Phytophthora ramorum at Quarry Bank

Walking in the Northern Woods at Quarry Bank Cheshire

Over the last two years, the infectious plant disease Phytophthora ramorum has been repeatedly identified in the Northern Woods on the Quarry Bank estate. Find out how we're managing this virulent disease and preventing future outbreaks.

What is Phytophthora and how does it spread?

Phytophthora is a fungal-like plant disease that infects shrubs and trees, and spreads through its spores. The spores spread themselves by air or water, and can also be picked up by animals’ feet. Phytophthora is not dangerous to humans or animals.

Plants have no defence mechanism against the disease, so it slowly spreads throughout the plant, and will eventually kill it. Once a plant has Phytophthora, there’s nothing we can do to stop this, so we have to act to prevent the disease spreading in the first place. There are several different strains of Phytophthora; the most prevalent in our woodlands has been Phytophthora ramorum.

Where has Phytophthora been found at Quarry Bank?

Over the last two years, Phytophthora ramorum has been repeatedly identified in the Northern Woods on the Quarry Bank estate. The outbreaks have been in the Chapel Woods, an area of the Northern Woods. The outbreaks so far have been due to infected rhododendron plants.

When native species become infected with Phytophthora they are killed by the disease but they don’t spread it. However, there are several non-native species that play an active part in spreading the disease, including rhododendron and larch. It’s vital that we minimise the risk posed by these ‘carriers’ of Phytophthora.

What happens when there's an outbreak of Phytophthora?

When we have a suspected Phytophthora outbreak, we have to inform the Animal and Plant Health Agency (APHA), who visit us to take a sample for testing.

If the test comes back positive, then a legally binding Statutory Destruction Notice is issued to us by APHA, which requires us to destroy the infected plant, and also all the plants within a certain radius of it. That area is then treated with chemicals for at least three years. 

What actions are being taken to prevent future outbreaks?

As a preventative measure, we have decided to clear an area of larch trees near the Oxbow in the Northern Woods. Larch trees are highly susceptible to infection and there are a large number of trees in this area. This means that if Phytophthora was identified in the larch a Statutory Destruction Notice would have to be issued for a far greater radius than we have had to clear so far, ranging from 100 to 250 metres.

Should this situation arise, it would have a significant impact on native plants and trees in the Northern Woods, which would have to be destroyed within that radius.

We have been advised that the risk of the larch trees becoming infected is extremely high; therefore we have taken the decision to fell all the larch trees in the Oxbow area as a preventative measure to protect the rest of the woodland from infection.

Following that we’ll be removing rhododendron to try to prevent Phytophthora from returning in areas where we have previously had outbreaks. That work will be phased over several years.

After the larch trees have been felled, the area will be allowed to regrow naturally, guided by our woodland management plan created in early 2016. Some areas will also be left open, as before the larch was planted in the 1930s this area was open woodland pasture.

How you can help

You can still help us to stop the spread of this virulent plant disease through your visit by:

1. Paying attention to any site notices- infected areas may be cordoned off and felling/ clearance operations may be taking place

2. Keep dogs on leads at all times – This will reduce the spread of the fungal spores. 

3. Keeping to marked paths- to help reduce the chances of picking up contaminated soil or plant debris.

4. Cleaning your footwear- remove any soil or plant debris from footwear after each visit.

5. Not taking plants or cuttings - you could inadvertently introduce infected material into your own garden.

6. Monitoring the health of your own plants – familiarise yourself with the symptoms of Phytophthora by visiting  

Thank you for your help and co-operation