Apple Proliferation
Apple proliferation
12 host plants
Last updated
This profile contains verified disease data from extension databases. Regional field notes and expert review are in progress.
Trees show witches' brooms, stunted growth, small deformed fruit, and late bud break in fall. This phytoplasma disease has no cure available to home gardeners. Infected trees may appear to recover but still carry the pathogen. Remove infected trees.
Send any trees that may have these symptoms to a diagnostic lab for confirmation of the disease, and never smuggle in budwood or trees. Always use certified planting material.
Quick Reference
Management
Young trees and newly infected trees are most severely affected; mature trees show variable symptom expression. Spring emerging buds and early summer growth show characteristic leaf abnormalities. Flowering and fruit development are delayed and abnormal throughout the growing season. Once infected, trees remain hosts for life. Source: PNW Plant Disease Management Handbook
Symptom expression depends on phytoplasma strain, environmental conditions, and plant genotype. Trees infected with more virulent strains show pronounced symptoms including witches' brooms, stunting, and leaf symptoms. Cooler climates may favor expression. Some infected trees enter an asymptomatic carrier state yet remain capable of transmitting the phytoplasma. Source: PNW Plant Disease Management Handbook
Cultural Controls
- Send any trees that may have these symptoms to a diagnostic lab for confirmation of the disease, and never smuggle in budwood or trees.
- Always use certified planting material.
- Reference Seemüller, E., Kiss, E., Sule, S., and Schneider, B. 2010.
- Multiple infection of apple trees by distinct strains of 'Candidatus Phytoplasma mali' and its pathological relevance.
- Phytopathology 100:863-870.