Stem canker (dragon fruit)
Orange-to-brown sunken cankers on the fleshy stems that enlarge, crack and rot the plant тАФ clean cuttings, airflow and dry stems are the main defences.
- Pathogen
- Neoscytalidium dimidiatum (fungus)
- Attacks
- Fleshy stems; also blemishes fruit
- Favoured by
- Warm, humid, overcast weather; wet stems
- Best defence
- Clean cuttings, airflow, prompt removal
Overview
Stem canker, caused by the fungus Neoscytalidium dimidiatum, is the single most important disease of dragon fruit worldwide. It attacks the fleshy green stems, starting as small orange-to-brown sunken spots that enlarge into cankers, crack into scabby lesions, and in bad cases rot and kill whole stem sections; the same fungus can blemish the fruit skin and downgrade the crop.
It spreads fastest in warm, humid, overcast weather and by splashing water, and it is readily carried on infected cuttings тАФ so planting clean material and keeping the plant dry and well-ventilated matter far more than any single spray. Because the crop is a long-lived perennial, letting canker build up on the framework stems is a lasting problem, so prompt removal of affected tissue is central.
How to identify it
- Small orange-to-brown sunken spots on the fleshy stems that enlarge into cankers.
- Cankers crack into rough, scabby lesions; badly affected stem sections rot and die.
- Spots and blemishes can also appear on the fruit skin, downgrading the produce.
- Worst in warm, humid, overcast spells and where stems are frequently wet.
The damage it does
- Rots and kills framework stems the plant crops from, cutting yield for years on a perennial planting.
- Blemishes the fruit skin, lowering its market grade.
- Builds up and carries over on a long-lived plant if affected tissue is left in place.
When to act
- Act at the first sunken spots, before they enlarge into cankers and spread along the stem.
- Step up watch and protective sprays going into warm, humid, overcast weather.
- Never take cuttings from an affected plant тАФ the fungus travels on the planting material.
Organic & cultural control
- Plant only clean, disease-free rooted cuttings from a healthy mother plant.
- Keep good airflow between poles and avoid wetting the stems (drip, not overhead irrigation).
- Cut out and destroy affected stem sections well below the visible canker, and dispose of them off-site.
- Keep the base clear and dry тАФ dense weeds against the stems trap humidity and worsen canker.
Chemical control
- A protective copper- or mancozeb-based spray at first sign, repeated through humid weather.
- Treat cut surfaces after removing cankered tissue to stop re-entry.
- Confirm the current recommendation and dose with your local KVK or horticulture department.
Crops most at risk
Where this problem is called out in our crop guides тАФ open a crop for the full package of practices.
Frequently asked questions
Why does stem canker keep coming back on my dragon fruit?
Usually because affected tissue or infected cuttings keep the fungus in the planting, and because warm, humid, wet-stem conditions keep favouring it. Cut out and destroy cankered stem sections well below the lesion, plant only clean cuttings, keep airflow up and the stems dry, and spray protectively going into humid weather тАФ sanitation and a dry, airy plant matter more than spraying alone.
Can I take cuttings from a plant that has had stem canker?
No тАФ the fungus travels readily on cuttings, so taking planting material from an affected plant carries the disease straight into the new planting. Take cuttings only from clean, healthy mother plants with no sign of canker.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.