These wilted leaves and flowers turn brown and then become black giving the appearance of fire scorching. The infection may spread down into the twigs and may even involve large branches. Some of the larger ornamental trees develop extensive cankers on the main limbs as well as on the trunk. Some of the flowering ornamentals, such as the flowering quince, are susceptible only in the blossoms. This type of infection gives an appearance of frost injury and may be mistakenly diagnosed as such.
Infection occurs through unprotected wounds and through natural openings in the blossoms.