I've had to throw out a bunch of plants or chop off
large diseased portions. But because the problem just
keeps popping up, I'm beginning to worry that I will
soon need to replace dozens of plants.

What is this??? Is it treatable?

I can't say for sure that your problem is mites, but they can do the type of damage that you describe. Mites are very tiny, almost invisible to the naked eye, and some are not visible. Sometimes, on the undersides of leaves, they can leave a bit of a web, but not all mites leave a web.

Mites can cause scabby growth on aloes (and cacti), and they can cause deformities such as twisted, or stunted, or bizarre flower stalks and flowers. They can cause scabby growth on leaves and stems and can seriously deform a plant with twisted growth combined with scabby surfaces. The stem and leaves can look corky, or bumpy or like acne, or worse, even like dried fish scales.

Mites are tiny and flourish in dry weather and or humid hot weather (but not rainy). Some aloes are more susceptible than others. Control is not straightforward because many miticides have been taken off the market (EPA rulings that they are a problem). Sometimes, pryrethrum or synthetic phyrethum (pyrethroids) are useful, sometimes insecticidal soap can work. You have to spray on the plants and perhaps even cut the damage and gross areas off. You may have to reapply several times, and then once or twice per season. The thing is that many insecticides don’t work so well on mites; having 8 legs mites are more closely related to spiders than insects—so be persistent. You won’t know if you’ve succeeded until new growth comes out healthy.

I can't find photos of aloe mite damage. But the link takes you to a page where there are photos of cactus mite damage. The main thing is that the little guys (tiny) bite the stem a billion times while they are sucking juice out of the stem. So, the stem forms a wound or scab, and the scab provides more places for the mites to hide and have babies. And then they bit the stem a billion times a billion times, and the damage adds up.

The result is that large areas of the leaves and stem are brown, and so they cannot do photosynthesis (this requires green). So, the plant grows slower. Also, the damaged areas are deformed or ugly or cause other diseases to come into the aloe. Think of a bad case of mange or ringworm or permanent poison oak.

By the way, there are two pages of photos at the cactus mite place (link below). They are gross and ugly, but may help you understand how a billion little mites can damage a plant. So, be sure to go the home page and check out other pages.

Cordially,

Conroe Joe

If this is what you have, you might wish to be rid of the plant.

I'm afraid your picture might as well have been taken in my back yard.

I guess that means a large part of my garden is going to be hitting the green bin.

Thanks for the information. You were on the money.

Biz