Morphological Changes Induced by Phytoplasma In Citrus aurantifolia

Witch’s Broom is a serious disease caused by phytoplasma that infects several crop species including citrus. Witch’s Broom disease of lime (WBDL) induces changes in plant morphology such as clustered branching and leaf rosette, perhaps caused by lost apical dominance. This study characterized the vegetative morphological changes induced by WBDL. Stems (50 cm long) were collected from infected trees at various stages of infection during the spring of 2009 and the fall of 2010. Data on leaf number, leaf area, number of branches, and stem length were taken at 10 cm stem segments. The data showed branch and leaf clustering was higher in the fall than the spring for symptomless, transitional and symptomatic branches. Marked differences in leaf and stem morphology at three distances from the stem apex, i.e. 10, 20-30, and 40-50 cm. This information will help in the understanding the effects of phytoplasma on the stem and leaf morphology of citrus aurantifolia.