Citrus greening disease is a serious bacterial infection that affects citrus trees. It was first detected by the USDA in 2005 and has continued to spread in Florida. This disease slowly kills trees while causing them to produce green and bitter fruits. Recently, researchers at the University of Florida released more information on the problem. They discovered that the insect spreading the infection, the Asian citrus psyllid, is migrating from abandoned groves to other areas. The greening disease threatens the entire citrus industry in Florida.
Citrus greening disease, also called huanglongbing or yellow dragon disease, is caused by the Liberobacter bacteria. Although the bacteria cannot harm humans, they are lethal to citrus trees. The Asian citrus psyllid, a small and winged insect, spreads the bacteria by feeding on the trees. A recent study by the University of Florida revealed that the current economic recession has created more abandoned groves and feeding grounds for the psyllids. Moreover, the psyllids are flying to other groves and infecting new trees.
The initial symptoms of citrus greening disease are not easy to recognize. First, leaves and shoots turn yellow. Mottling also appears. During the first stages, the problems are often misdiagnosed as zinc deficiency. The trees produce green, lopsided, bitter and inedible fruits. Then, tree limbs begin to die, and ultimately the entire tree is killed. The entire process may take from 2 to 10 years. There is no cure.
The impact of citrus greening disease is enormous. It threatens Florida’s $9.3 billion citrus industry and 76,000 workers. Florida has 620,000 acres dedicated to this industry, but it is estimated that 140,000 acres are abandoned. The abandoned groves pose a serious threat by allowing psyllids to breed and spread the infection. The disease currently affects 32 counties in Florida. In 2010, the USDA announced a plant quarantine to prevent the spread of the disease. It has not been successful in curbing the dispersion of the problem in Florida.
The future of citrus greening disease is uncertain. Currently, quarantines are in effect. The USDA has created an entire site dedicated to this issue. The Division of Plant Industry has also established a hotline for growers. They are encouraged to identify and report infected trees. The affected plants are treated with insecticides and often have to be destroyed. Scientists are exploring disease resistant varieties and new insecticides. In addition, they are researching the potential for predators and parasites to destroy the psyllids. Although the fight to eradicate citrus greening disease is not over, researchers are hopeful.