RHS reveals most prevalent plant diseases for gardeners in 2022

The annual list of the most prevalent plant diseases has been released by the Royal Horticultural Society.

The annual disease ranking shows that fruit trees and fruit crops are at the front line of impact from the extreme weather conditions, brought about by climate change.

Periods of drought, high temperatures, heavy rainfall cause plants to become stressed and therefore more susceptible to problems.

The list of the top ten plant diseases in 2022 are

Honey fungus
Phytophthora root rot
Powdery mildew on Prunus (cherry laurel)
Rose black spot
Peach leaf curl
Brown rot of fruit
Silver leaf
Apple and pear scab
= Pear rust
= Apple and pear canker
= Bacterial leaf spot and canker of Prunus (fruit trees)

Honey fungus is again at the top of the list, having taken the number one spot every year since the list was first published in 1995. The fungus has a large host range of more than 140 garden plants, particularly large woody ones, and results in dramatic symptoms, including death, cracked and bleeding bark and failure to flower. Stress is known to leave plants more susceptible to honey fungus.

For the coming year, the RHS advises gardeners to adhere to the mantra: 'right plant, right place' in order to help avoid plant disease. Good plant care and hygiene is also encouraged. Here are more tips for gardeners:

• Mulch plants now, while the soil is still moist, so that water can be trapped ahead of any drought.
• Prune dead or diseased material at the right time of the year - pear and apple in winter, summer for prunus.

Liz Beal, RHS plant pathologist, said: “The prolonged drought last summer followed by a wet and mild autumn provided the perfect conditions for fungi to spread, so it is unsurprising that we have seen an increase in many diseases, particularly in fruit trees which can be very susceptible to rot and other fungi. Gardeners can help combat many of the most common diseases in our ranking by practising good hygiene, keeping tools clean and removing diseased plant material from their gardens. Providing the preferred conditions for the plants in your garden can also help ensure plants do not become stressed and less able to fight off infection.

“The RHS is also calling on gardeners to remain vigilant to new plant problems. For example, blueberry rust could become more of a concern as an increasing number of gardeners try out crops that were previously the preserve of warmer climates.”