used on banana trees in order to protect them from primary inocula. The fungicide does not kill the pathogen itself, but works on the pre-necrotic spots on the leaves, stopping the secondary spores from inoculating new, healthy plant tissue. The best time to apply this protective fungicide is in the beginning of the season in order to stop any initial infection. The class of fungicides widely used to control black leaf streak is the triazoles. These are demethylation inhibitors and should be rotated with compounds having other modes of action to slow the development of resistance. Leaves that have already been infected must be removed mechanically to save the rest of the tree. Research has shown that there may be fungicide resistance developing for M. fijiensis. It has been observed that following the intensive application of chemicals, the fungus persisted and spread. The same observations were found in fields with no chemical interference; the belief now being that the untreated fields are “breeding grounds for (the) development of resistant strains”. Methyl benzimidazole carbamates are also used and there is also resistance known to these. Although fitness penalties are common in resistance evolution many MBC resistant pathogens do not suffer any penalty and a few have the opposite effect. M. fijiensis is one such case: Romero et al., 1998 find MBC resistant isolates benefit from enhanced virulence (specifically tested with benomyl). Research today shows continuous action towards reinventing banana breeding programs. However, some cultivars of bananas are resistant to the disease. Research is done to improve productivity and fruit properties of these cultivars. A genetically modified banana variety made more resistant to the fungus was developed and was field tested in Uganda in the late 2000s. Furthermore, the search for genetic resistance shows promise with the discovery of a protein that can produce a hypersensitive response to control M. fijiensis that is being introduced into banana trees. This may lead to the identification of a resistance gene that could be transferred to banana trees. Importance The worldwide spread of the disease has been rapid, with its naming and first reported occurrence in 1963. The disease was reported in 1972 in Honduras, from where it spread north to central Mexico and south to Brazil and into the Caribbean islands in 1991. The fungus arrived in Zambia in 1973 and spread to the banana-producing areas of Africa from that introduction. The first occurrence