Pear psylla: how to recognise and treat it

Pest

Pear psylla — Photo: Mick E. Talbot, CC BY 2.0, Wikimedia Commons

Symptoms

Sticky honeydew on leaves and fruit, soon covered with black sooty mould.
Russeted, darkened fruit skin.
Parts of the leaf blade turn black, then the leaves yellow and may fall.
Weak shoots and spurs, dying shoot tips and reddish upward-rolled leaves when the psylla spreads pear decline.

Organic treatment

Spray horticultural oil in the dormant season; after a bad year, spray again just before bloom.
Spray insecticidal soap, azadirachtin or kaolin clay on the leaves.
Cut out water sprouts in early summer, which removes a large part of the psylla.

Chemical treatment

Abamectin with horticultural oil at petal fall; follow the label dose and pre-harvest interval.

Reference information, not a guarantee. Read and follow the label of any product: dose, safety and the days to wait before harvest.

Prevention

Keep nitrogen feeding low so the tree does not keep making soft new growth.
Avoid hard pruning, which triggers many new shoots.
Keep trees growing steadily with proper watering and feeding.
Protect predatory bugs, lacewings and ladybirds that eat psylla eggs and nymphs.

Plants it affects

Pear

Sources

Figures checked against these sources.