I have some old, very large cacti 5' x 4' beds of cacti that have been on my property for many years. They are the type with the Purple/pink prickly pears on them. In the last month one had gotten mold on most of it wear the needles come out and now it has spread to all of the cacti all different areas of the outside of the house. there are several cactus plants 3 acres away and don't have any mold on them. They seem weak and not as sturdy as they used to be. We are in Texas were it is extreme drought conditions. I squirted them with the water hose yesterday to see if the mold would come off and it did, but some of the prickly pears and actual cacti broke off with the force of the water which wasn't very hard at all. Some parts of the bed or near the ground are turning black and look like they are rotting. Please help. Do I need to cut them down or is there something I can put on them?
Are you sure it's mold and not Cochineal scale? Cochineal are attracted to cacti in the type of conditions you describe, and they certainly have the effect you're describing. You'll be able to tell by scraping some of it off and smushing it - mold will stay the same, and Cochineal scale will turn red. If it's truly mold, you can treat it with a solution of 10% milk in water and into that about 5% copper (II) sulfate. If it's scale, something more in the order of neem oil is indicated. Scale is notoriously difficult to kill.
Thank you for responding, I did find out on the internet and saw a picture of the Cochineal scale and that is what it is . I think it is so far gone now, the pads are weak and are falling off and so are the pears. Neem oil is what you suggests. Where can I find that? Is it easy to find?
It should be at your local garden store; if the staff there are at all knowledgable, you can ask them about their preferred remedy for Cochineal on prickly pears. Neem is my fave, because it actually smothers the little nasties.
Thank you very much. Not sure if they will know what it is, but will ask. I have asked some of the old timers around this area and they had no idea what it was either.
