Each year, the Royal Horticultural Society release their Top 10 pests and diseases, according to the enquiries they receive from gardeners.
The top pests of 2019 were:
Box tree caterpillar topped the lists in 2018 as well and is becoming much more widespread, so more gardeners are on the lookout for it. According to the RHS, it brings in more enquiries than the rest of the top five combined. Luckily, the product manufacturers are working on ways to deal with it, including pheromone traps to indicate when is the right time to act.
Fuchsia gall mite causes much despair, but is treatable with either a systemic insecticide or a predatory mite.
The increase in biological controls means that the bug-eats-bug approach is getting easier, especially in a greenhouse. There will always need to be a few pests, to keep the predators alive, but they will be under control. For more information, see www.dragonfli.co.uk
The Top 10 diseases of 2019 were:
Honey fungus is often mis-identified when a plant dies, but the honey-coloured toadstools in late summer and black “bootlace” strands beneath the bark are a sure sign. It is present in many gardens and spreads slowly, killing susceptible species, particularly if they are already under stress due to under-feeding or drought.
Brown rot of fruit and blossom wilt are caused by the same fungus and you can help matters with this and rose black spot by good hygiene in the garden. Clear away all fallen leaves in autumn and remove any mummified fruits left on the tree to deprive the spores of an overwintering site. Use a winter wash while the plant is dormant and apply a fungicide just as the buds begin to break in spring.
Any fungicide works better as a protective layer over the leaf to stop the spores entering, rather than to try and fight the problem after it has taken hold, but never spray fruit trees while they are in flower as the smell deters pollinating insects from approaching.
See our Plant Doctor section for more information and help.
This story was published on: 13/03/2020
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