Why Do My Apricot Leaves Have Holes in Them?

Clean, round or angular holes punched through the leaves of an apricot tree are the defining symptom of shot hole disease, caused by the fungal pathogen Stigmina carpophila (formerly Coryneum carpophilum). The holes form when the infected leaf tissue dies, dries, and falls out of the surrounding healthy leaf — leaving gaps that look as if someone fired a shotgun at the foliage. A tree that loses most of its leaves by midsummer due to shot hole is significantly weakened and loses productive capacity for the current season.

How shot hole develops

Stigmina carpophila overwinters in infected buds, bark, and on fallen leaves under the tree. In spring, spores are released during wet periods and land on young, newly opened leaves. An infection spot — a small brown, purple-edged circular lesion — develops, and within days the infected tissue dies and falls away, leaving the characteristic hole. Warm, wet spring weather drives rapid spread. In dry years the disease is much less severe.

Prevention: copper fungicide

The most effective intervention is copper-based fungicide (Bordeaux mixture or copper oxychloride) applied in autumn at leaf fall and again at bud burst in early spring. The autumn application reduces the overwintering fungal population on the bark; the bud-burst application prevents the first wave of spring infection when leaves are most vulnerable. Follow label rates and timing.

Sanitation

Fallen leaves in autumn carry overwintering inoculum. Rake up and remove all fallen leaves from beneath the tree — do not compost them. Removing the fallen leaf layer reduces the spore load available to infect the tree the following spring. This is simple, free and consistently reduces shot hole severity.

Improving air circulation

Dense canopies stay wet for longer after rain or dew, creating extended periods of surface moisture during which spore germination and infection occur. Summer pruning that opens the centre of the tree to light and air reduces leaf wetness duration and lowers disease pressure. This is particularly important for wall-trained trees where the canopy can become very dense against the wall surface.