Bud Rot of Palm Diagnostic Guide
Bud rot of palm is most often caused by Phytophthora palmivora, but can also be caused by Thielaviopsis paradox. Bud rot affects the apical meristem. This can lead to malformed new leaves and chlorotic new leaves that lead to plant mortality.
Trees at Risk
Palm species, including but not limited to Areca palm, Bismark palm, Bottle palm, Carpentaria palm, Chinese fan palm, and King palm.
Chinese Fan Palm
Sign of Damage
- The first symptom is discoloration and wilting of the spear leaf and wilting/discoloration of the next youngest leaf. In severe cases, the spear leaf easily pulls from the bud.
- As the problem progresses new leaves will not form and the palm will have an open-topped crown.
- Eventually leaves become desiccated, turn brown, and collapse.
- Close examination of the leaves, especially the spear leaf, may reveal blighted areas on the blade. The leaf base often has distinct brown/necrotic areas.
- Because the bud is dead, no new leaves emerge. Older leaves remain healthy for months after the bud had died.
- Bud rot is also observed in association with cold damage. Cold damage allows entry of secondary pathogens.
- Laboratory diagnosis is required before fungicides can be applied. There are two pathogens that may cause palm bud rots in Florida - Phytophthora palmivora and Thielaviopsis paradoxa. In small, juvenile palms, other common soil-borne pathogens may cause bud rot. Laboratory diagnosis is required to determine the exact cause of the symptoms observed.
- Reduce overhead irrigation and improve drainage to discourage standing water.
Tree Injection using Agri-Fos Plus
Dosage: 2 tsp - 1 fl oz/tree (Dilute with water to give final injection volume of 1 fl oz - 2 fl oz of water and AGRI-FOS®. Inject into the trunk or root system) Timing: Applications should coincide with periods of wet weather Re-Treatment: As conditions persist
Soil Application using Agri-Fos Plus
Dosage: 6 1/4 – 12 3/4 fl oz/100 gal of water (25 gal of solution to an area of 100 sq ft Follow application with irrigation. Repeat as required. Limit of one application/month) Timing: Applications should coincide with periods of wet weather Re-Treatment: As conditions persist
A Diagnostic Guide is designed to help you identify a pest issue and management solutions. Always refer to product label for all rates and approved uses. Some images courtesy forestryimages.org. Use of the images does not imply endorsement of treatments by forestryimages.org