Quince rust

Hawthorn twigs, fruits, petioles, thorns and leaves may be infected, with symptoms becoming visible about 7-10 days after infection. Fungal infection results in the production of abnormally large cells (hypertrophy), causing the host tissue to appear swollen. Infected hawthorn twigs have spindle-shaped swellings. Veins, a common infection site on leaves, swell and host the spermatial stage of the fungus. The spermatial and aecial stages of the fungus are produced on infected twigs, fruits, petioles, and at the base of thorns. Diseased leaves curl and die, but do not produce aecia. Infected tissue typically dies after aecial production, resulting in twig dieback.