Why Does My Apricot Tree Have Spots on the Leaves?

Leaf spotting on apricot trees in the UK is most commonly caused by one of three conditions: shot hole disease (Stigmina carpophila), bacterial canker (Pseudomonas syringae), or early leaf curl caused by fungal pathogens. Each produces spots of a distinct appearance, timing and severity. Correct identification is essential because the treatments and management approaches differ significantly between them.

Shot hole disease

Shot hole disease produces small circular or angular brown or purple spots, typically 2–5 mm across, which appear on leaves from late spring onward. The tissue within the spot dies and eventually falls out of the leaf, leaving a clean, round hole that gives the disease its name. Heavily affected leaves may have dozens of holes and drop early. The pathogen (Stigmina carpophila) overwinters in infected bark and buds and releases spores during wet periods in spring and early summer. Copper-based fungicide sprays in autumn and at bud burst reduce infection. Improve air circulation through the canopy and collect fallen leaves in autumn.

Bacterial canker (Pseudomonas)

Bacterial canker causes irregular brown or yellow spots on leaves, often with a yellow halo around the brown centre. Leaves may eventually show ragged holes where the spotted tissue has died and fallen out — similar in appearance to shot hole but with a more irregular shape and yellow margins. The same bacterium causes canker lesions on branches (see the bacterial canker guide). Copper-based sprays in autumn at leaf fall and again at bud burst help manage both the leaf and bark phases.

Timing and severity

Both shot hole and bacterial canker are worse in wet springs. A tree that loses most of its leaves by midsummer due to either disease is weakened and less productive, but rarely killed outright. The priority is reducing the inoculum source: remove fallen leaves, apply copper in autumn and spring, and prune out any dead wood carrying canker lesions during dry weather in summer (late June to July).

Nutritional spots

Manganese or iron deficiency can cause interveinal yellowing rather than discrete spots but is sometimes confused with disease spotting on apricot. True deficiency spots are diffuse and yellowish rather than discrete brown circles. A soil pH test is the first diagnostic step — pH above 7.5 locks up trace elements.