Green J-hooks Symptom
  • BBTD is diagnosed by identifying symptoms of diseased plants or by submitting a banana leaf sample for virus testing
  • Green J-hooks are a reliable indicator of banana bunchy top disease (BBTD)
  • To best view this symptom, hold the leaf between your eyes and the sky or sun
  • Green J-hooks are dark green streaks along the veins of a banana leaf with BBTD. These parallel streaks terminate at the leaf midrib with a distinct, J-hooking pattern. Green J-hooks are often associated with "Morse Code"

Green J-hooks and "Morse code"
Green J-hooks and "Morse code" are very reliable indicators of banana bunchy top disease.
Green J-hooks and "Morse code" are relatively subtle symptoms which must be viewed closely. Green J-hooks are best seen by holding a suspected banana leaf between your eyes and the sun; the transmitted light reveals the leaf veins.

Green hooks occur where the flat part of the banana leaf (the blade or lamina) meets the mid rib.

Green J-hooks curve down to midrib 

"Morse code" and green J-hooks

Green J-hooks, "Morse code" in leaf

Green J-hooks on leaf veins, "Morse code" on the leaf midrib

Photographs are courtesy of the University of Hawaii and the Hawaii Department of Agriculture

Maintained by Scot Nelson:
Last Revised on September 12, 2006