Dragon Fruit Canker
Neoscytalidium dimidiatum
The most damaging disease of dragon fruit (pitaya) in warm, humid regions, a fungus that scars the fleshy stems (cladodes) and fruit with spreading sunken cankers. It is mostly cosmetic on the plant at first, but it can ruin fruit for market and weaken heavily infected stems.
🔎 How to spot it
Symptoms start on the cladodes as small sunken chlorotic spots, sometimes with a tiny orange center, that enlarge into convex orange to reddish-brown spots ringed by yellow halos or dark, water-soaked tissue. The spots bear tiny black fruiting bodies (pycnidia) packed with spores, and old lesions dry, crack, and perforate the stem into shot-hole patterns. On fruit, whitish-yellow sunken spots merge into brown dry lesions that crack the peel.
🥀 Damage it causes
On the plant the cankers are mostly cosmetic at first but can coalesce, dry out, and weaken badly infected stems. The real loss is on the fruit, where the blemishes alone can cut market value by 60 to 80 percent or more, and the cracked peel opens the door to other post-harvest rots.
🔬 What causes it
The fungus Neoscytalidium dimidiatum. Its spores spread when splashed by overhead irrigation or windblown rain onto young cladodes, flower calyxes, and developing fruit, and it is readily carried on infected cuttings. Warm, wet, humid conditions favor it, and half of its spores can germinate within a day once temperatures rise above about 72 F.
🛡️ Prevent it
Start with clean, disease-free cuttings and keep groves open and airy. Water at the base rather than overhead to keep cladodes dry, and time any major pruning and sanitation for the cool, dry season. Remove and destroy infected cladodes and fruit rather than letting them sit in the planting.
🧯 If it is already here
There is no cure for an infected cladode, so cut out and destroy diseased stems and fruit to lower the spore load, opening the canopy for airflow and spray coverage. Protectant fungicides such as copper and azoxystrobin, rotated among groups, help shield healthy growth in wet weather, but sanitation is the backbone of control.
💡 Good to know
Because the blemish is mostly skin-deep, lightly spotted fruit is still fine to eat even though it will not sell; the disease is about appearance and spread, not toxicity. Keeping the planting open and dry does more than any spray.
🌱 Plants it affects
2 plants in the library can be affected by this problem
For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.