Banana Bract Mosaic Virus
The most obvious symptom appears on the bracts of the inflorescence as a reddish-brown mosaic pattern. Bracts are the name for the small leaves that cover the rows of flowers on the flower stalk. In young plants, chlorotic or red-brown spindle-shaped lesions and streaks can be found on leaf petioles or midribs. Occasionally, they also appear on the blade running parallel to the veins or on the stem of fruit bunches. When the dead leaves are pulled off, dark brown blemishes or streaks are visible on the internal tissue. Growth defects on bunches and deformed fruits are also characteristic of the disease. The virus can spread quickly and severe infection can lead to losses in fruit yield and quality.
The symptoms are caused by a virus that affects banana trees at different growth stages. It is transmitted in a non-persistent manner by several species of aphids. The virus, acquired while feeding on infected plants, only survives for a short period in the vector. The transfer or transport of infected plant material between fields is another way of transmission. Its common name comes from the characteristic mosaic symptoms on the flower bracts.
The bio-control fungal agent verticillium lecanii can be used to reduce populations of aphids. Insecticidal soap can also be used to control aphids when their numbers are not too high.
Always consider an integrated approach with preventive measures together with biological treatments if available. There is in no direct chemical treatment of viral diseases. However, the use of pesticides can control aphid populations up to a certain degree (for example cypermethrin, acetamid, chlorpyrifos) Herbicides can be used to kill affected plants or young shoots growing from severed trees.