Pests and Diseases to look out for this Autumn - check your laurels for powdery mildew and your trees, hedges and shrubs for vine weevil
Autumn is a good time of year to get ahead when it comes to treating pests and disease in the garden. It’s still warm enough for treatment to be effective and you can get any problems cleared up before winter sets in.
There are a couple of particular problems to look out for in the garden this month.
Powdery Mildew on Laurels
If your laurels are suddenly showing a white powdery film on the leaves and the newer growth is puckering up and twisting, then you have powdery mildew, which quite often appears at this time of year.
This disease is not fatal but will defoliate the newer growth. There are two ways to control this. Firstly, the non-chemical way is to prune off the infected growth and dispose of well away from the infected plants.
The second way is to spray with an approved fungicide. The Royal Horticultural Society carry an excellent up to date list of approved chemicals.
In the long term, to help prevent the disease coming back, you need to get your plants into good health for the following year by feeding them in the spring and making sure that there is good air circulation near the plants as high humidity encourages this disease.
Vine Weevil on trees, hedges and shrubs
The second and potentially more ominous pest is vine weevil. This is a naturally occurring native dull black insect approximately 9mm long with six legs and with a dirty yellow mark on the wing cases. The adult causes irregularly shaped notches in the edges of the leaves but the real damage is done to the roots by the grubs which can eat the vast majority of the root system causing the plant to wilt and die.
The adults lay the eggs in August and these hatch over winter into c-shaped white legless grubs with light brown heads and are up to 10mm long. To reduce this pest remove all dead leaves around affected plants as this is where the adults hide during the day.
Secondly encourage natural enemies of vine weevils and their grubs such as birds, frogs, toads, shrews, hedgehogs and predatory ground beetles.
Perhaps the best method of control is to use a microscopic worm called a nematode. Nematodes can be watered onto the soil around affected plants during September and early October while the soil is still warm enough for them to be active.
These nematodes work their way through the soil searching out vine weevil grubs which they burrow into to reproduce and multiply which kills the grub. The nematodes will then move on to search out more grubs. This method of control is very effective if applied correctly, is very safe for both you and the environment, and is pest specific so it will not kill beneficial insects. Nematodes can be bought on line from a number of suppliers.
If you have any specific concerns about your plants this autumn, please get in touch.