What is Citrus Greening Disease?
Plants affected by citrus greening disease, also known as huanglongbing or yellow dragon disease, have acquired a serious bacterial infection. Citrus greening disease symptoms vary widely but include new leaves that emerge small with yellow mottling or blotching, yellow shoots, enlarged and corky leaf veins, as well as fruits that are small with green ends and filled with small, dark, aborted seeds and bitter juice. This bacterium is transmitted by the Asian citrus psyllid, a tiny, wedge-shaped insect with brown and white mottled coloration. Although small, this pest has citrus growers across America fearful for the future of the entire industry. If you see it in your backyard citrus trees, you should capture the bug and call your local extension service right away.
Control of Citrus Greening
There is no cure for citrus greening, which explains why spotting citrus greening disease symptoms early is so crucial– rapid removal of infected trees is the only way to stop the spread of the bacteria responsible. Since infected trees will never again produce useful fruits, they only serve as a reservoir for this economically dangerous disease. Plants affected by citrus greening include all the common citrus fruit trees, like oranges, limes, and lemons as well as ornamentals like orange jasmine, jackfruit, and limeberry. Orange jasmine has been implicated in Florida as a means of transportation between nurseries for Asian citrus psyllids, since it is a favorite of this pest. You may be able to prevent citrus greening by erecting a screen house around known, disease-free citrus trees, but psyllids are small, often no more than 1/8 inch (3 mm.) long, so your screen must be tightly woven. Insecticides can be highly toxic to the bees that pollinate citrus, but if you live in one of the many citrus greening quarantine zones, it may be useful to treat your citrus tree’s leaves with chlorantraniliprole, spinetoram, dimethoate, or formetanate.
