Streaks on leaves

Variegation

Cause: A genetic abnormality that occurs in tissue-cultured plants. 

Solution: Destroy affected plants and set additional following suckers on neighbouring plants. 

Banana streak virus

Cause: The banana streak virus (BSV). The pale streaks or flecks on the leaves become darker with age. Symptoms of cucumber mosaic virus are similar.

Solution: Eradicate infected plants and set additional following suckers on neighbouring plants. Do not take planting material from infected plants.

Zinc deficiency in young tissue culture plants.

Zinc deficiency

Cause: Insufficient zinc available to the plant. 

Solution: First confirm the diagnosis with a leaf analysis test. Apply zinc fertiliser at the rate recommended on your analysis result. 

Note dark green flecks develop along the veins of the leaves, producing a ‘dot-dash’ pattern which ‘hooks’ into the midrib from the leaf blade.

Bunchy top

Cause: The banana bunchy top virus (BBTV) which is spread in infected planting material and by the banana aphid, Pentalonia nigronervosa. BBTV is not present in tropical Australia, and movement of planting material is controlled by legislation. 

Solution: There is no cure for this disease and all infected plants must be eradicated. Outbreaks must be reported to your state primary industry authority.  

More info:

Cucumber mosaic virus

Cause: Cucumber mosaic virus (CMV). This virus has a wide host range and can be spread to bananas by aphids. 

Solution: Disease incidence is sporadic and generally low. Control measures are not warranted. Do not take planting material from infected plants.

October to November streak

Cause: A physiological disorder of unknown cause which generally occurs during October and November. 

Solution: There is no known cure. Plants will grow out of it. 

Chlorotic patching

Cause: A physiological disorder that indicates the plant is suffering stress. It usually occurs in spring and can be related to water-logging.

Solution: Determine the exact cause of plant stress. Check for corm or root damage from banana weevil borer or nematodes.