Honey fungus and box tree caterpillar main culprits
The most common plant health problems last year were honey fungus and box tree caterpillar, according to the Royal Horticultural Society (RHS).
Now in its 22nd year, the annual ranking is based on gardeners’ queries to the charity’s experts.
However, I feel this is possibly skewed in favour of the south – I’d love to see separate results based on Northern England and Scotland. There are not many small, urban/suburban gardens with box hedges, are there?
In 2017, box tree caterpillar returned to the number one spot after dropping to number seven in 2016. It’s common in London and the Home Counties. Box also had to suffer box blight and volutella blight.
New problems to worry about
New in the chart this time are kerria twig and leaf blight.
The honey fungus has retained the disease top spot which it has held since the statistics were first published.
RHS research aims to help gardeners manage the disease that attacks and kills the roots of perennial plants before decaying the wood.
Pests and diseases to watch this year include fuchsia gall mite which makes its fourth and highest appearance in the top ten since its discovery in the UK in 2007.
Fuschia gall mite spread
Mites have now reached South Wales and Cheshire, which cause the shoots and flowers of fuchsias to distort.
Changing weather conditions, the withdrawal of fungicides and the use of highly susceptible cultivars is expected to see a rise in the number of diseases of edible crops such as apple and pear scab and pear rust.
Gerard Clover, RHS head of plant health, said: “This year’s pest and disease ranking points to the continuing problems inflicted on gardens by old foes like honey fungus but also new and emerging threats like box tree caterpillar, fuchsia gall mite and kerria twig and leaf blight.
‘Xylella is a game changer’
“With new pests and diseases emerging in continental Europe, it has never been more important that people get to grips with what is going on in their gardens.”
The RHS is adopting six new principles that will guide its activity and is hiring three new senior staff who will oversee plant health issues.
This includes Xylella fastidiosa which the RHS has labelled a ‘game changer’ for gardeners and the horticultural industry.
More information is available at www.rhs.org.uk/science/plant-health-in-gardens/plant-health-policy.