Signs and Symptoms

Leaves of infected plants exhibit reddish-brown necrotic lesions often with concentric rings, surrounded by a reddish border or a light green halo. With the development of the disease, in case the disease is caused by fungi, black pycnidia forms on the lesion surface. Pycnidia contain one-celled, hyaline, fusiform to ellipsoid conidia, smooth with fine granular content, typical for Neofusicoccum parvum and sometimes also smaller one-celled, hyaline, rod shaped conidia with rounded ends called spermatia. In the final phase of disease development, necrotic lesions drop out of the leaves, leaving holes in the leaf that resemble damage from shot gun pellets (“shot hole” appearance).

Symptoms of a shot hole disease caused by Neofusicoccum parvum on ornamental Prunus laurocerasus in Serbia. (a) Leaves with a shot hole appearance, (b) brown necrotic lesion surrounded by a light green halo, (c and d) necrotic lesion with N. parvum pycnidia developed on a lesion surface, (e) close up of leaf with hole. Bars: a = 1 cm, b–d = 0.3 cm.