Phyllosticta pad spot likely got to this prickly pear.
Q: One of my prickly pears became riddled with black splotches. The attached photo is of a typical pad but there are many pads at the bottom of my trash bin that were worse. I know about balances in nature and the benefits of coexistence, but this plant was an eyesore and had to go. I think the problem is caused by a fungus. I want to replace it with an Engelmann’s prickly pear. It also looks like a rodent chewed the outer edges of some of the pads. Can you ID the fungus if it is a fungus? How persistent is it in the soil? If it is persistent can I treat the soil with a fungicide so the new prickly pear doesn’t get the fungus? Is the chewing damage more likely to have been done by a packrat or a Harris’ rock squirrel (we have both)?
A: Several pests or conditions may cause lesions on prickly pear but the most common is known as Phyllosticta pad spot and it is persistent in our area. I am afraid that no amount of fungicide would take care of this since it is endemic to the desert and very common. It spreads by releasing spores that are transported by rain and wind, and is difficult to manage. Severely infected pads or plants should be removed from your landscape as you are already doing. That’s about all you can do. The chewing damage could have been done by any of the resident rodents or javelinas if you have them as well.
