Treat your poinsettia well throughout the holiday season. Pythium root and stem rot is a common disease problem in poinsettias, and is often difficult to control. Molybdenum deficiencies can cause distorted leaves due to the failure of the interveinal areas to expand normally. Large roots and lower stem may be enlarged and ridged. Mechanically transmitted. Poinsettias are susceptible to a wide variety of diseases that attack the The disease causes a whitish, powdery discoloration of the upper and lowers surfaces of the leaves and colored bracts (Benson et al. Molybdenum deficiencies can cause distorted leaves due to the failure of the interveinal areas to expand normally. Poinsettias are also susceptible to Rhizopus soft rot (Rhizopus stolonifera). When purchasing plants, carefully check for whiteflies and other insects. View our privacy policy. High pH. When the soil becomes dry to the touch, water the plant until water begins to flow out the bottom of the pot. Disinfest tools. In addition to biotic agents, improper fertilization practices can cause symptoms in poinsettias. Apply a fungicide to protect plants as soon as any mildew is found. Botrytis may also cause stem blight (Figure 9) on cuttings and plants, often at branch crotches. Apply a fungicide to protect plants. Do not wet the foliage when irrigating. Bract edge burn may cause serious problems in the final weeks of production or following boxing and transport. Hey, it's the holiday season! Box 1106 New Haven, CT 06504-1106. Miscellaneous diseases and disorders; Bleaching necrosis: Air pollutant injury from either chlorides (> 0.5 ppm), nitrogen dioxide (> 2-3 ppm) or sulfur dioxide (> 0.5 ppm) : Bract necrosis: Physiological disorder favored by high humidity, heavy watering and high (ammoniacal) … Managing Pests and Disease. Further, leftover solution in the spray tank can cause trouble in the BCA areas when the tank is used again, and other chemistries are added that are not compatible. Symptoms . By watching for potential problems, understanding their causes andknowing the proper corrective actions to take, one can avoid most of theseissues. They're synonymous with Christmas, all around the world, and make fantastic festive decorations both inside and outside the home. Poinsettias need bright, but filtered light, away from strong sun and draughts. Diseases of Poinsettias. Over-watering will cause the lower leaves to turn yellow and drop. They can be found either on the plant or soil surface. In continuous feed programs, 10% of the soluble fertilizer applied should leach out the bottom or clear tap water should be applied every second or third watering. Favored by excess moisture and overcrowding of plants. This is why scouting might be more important in this crop than any other.. Here’s a month by month guide on what you should be looking for to prevent small problems from becoming big issues. Apply a fungicide to protect plants. Be nice to your plants! Lower leaves yellow and fall. Several diseases affect production of poinsettia, including foliar diseases such as Botrytis gray mold, powdery mildew, Alternaria blight, Xanthomonas blight, Erwinia blight, Phytophthora blight, and root diseases such as Pythium, Phytophthora and Rhizoctonia root rot. In some people, it can cause skin rash, eye irritation, and irritation or burns to the mouth. Plant wilt. Water should be able to drain from the bottom of containers. Grow at higher temperatures. Don't put poinsettias in cold, drafty, or hot places. Stems often decay quickly, starting with the formation of brown to reddish brown lesions that enlarge, forming sunken cankers near the soil line …