helix (English Ivy) as well as other plants in the family Araliaceae
are susceptible to a bacterial disease called Xanthomonas leaf spot
(Xanthomonas campestris pv. Hederae).
English Ivy symptoms begins as circular to irregularly shaped, black,
necrotic lesions. (Fig. 1 and 2)
the infection progresses, lesions grow together, or coalesce (Fig
3), giving the plants a blighted appearance (Fig 4). The disease is
not considered systemic in English ivy.
manage the disease:
Destroy severely symptomatic plants and debris
Nutritional studies of schefflera have indicated that applications
of higher than recommended rates of fertilizer produced increased
resistance to Xanthomonas leaf spot. As the fertilizer level increased
from the recommended level (5 g of Osmocote 19-6-12 per 15 cm
pot in 3 months) to five times that rate, the number of lesions
per plant decreased linearly. Plant growth was not adversely affected.
Apply chemicals, at 14 day intervals , such as
Chase, A.R., ‘Compendium of Ornamental Foliage Plant Diseases’.
APS Press, 1987. pp. 60-61