One may diagnose banana bunchy top more accurately by observing the more subtle disease symptoms associated with leaf veins (Morse code, green J-hooks) and petioles (mottling), rather than the "bunchy" appearance of leaves, which can have other causes (i.e., nutrient deficiency, herbicide injury).
You can watch our video at youtube about the banana bunchy top disease if you want to learn more about recognizing the subtle symptoms on leaves:
Part 1:
Part 2:
You may also visit my banana bunchy top website for more photos and information:
Banana Bunchy Top Disease in Hawaii: Symptoms, Diagnosis and Management
Scot