How do I know if my tree is diseased?
Posted on: June 23rd, 2016
Unlike most other plants and shrubs in the garden, we expect trees to just get on with it. Compare an oak to a rose bush and it's hardly surprising – we will feed the roses, water them, spray them if we notice any pests... and ignore the oak.
A healthy tree has the amazing ability to adapt and survive, whilst withstanding the harshest of elements.
But just because they're big and strong doesn't mean they don't sometimes require our attention. They are living, breathing things and just like us, they can get sick. They can die. Even the mightiest tree can be felled by disease if they don't get the treatment they need.
And don't forget that we need trees just as much as they need us.
Trees provide homes for wildlife. They give us clean air, water and food. They are used for fuel to keep us warm. Yet the way we live can affect them in ways we cannot comprehend. Changing environmental conditions and non-native tree and plant species being introduced into the UK can mean an increase in disease and pests.
For example, Dutch elm disease completely changed the face of our landscape, with the loss of more than 60 million elm trees during the 20th Century. Acute oak decline is affecting mature oaks across England and Wales, the oak processionary moth not only risks trees but human health, and Sweet Chestnut blight, which has recently been found in the UK, killed approximately 3.5 billion trees in the first half of the 20th Century in the USA.
So how can I tell if a tree is diseased?
Are you concerned about the health of one or more of your garden's trees?
It is rare for a tree to be completely disease-free. There are millions of microscopic organisms that make a tree's bark and root tissue their home, but for the most part, trees can easily co-exist and continue to thrive with these pathogens.
But some tree diseases can take hold that the tree cannot easily fight off. When this happens you may notice:
- Discoloured blotches or dead areas on the tree's leaves – also called leaf blight
- Trees losing their leaves when they shouldn't – defoliation
- Root decay – broken roots or evidence of fungus in the roots
- Fungus spores in the tree's bark
- Dead branches
- Cracks and cankers – deep splits in the bark or holes where the bark is missing
- Decay – fungus or soft, crumbly wood
How can you treat a diseased tree?
You cannot effectively treat a diseased tree until you identify the disease or pest that is affecting it.
Once determined, there are certain fungicides available that can be used to control diseases on trees and shrubs. They tend to be injected into the tree trunk or the soil surrounding the tree and its roots. Other methods, such as pruning, fertilisation or changing watering habits may help to reduce disease.
However, it isimportant to speak to a professional if you are going to attempt to control a disease affecting your garden's trees. An arborist or tree surgeon can help to identify the disease and provide expert advice on the best treatments – if any – to control the problem.
You should also be aware that if the disease has affected the tree to the point where it has become dangerous, your tree surgeon is likely to suggest that it is removed for the safety of your home, garden and family.