However, as a native to Mexico they can struggle to survive as a houseplant as it can be difficult to provide the right environmental conditions. Botrytis is the primary disease affecting poinsettia stems, leaves and bracts at all stages of production. & Ruehle (46,60). Identifying Poinsettia Nutritional Disorders By Brian Whipker, Ingram McCall and Jared Barnes To view tables and figures, click on the PDF link to the right. Plant fertilization requirements, nutrient monitoring and nutrient disorders have been a major research and … Xanthomanas leaf spot on poinsettias begins with dull gray water soaked areas. Xanthomonas leaf spot on Poinsettias Symptoms of Xanthomonas campestris pv poinsettiicola begin with dull gray water-soaked areas. Whitefly . Phytophthora and Rhizoctonia can also rot the roots of poinsettias, and under favorable conditions, move upward to affect the stem and lower branches. Poinsettia Insect & Mite Management A wide variety of insect and mite pests have been found in association with poinsettia production both in shade houses and in the greenhouse ( Table 1 ). Each of the six Christmas cactus species produces a different colored bloom, with red being the most common. In the realm of insects and diseases, two of the most common poinsettia problems for growers are whitefly and Botrytis. Beware: The Alternaria spp. These pests can feed on many parts of the poinsettia plant or be associated with the production areas. Poinsettia pests and diseases Purchasing a pot grown Poinsettia is as much a part of modern Christmas celebrations as it is to buy a trimmed fir tree. Yellow or tan spots can develop across the leaf. Until recently, it has been known to be a production problem only for poinsettias in Florida and Hawaii, where inoculum presumably survives from … Beware of this disease next year during poinsettia propagation season. As the disease progresses, spots turn brown and angular and can be confused with poinsettia scab. As with all cacti and succulents, the Christmas cactus is susceptible to disease. that spot leaves will also infect bracts. Alternaria leaf spot is one of several fungal diseases that can pounce on your poinsettias when your attention is diverted.The pathogen, Alternaria euphorbiicola (or certain other Alternaria species) most likely travels along with poinsettia cuttings, and attacks when the environmental conditions favor infection. Yellow or tan spots can develop across the leaf. So, it's a good idea to send samples to … When poinsettia season comes, that also means the arrival of pests and diseases that affect the popular holiday crop. Poinsettia scab is a spot anthracnose disease caused by the fungus Sphaceloma poinsettiae Jenk. As the disease progresses, spots turn brown and angular so could be confused with poinsettia scab. A well-cared-for poinsettia can live for up to two years. A festive houseplant during the winter holiday season, the poinsettia (Euphorbia pulcherrima) grows in U.S. Department of Agriculture plant hardiness zones 9 through 11. Schlumbergera, commonly referred to as Christmas cactus, derives its common name from its winter bloom period. However, poinsettias are susceptible to several diseases, mostly fungal and include root rot, root and stem rot, black root rot, scab, powdery mildew and blight. Pathogens Root rot caused by Pythium is the most common disease affecting poinsettia production. & Ruehle (46,60). Photos: Jim Barrett.