Witches' broom disease is sweeping through more than 60 percent of the longan-growing area in the Cuu Long (Mekong) Delta, leaving many farmers with severe losses, according to the Plant Protection Department. The disease appeared in Viet Nam in 2003 from infected longan (Dimocarpus longan) strains imported from neighbouring countries, according to experts. There are no effective measures to prevent or control the disease.
Comment: The news has been published via International Society of Infectious Diseases. For some plant diseases only very few data is available on the extent of the disease, on its biology and epidemiology. Since witches' broom symptoms can apear on differnet fruit species of Prunus, Malus and other fruit trees in other parts of the world, also information on their control should be searched there. The causal agent is phytoplasma, which can be determined only in lab diagnostic procedure. In general the spread of the disease is possible by care for healthy planting material and control of insect vectors. Many new findings have become available in recent years about the transmission and epidemiology of phytoplasma diseases.