One major disease of banana is bunchy top. It is viral disease spread by an aphid. Affected plants will survive for many years like this. If the big plants get infected, the bunch will not mature.
Bunchy top spreads and causes heavy loss once it enters the garden. The virus cannot survive in the soil. It multiplies in the entire plant in the sap. It spreads with the sickle and other implements also. Kerla, turmeric, ginger and cardamom are the alternate host plants of the virus. There is no medicine for the control of bunchy top disease and no variety is resistant against the bunchy top disease virus.
Control method
Selecting sucker from disease free garden and uprooting and destroying the plant housing the disease symptoms immediately. Spray the insecticide for the control of the vector effect. Avoiding alternate host plants is important.
Bunchy top disease is a major worldwide disease and prevention is the only solution.