Lesions are initially tiny translucent areas which later turn tan and have a chlorotic halo. Sometimes a reddish-purple pigment is associated with leaf spot of variegated Polyscias balfouriana . Control - Alternaria leaf spot can be controlled with elimination of overhead irrigation and exposure to rainfall. In addition, use of greater than recommended levels of fertilizer result in reduced severity of Alternaria leaf spot on several other members of this plant family including schefflera, dwarf schefflera and false aralia. Symptoms - Pythium root rot of many foliage plants is most often caused by P. splendens .
Plants appear stunted, chlorotic and wilted even when soil moisture is high.
Roots are usually rotted, brown to black and mushy. Since these symptoms can be caused by many different soil-borne pathogens, a precise diagnosis can only be made when the roots are culture indexed for these organisms. Grow plants on raised benches away from the native soil, since it can be a source of infection or can become contaminated and infect future crops. Soil drench applications of several fungicides are effective in controlling Pythium root rot. Symptoms - Aerial blight can begin as discrete lesions anywhere on plant foliage.