Slugs and snails are back at the top of the pests chart, after a year in which people spent more time tending their gardens, said the Royal Horticultural Society.
The charity’s 25th annual pest and disease ranking – based on enquiries from gardeners – reveals that slugs and snails, a mainstay of the rankings over the years, topped the 2020 list for the first time since 2017, with gardeners reporting damage to crops such as potatoes and beans.
Vine weevils were in second place again but the box tree caterpillar, which strips box plants of their leaves, slipped to third place in 2020 from first in 2019, as reports of the invasive species fell 40%.
The RHS said research had found box tree caterpillar spread slowed last year following rapid growth into northern England and Wales.
On the plant disease front, honey fungus was again top of the ranking, followed by pear rust, then leaf spot and canker of prunus.
The RHS said its gardening advice service had an 88% increase in pest and disease enquiries last year as people spent more time in gardens amid the Covid pandemic and lockdown restrictions.
Andrew Salisbury, principal entomologist at the RHS, says: “The pests and diseases that gardeners commonly face on their plots has fluctuated over the last 25 years but some age-old problems persist.
“With gardens taking on a more important role in supporting wellbeing and the environment it’s important that research into management and mitigation of them continues and our rankings help inform this focus.
“It’s also imperative that we continue to anticipate future threats such as the disease xylella, which is already present in Europe, and the marmorated stink bug, to protect our gardens for the future.”
Top pests 2020
1. Slugs and snails
2. Vine weevil
3. Box tree caterpillar
5. Woolly aphid
6. Glasshouse red spider mite
7. Fuchsia gall mite
8. Glasshouse thrips
9. Rosy apple aphid
10. Capsid bug & glasshouse mealybug
Top diseases 2020
1. Honey fungus
2. Pear rust
3. Leaf spot and canker of prunus
4. Rose black spot
5. Bracket fungi
6. Powdery mildew of prunus
7. Blossom wilt of fruit trees
8. Phytophthora root rots
9. Rose powdery mildew
10. Brown rot of fruit