What Are Black Spots on a Golden Cane Palm?

Identification

• Leaf spot diseases of palm trees are caused by different fungi types, most of which only affect the leaf blades. According to the University of Florida, all palm tree species are susceptible to leaf spot, including golden cane palms. Leaf spot diseases are characterized by dark lesions on palms. These fungal diseases can become severe and black spots may rapidly enlarge.

Signs and Symptoms

• Golden cane palms with leaf spot disease, first develop tiny water-soaked lesions on infected leaves. These lesions turn gray, reddish-brown and finally black. Halos of color may encircle the black lesions and is most often a different color, such as yellow or gray. Palm trees with leaf spot disease have discolored foliage and leaves of all ages are affected.

Cultural Control

• Leaf spot diseases are spread by fungal spores located in the black lesions on the leaves of infected palms. Water, wind and insects spread these spores to other plants in close proximity, making sanitation an important part of disease control. Removing all leaf litter and plant debris from infected palms and destroying it prevents the spread of fungal spores. Irrigate early in the day, so palms have time to dry out during the daytime before cool nighttime temperatures arrive. Avoid injuring your palms during pruning, as wounds provide fungi with easy access to the plant.

Chemical Control

• Fungicides are available for palms with leaf spot diseases. However, fungicides are only effective when applied in conjunction with water management, injury prevention and sanitation. Applying insecticides to your palms helps keep insect damage at bay and prevent wounds.