Pear Decline

Symptoms

Premature autumn-like leaf reddening in mid-summer, premature leaf drop in late summer, undersize tasteless fruit, gradual decline over 2-5 years, asymmetric limb collapse.

Plants affected

• European pear

Easily confused with

• pear psylla

  How to tell them apart: Candidatus Phytoplasma pyri (Pear Decline) is a systemic, vascular pathogen: look for whole-tree symptoms — premature autumn-like leaf reddening and upward leaf rolling in mid- to late summer, sparse weak growth, small leaves, and a slow or sudden general decline. A diagnostic sign is a brown necrotic line in the phloem at the bud union when you peel back the bark at the graft. There is no insect, no sticky honeydew and no black coating; the damage is uniform across the canopy and progressive year on year. It is a common, established disease in EU pear-growing areas and is managed routinely as part of normal orchard care (vector control and replacing severely declining trees), with no quarantine reporting required. Cacopsylla pyri (pear psylla) is the insect vector you can actually see: tiny 2-3 mm winged or wingless cicada-like nymphs and adults clustered on shoot tips, leaf undersides and in leaf axils, producing copious sticky honeydew that drips onto leaves and fruit and turns into shiny black sooty mould. Reddening from psylla is patchy and tied to feeding sites and honeydew rather than a clean whole-tree pattern, and you will find the live insects, cast skins and ants attending the honeydew.

Common questions

How do I recognise Pear Decline on European pear?

Premature autumn-like leaf reddening in mid-summer, premature leaf drop in late summer, undersize tasteless fruit, gradual decline over 2-5 years, asymmetric limb collapse.

Do I have to report Pear Decline?

No. Pear Decline is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is Pear Decline treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.