Etiolation – abnormal growth caused by lack of adequate sunlight. New growth comes from the center of the plant, if your plant starts to look stretched, lighter in color, the features of the leaves start changing (teeth, texture, pattern/spots, length/thickness of leaf), it is likely your plant is not getting enough sun. Very carefully and very slowly introduce it to stronger light.
Sunburn – Aloes can take a lot of sun, but if they aren’t used to it they WILL burn. Some species in some places can take full sun, I grew my Aloe vera in full sun for a couple years here in Texas with no issues. Most people mistake the protective color changes (brown for vera), or stress colors, for sunburn, but really it will look like the color is being bleached, and that bleached spot will usually cause a permanent scar as it dries. Slowly introduce your plant to more sun than it is used to if you are moving it.
Aloe mites – Causes deformed growths on the plant. Pretty much unavoidable if you collect Aloes. Can be treated/prevented with Sevin with Carboryl, Orthene (acephate) and/or Avid, along with removing any growths. Make sure to completely destroy any plant material that you remove, it spreads very easily. If it’s not a plant you particularly care about and have a large collection, you might just toss the whole plant instead of trying to treat it, and also start preventative treatment of your other plants. It’s best to treat every new plant you receive as a “just in case” measure since the mites are undetectable until the galls start showing up. It is unfortunately not possible to tell if a plant has mites (because the mites are not visible) until the galls they cause start showing up. Early signs are raised brown or yellow rough lines on the pattern or edges of the leaves of the plant. It can also cause deformed bloomstalk growth, some of the “Fantasy Hybrids” seem especially susceptible to it.
Edema – caused by excessive water, poor drainage, hot roots, and/or humidity fluctuations. Can look similar to sunburn damage, leaks when fresh and dries up as a scar in the same way.
Fungus – Usually circular brown spots that cause permanent damage, on lower leaves especially. Can also just be small brown or black spots that slowly cover an entire leaf. Caused by poor drainage and/or too much water. Even with a well draining soil mix, here in humid AF Texas some Aloes end up with these brown spots..the maculate/spotted group of plants seem especially affected. Aloe Rust is another type, I haven’t had any of mine get it yet, but it’d be a good thing to google to familiarize yourself with.
These are not all the diseases or examples of damages you might experience growing Aloe, but they are some of the more common ones.
AloeHoarder 