most of England.

The effects of this moth on the horse chestnut tree have been devastating. Severely damaged leaves shrivel and turn brown by late summer and fall early.

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Untreated trees will eventually defoliate and decline, leaving them vulnerable to other diseases. Once established, the moth is hard to combat unless frequent insecticide sprays are used.

For these reasons, a unique management technique was evaluated on five horse chestnut trees located at Stockley Park by Dr Glynn Percival, head of research for Bartlett Tree Research Laboratory at Reading University. 

The results 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 combination of organic products including chitin (a waste sea food product), phosphites (natural fertiliser), biochar (a form of activated charcoal) and pure mulches i.e. a mulch made from a single tree species, such as willow or eucalyptus.

The treatment been shown to “switch on” a plant's own defence mechanisms and make it naturally more resilient to attack. Importantly, all of the products used in the study were derived from waste or natural compounds, which could have ended up as landfill.

Dr Percival said: “My aim is to make people think differently about tree health and look for more sustainable ways to deal with tree pests and diseases.”