of the plant will become flaccid, and adventitious roots may appear on the stem of the plant. the vascular system exhibits a progressively darker brown color as the disease progresses, in addition to possible lesions on the stem. management practices are similar to those of potato. banana ralstonia solanacearum on an overripe banana commonly known as moko disease, after a banana variety from trinidad that went extinct in the 1890s. typically, yellowing and wilting of older leaves occurs, as well as reduced fruit size and eventual rotting of the fruit. in addition, flowers can become blackened and shriveled, and the vascular tissue discolored. exclusion of the disease where it is not present is the only effective means of control. if an area does become infected, all of the infected plants must be eliminated, which is why strong sanitation practices must be used to reduce the spread of disease. importance ralstonia solanacearum is classified as one of the world's most important phytopathogenic bacteria due to its lethality, persistence, wide host range, and broad geographic distribution. although the pathogen causes major yield losses in the tropics and subtropics, it is currently a continuing threat in temperate climates. ralstonia solanacearum is a high-profile alien plant pathogen of a2 quarantine status affecting a very wide range of crops. this means that it is present in parts of europe, but is under statutory control. worldwide, the most important crops affected are: potato, tomato, tobacco, banana, and geranium. in the uk and the rest of the eu, the most important crops affected are potato and tomato. it would cause serious economic damage were it to become more established than it currently is. losses are due to actual yield reduction and also due to statutory measures taken to eliminate the disease. bacterial wilt caused by r. solanacearum is of economic importance because it infects over 250 plant species in over 50 families. as of 2007, this pathogen has affected over 450 host species representing 54 plant families due to its broad host range around the world. the disease is known as southern wilt, bacterial wilt, and brown rot of potato. many more dicots suffer from the disease than do monocots. among the monocot hosts, the order zingiberales dominates, with five of nine families being infected by this bacterium. the reason why some families are more susceptible to bacterial wilt is still unknown. originally, r. solanacearum is found in tropical, subtropical, and warm, temperate climates, but is not believed to survive cold temperatures. however, this pathogen has recently been detected in geraniums (pelargonium spp.) in wisconsin, usa and was traced back to the import of geranium cuttings to north america and europe from the highland tropics where race 3 biovar 2 is endemic brown rot of potato caused by r. solanacearum race 3 biovar 2 is among the most serious disease of potato worldwide, and is responsible for an estimated $950 million in losses each year. race 3 biovar 2 is cold tolerant and classified as a quarantine pathogen. in addition, this race/biovar has been listed as a select agent in the agricultural bioterrorism act of 2002, and is considered to have potential to be developed as a bioterror weapon.