December 2009. Symptoms of raised, circular lesions (rusty brown/red) have been observed on Dragonfruit (Hylocereus sp.) stems from northern Queensland, Australia. Numerous attempts at isolating the primary cause, either fungal or bacterial, have been unsuccessful.

It was suggested that excessive watering might be causing the condition, known as scab. Links to two websites were provided:

http://www.wildflower.org/expert/show.php?id=2421
http://www.cactusmuseum.com/diseases.asp