Pear Psylla (Pear Sucker)
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Treat, then re-check in 5–7 days
Pick off the worst material, apply the organic option below, and look again after five to seven days. If the spread continued, escalate rather than repeating the same treatment.
Carried by insects
An insect moves it plant to plant, so controlling the carrier matters as much as treating the symptom. Check for the vector before assuming the plants infected each other directly.
Safe to compost
No pathogen carries over on this material, so it can go on an ordinary heap with the rest of the garden waste.
When and where to look
Scout the planting while temperatures hold between 10°C and 30°C.
Rule these out first
Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.
The signs that lead here
Full problem lists for these crops
About
Pear psylla (Cacopsylla pyri) is a sap-sucking insect specific to pears. The honeydew it produces is the real problem: it coats the leaves and fruit, sooty mould grows on it, and a heavily infested tree looks scorched and sticky by midsummer.
Symptoms
Sticky honeydew on leaves and fruit followed by black sooty mould. Leaves curl and blacken, shoot growth is stunted, and fruit is russeted and small. Small orange or brown nymphs sit in the leaf axils.
Organic Treatment
A winter wash of plant-derived oil at bud swell kills overwintering adults and eggs and is the single most effective garden measure. Encourage anthocorid bugs and earwigs — put a straw-filled pot upside down in the tree — as they are the main natural predators.
Chemical Treatment
Approved products for pear psylla are limited and resistance is widespread. Where sprays are used, target the young nymph stage and never spray broad-spectrum products that wipe out the anthocorids keeping it in check.
Prevention
Avoid heavy nitrogen feeding, which produces the soft growth psylla prefers. Prune to an open habit, wash honeydew off with a strong water jet before mould establishes, and keep the natural predator population intact.
Crops at risk
Related problems
Pear Psylla (Pear Sucker) risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.