Plant Diseases

Plant diseases threaten all ecosystems as other organisms are dependent on plants for food or habitats.The oak, Quercus robur, can live for centuries and is a habitat for about 300 different types of insects and 300 different types of lichens. A disease that spread from Europe causes acute oak decline as a dark fluid oozes from the bark. Scientists still do not know the cause of the disease that causes the rapid decline and often death of the tree.There is evidence so far of previously unknown bacteria in the tree and oak jewel beetle has been found in infected trees. It may be that the oak jewel beetle acts as a vector but more research involving DNA analysis of all the organisms found on both infected and uninfected trees is needed for comparison.Plant diseases threaten food security. In many places people do not get enough to eat. Bananas are the fourth most important cash crop in the developing world. Plantains (a type of banana) also form the staple food for many people. In recent years black sigatoka has caused a 40% drop in yields. Most of the bananas traded internationally are the Cavendish variety, all from the same clone.