Dragon Fruit Stem Rot is caused by either a bacterium or a fungus infection of the dragon fruit plant.
Depending on the cause of the rot, whether it is a bacteria or fungus, it can appear as yellowing and rotting of the stem and blades, caused by the Xanthomonas campestris and Erwinia carotovora bacteria, or the Colletotrichum gloeosporioides fungi.
Anthracnose disease on dragon fruit was characterized with reddish- brown lesions with the lesion centres becoming white and chlorotic haloes symptoms on stem.
Pruning. Prune and destroy or bury infected leaves, twigs, and branches during fall or winter.
To stimulate vigorous growth of severely infected trees, fertilize after the leaves open and spring rains have stopped. Avoid irrigation systems that wet leaves.
Prune during winter to increase air circulation in the canopy and remove the previous season’s dead and diseased twigs and branches.
When planting, space the plants far enough apart to maximize air circulation and increase sunlight, both of which facilitate faster drying of leaf surfaces when trees are fully grown.
Treatment is often a copper fungicide, mancozeb and metalaxyl sprays. Spraying one of each chemical at weekly intervals. and pruning out the infected parts of the plant.