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, chlorotic new leaves, and lead to plant mortality.
Signs of Damage
- 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 dies
- Bud rot is also observed in association with cold damage; cold damage allows entry of secondary pathogens
Trees At Risk
- Palm species
- Free water is important to the development of this disease. It is most likely to occur during the rainy season, and the problem can be exasperated after tropical storms or hurricanes. It can also be a problem where overhead irrigation affects the top of the plant.
- Bud rot caused by Thielaviopsis can move beyond the bud into trunk tissue and degrade woody tissue.
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