Narrow distribution. Philippines and Oceania. Fungal disease; possibly serious, but little researched.
Spots, round to irregular, grey-brown, with yellow halo on mature leaves. A wet weather disease; spores spread by wind and rain from underside of leaves.
Cultural control: difficult as plants harvested at different times and replanted in same place. Remove infected leaves and burn them to delay onset of disease during wet times; practice crop rotation, and plant 'gardens' at one time.
Chemical control: not appropriate – uneconomic, and potential to contaminate fresh water lens.