Meyer Lemon Tree Diseases
A cross between a mandarin orange and a lemon, Meyer lemons (Citrus meyerii) suit several outdoor spaces, including terrace and roof gardens. Being small in stature, Meyer lemon a great choice for limited spaces. It grows best in a spot that receives full sunlight, is warm and has well-drained soil. Unfortunately, Meyer lemons are susceptible to a variety of citrus diseases. Early recognition of the worst of these diseases and prompt treatment can potentially stop the disease from spreading or killing your plant.
Frank N. Meyer discovered Meyer lemon trees in China in 1908. When brought to other areas of the world, the trees unwittingly carried citrus tristeza virus without any noticeable symptoms other than trees around them beginning to die back. As a result, in 1950 the Improved Meyer lemon was developed specifically as a sweet, fragrant and disease-resistant plant. The dwarf variety is particularly hardy and works well as an indoor tree.
Common Meyer Disease Types
Common Meyer lemon diseases fall into several basic categories. Viral diseases, like citrus tristeza, may also be deadly to other citrus trees. Mold growth, like sooty mold, covers the plants leaves, fruit and stems, damaging fruit. Rot, like foot rot, harms the lemon's roots. Fungal infections, like greasy spot, may leave the lemons inedible. Bacterial diseases, like citrus blast, may spread by wind. Some citrus diseases are such severe risks to an entire crop that certain states quarantine infected trees or destroy them altogether.
Disease Symptoms and Signs
Different diseases have different symptoms. Citrus tristeza, when it finally manifests, causes root injury, thinning foliage and twig death. Sooty mold looks like a covering of fine black powder. Foot rot causes lesions near the grafted bud union and reduced fruiting. Greasy spot leaves black specks on the fruit’s rind. Citrus blast appears as back spots on the fruit and scabs on the south side of the tree.
A diseased tree is more susceptible to frost, wind and additional insect infestation. Managing some diseases is particularly difficult. Control greasy spot spread by removing and destroying fallen citrus leaves near the infected tree, and treat healthy leaves with copper spray. Antifungal soaps help with mold and fungus, as does maintaining proper drainage around trees. Because sooty mold feeds on honeydew secreted by sap-sucking insects, insecticidal soaps to treat the insect infestation is the first step to control.
Patricia Telesco has been a writer since 1992. She has produced more than 60 books with publishers that include HarperCollins and Simon & Schuster. Her articles have appeared in "Woman's World" and "National Geographic Today." Telesco holds a Bachelor of Arts in English from the University of Buffalo.