Examination of the lower leaf surface generally reveals sporodochia which are irregularly shaped, black and have a white fringe of mycelia. Control - Avoid temperatures between 60 and 85 F when possible, minimize wounding, and fertilize plants at recommended levels. Root and stem tissues become water-soaked necrotic and collapse. On larger plants wilting, yellowing and stunting can be signs of Phytophthora crown and root rot. Overwatering will make Phytophthora crown and root rot more severe and use of appropriate fertilizer levels is critical.
Lesions are tan to black, dry and shrunken.
When lesions encompass the entire stem the seedling wilts and dies. Larger plants rarely seem affected by this disease and apparently can outgrow an early infection. Control - Chemical control of diseases caused by Rhizoctonia has been investigated on many plants using a wide variety of fungicides. Mealybug, mite, and scale infestations are typically the result of bringing infested plant material into the greenhouse. Aphids, moths, fungus gnats and thrips have the ability to fly and thus invade the greenhouse from weeds and other infested plants outside.