Banana streak is a viral disease caused by a complex of banana streak viruses (BSV) species. BSV species have been reported in many banana-producing countries. Infections are characterized by discontinuous chlorotic areas that turn into necrotic streaks on leaves and a split pseudostem. A severe form in which the pseudostem develops heart rot eventually leads to the death of the plant.
The disease was first reported in Côte d'Ivoire in 1966. The impact of the disease varies greatly; from serious in certain localities, to confined to a few plants and not considered important in others.
The presence of species of the virus integrated in the DNA of banana cultivars that have a copy of the so-called B genome inherited from their Musa balbisiana parent, imposes restrictions to the movement of these cultivars.
Symptoms range from an inconspicuous flecking to lethal necrosis depending on the virus/isolate, the cultivar and the environment. The most common symptoms are narrow, discontinuous and sometimes continuous chlorotic or yellow streaks that run from the leaf midrib to the margin. Spindle or eye-shaped patterns as well as yellow blotches have also been observed. The streaks eventually turn orange and often brown or black. Necrosis has also been observed on the midrib and petiole. Necroses occur mostly under low temperature, short-day conditions.
The accidental pathogen, page 14 in the 2004 INIBAP Annual Report