White fungus or disease on desert plants (Tucson, Pima: house, landscaping)

[Jukesgrrl]

I've searched the boards but haven't found a thread related to this issue. In the past few weeks, several of the plants in my desert landscaping, notably a prickly pear cactus (opuntia) but others too, have developed a white growth. From afar, it looks like someone splashed bright white paint on the plant. Close up, it appears to be a fungus-like thing resembling flecks of white cotton.

On two of the plants (sorry, they were here before I was, so I don't know their name) it went away by itself and just this week it reappeared on one of the two. This weekend, the thing appeared on one of the three (now quite large) pear cactus the developer planted along the west side of the house.

About two miles from where I live I noticed a grouping of pear cactus along the roadside that is covered with the stuff and the plants look diseased. Mine currently appear to be healthy aside from the flecks of white stuff.

I've lived in this house for nine years and I've never seen this before on any of the plants. We've had rain more often than in any summer I've lived here, so could it be related to that? The queen palm in my yard also sprouted some beige brush-like things alongside the palm fronds that I've never seen before either.

Do any of you Tucson gardeners have any info or advice for me? Thanks.

[Serenity1944]

I did a quick query on the net, assume you might have too but just in case -- I saw that it can be an insect that hides in a white growth that does look like a fungus…. it tells what to do to get rid of it.

[LordBalfor]

Originally Posted by Serenity1944

I did a quick query on the net, assume you might have too but just in case -- I saw that it can be an insect that hides in a white growth that does look like a fungus…. it tells what to do to get rid of it.

Yeah, it sure sounds like scale.

Cacti Care - Pests and Diseases On-line Guide to the positive identification of Members of the Cactus Family

https://www.google.com/search?q=cact...A&ved=0CB0QsAQ

Ken

[Jukesgrrl]

Thanks, but it doesn't look like the photos of scale that are online and it's on other plants in addition to cacti.

[seedy]

We're having an extended monsoon this year, some reports say it will continue until next spring with minibreaks. These happen every decade or so, this one is late/overdue and the frequency might go down as the area trends hotter/drier. Not my knowledge, but know some lifers who remember past floods and drenches.

So it's probably a fungus or something related to the extended humidity, and probably will go away when it stops, but might take some things with it when it does. If I wanted to fight it I'd be at a good nursery talking about fungicides.

[whitem3]

QUESTION:

Is there any kind of spray for our prickly pear that will help with the white fungus that has appeared on it?

ANSWER:

Most often when a white fungus-like substance appears on prickly pear it is an insect infestation not a fungus disease. It is easy to confirm this by seeing if you can scrape off the white fluff and if the white substance produces a bright red juice when it is squeezed between your fingers. If this is the case it is in fact the cochineal insect that is on your prickly pear.


Lady Bird Johnson Wildflower Center - The University of Texas at Austin

[jlawrence01]

I would call the Pima Co. Extension Office at the U of A as that would be their specialty. I do NOT have a number as the university website is less than easy to navigate.

[Serenity1944]

Another idea would be to take it to a nursery as someone there may know what it is.

[Prodigal Native]

Originally Posted by Serenity1944

Another idea would be to take it to a nursery as someone there may know what it is.

Although it is not exactly on Jukes' side of town, Mesquite Valley Growers would be my recommendation; great people and very knowledgeable. Civano would be my second choice, but they are even further away.

[Marcy1210]

Are there any landscapers in your area, or landscape contractors? They usually know what plant diseases or fungi are. Some of my neighbors have landscapers, and I'd ask them.