Common juniper pests and diseases: how to recognise them

At a glance

How to grow common juniper · All pests and diseases

Pests

• Scale insectsSmall round or oval bumps on stems and along leaf veins, mostly underneath, that do not move and look like shells or scabs.Photo: BARAKAT2011, CC BY-SA 3.0, Wikimedia Commons

Diseases

• Honey fungusBranches die back over several years, or the whole plant dies suddenly in hot dry weather; leaves are smaller and paler, autumn colour comes early, and a last unusually heavy flowering or crop may come just before death.Photo: Stu's Images, CC BY-SA 3.0, Wikimedia Commons
• Pear rustBright orange spots on the upper side of pear leaves in summer and early autumn.Also called: European pear rust, pear trellis rustPhoto: Maurice Flesier, CC BY-SA 4.0, Wikimedia Commons
• RustPale spots on the upper leaf surface, with raised powdery pustules mostly underneath; on beans they often have a yellow halo.Photo: Rasbak, CC BY-SA 3.0, Wikimedia Commons

Which common juniper problems need quick action?

These spread or do lasting harm fast; check the plants and start treatment the day you see them.

• Honey fungus: Peel back the bark at the base — a creamy-white, paper-thin sheet of fungus between bark and wood that smells strongly of mushrooms confirms it; the bark at the base may crack and bleed.

Plants with many of the same problems

• Blackcurrant (3)
• Gooseberry (3)
• Pear (3)
• Redcurrant (3)
• Rose (3)
• Apple (2)
• Gloxinia (2)
• Grape (2)

Which plants each problem affects: sources

The links between these problems and the plant were checked against these pages.

1. extension.umd.edu/resource/scale-insects-indoor-plants
2. ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html
3. rhs.org.uk/disease/honey-fungus
4. rhs.org.uk/advice/pdfs/honey-fungus-host-list.pdf
5. rhs.org.uk/disease/pear-rust
6. pnwhandbooks.org/plantdisease/host-disease/juniper-juniperus-spp-pear-trellis-rust
7. plagas.itacyl.es/roya-del-peral
8. rhs.org.uk/disease/rust-diseases
9. rhs.org.uk/disease/leek-rust