In this section:
Shothole
Cause
Fungus Stigmina carpophila
Affected
Most severe on apricots, but affects all stone fruit.
Symptoms
Infected leaves, the most common symptom, develop small brown spots with reddish margins. These then dry and fall out of the leaf, giving a shothole appearance. In severe cases premature defoliation of the tree may result. Infected twigs may develop irregular brown spots that ooze large amounts of gum.
On the fruit, small circular, deep purple spots appear first, but as the disease progresses, the symptoms differ according to fruit type. On apricots the spots become brown, raised and rough, giving the fruit a scabby surface. On peaches and nectarines the scabs develop into deep indentations.
Infected fruit have spots of gum and in severe cases cracks in the skin.
Conditions favouring
The shothole fungus survives in infected buds. It infects leaves stems and fruit during cool, showery weather in spring and autumn.
Control
Any affected twigs or shoots should be pruned out and disposed of to prevent the build-up of the fungus during the winter.
A copper oxychloride spray should be applied at the early budswell stage. If weather conditions are favourable for infection a further protectant fungicide spray (not copper based) should be applied between pink bud and shuck fall. In orchards where disease is present an autumn spray should be applied at two thirds leaf fall to reduce disease carryover.
