It is bacteria which are also hosted by local chaparral. You can control it with a copper pesticide such as Liqui-Cop.

Thanks Hermitian. Have you already tried it successfully? I got information earlier from a Spanish forum, specifying that the âÂÂfish eyeâ disease is caused by the Dothiorella fungus, while the yellowish stains on the red pitaya are caused by the Erwinia bacteria and are impossible to cure. I had to get rid of the red pitaya and will treat the yellow one with copper oxychloride, as Liqui-Cop is not available here. If it doesnâÂÂt work, IâÂÂll try with citrus seeds extract but I have no idea about dosing this extract.

Jalilu