Dragon fruit black sooty mold help

[MorroBay]

I got this weird black mold around the spines of my dragon fruit.  Any ideas?

[John B]

You have a pic? Is it on the cactus or the fruit? Ants farm that stuff so I'd check there. I used to get them on the tips and crevices of the fruit when ants were farming insects. I just blast it off.

[MorroBay]

On the cactus.  Clustered on the spines. 

[John B]

Could be the humidity and favorable conditions upon contamination (dirty pruners). Just double check you don't have any ants spreading it between aphids. If you think it's getting worse, just use copper. It'll clear it off.

It looks like you may be spraying the whole cactus down. If so, you may want to stop that.

[spaugh]

its from the humidity and temperature.  my dragonfruit plants in the greenhouse get it a little during winter here. I dont think its anything to worry about.

[MorroBay]

Alright, I’ll not worry.  It did kill a few new growths but that happens.  I did a quick spray with copper.  I get tons of fog and moisture here a few hundred feet from the beach.  Just wanted to make sure I identified the issue and I wasn’t missing a growing problem.