Curled or distorted leaves
Spike leaf
Cause: A temporary shortage of calcium caused by rapid growth. Most common in spring and early summer.
Solution: Avoid sudden bursts of growth by using regular, light fertiliser applications. A foliar application of calcium nitrate at 10 g/L in early spring will reduce the problem.
2,4-D damage
Cause: Spray drift of 2,4-D onto green parts of the plant.
Solution: Take efforts to avoid spray drift onto leaves. Plants should grow out of it.
Tissue-cultured off-type
Cause: A genetic abnormality that occurs in tissue-cultured plants.
Solution: Destroy affected plants and set additional following suckers on nearby plants.
Banana streak virus
Cause: The banana streak virus (BSV). The streaks or flecks on leaves become progressively darker with age and the leaves may die. Symptom expression is sporadic. Symptoms of cucumber mosaic are similar.