Scarletrotting

Scarletrotting is a common fungal disease affecting various plant species, particularly those in the rose family. It is caused by the fungus *Botryosphaeria dothidea*. The disease is characterized by the development of sunken, reddish-brown to dark brown cankers on stems and branches. These cankers often appear as the plant grows, particularly on younger tissues.

Symptoms can include dieback of branches above the canker, wilting of leaves, and in severe cases, the death of the entire plant. The margins of the cankers are often well-defined. Under moist conditions, small, black fruiting bodies (pycnidia) may be visible within the canker, which are characteristic of the *Botryosphaeria* genus.

Scarletrotting thrives in warm, humid conditions and can be spread by rain splash, wind, and infected pruning tools. Plants weakened by stress, such as drought, extreme temperatures, or insect damage, are more susceptible. The fungus can enter the plant through wounds, natural openings like leaf scars, or lenticels.

Management of scarletrotting focuses on cultural practices and sanitation. Removing and destroying infected branches is crucial to prevent further spread. Pruning cuts should be made well below the infected area. Tools used for pruning should be sterilized between cuts to avoid transmitting the fungus. Maintaining plant health through proper watering, fertilization, and avoiding excessive stress can also help reduce the incidence of the disease. While fungicide applications can offer some protection, they are generally most effective when used as a preventative measure or in conjunction with good cultural practices.