The Gall mite that causes the abnormal growths on aloes cannot be seen with the naked eye, which makes it difficult to control before it has infiltrated your plant(s).

Very often the first sign of gall mite is a new inflorescence that emerges from the plants all crooked and bent, or even just a frilly growth on the side of a leaf or inflorescence. This will soon develop into unsightly galls on the inflorescence or plant as it matures. The same galls may also start as an irregular growth on the base of some of the older leaves, often where an earlier inflorescence has dried.

The old flowers of the very popular tree aloe, Aloe Barberae (previously Bainesii) are often the source of infestation. Huge galls form on old inflorescences and, if left untreated, spread their unwelcome inhabitants far and wide for many years, because the galls prevent the flowers from drying out by demanding to be fed by the plant. The gall mites spread through the air and to other aloes in contact with the first patient, so keep an eye open for signs of infestation on nearby aloes.

Note that the growth is the aloe’s reaction to the chemical secreted by the mites. The galls may keep on growing even after the mites are killed, but it is better to maintain the treatment until the galls no longer appear or enlarge.

1. Some growers have rid their gardens of this pest by just cutting away the affected tissue with a sharp blade (e.g. carpet knife). This will have to be followed up by subsequent cutting as soon as the cancer-like growths re-appear. It will increase the effectiveness of this treatment if the open cut(s) can be treated with Blue Death powder or a strong solution of a systemic insecticide. The whole plant can be sprayed with the manufacturer’s recommended solution of the same insecticide a day or so later.

Insecticides/miticides that can be used in an alternating spray programme: Aphicide, Parsec, Pride, Milbeknock, Blue Death (powder). Be careful not to cut or spray during wet weather, and preferably not while birds and bees are actively feeding on the flower. Some mite populations show resistance to systemic insecticides, or develop resistance, so alternating treatment is important.

2. We previously suggested that Formaldehyde or formalin (40% solution) can be painted directly onto the gall/growth (no cutting). However, the International Agency for Research on Cancer (IARC) classifies formaldehyde as a known carcinogen. We therefore suggest that you do NOT use this method to get rid of the gall mites.

3. Jeyes Fluid is a safer alternative to formaldehyde. It is not as dangerous to the plant and, if painted onto the gall/growth, is easier to control run-off because it has a thicker consistency. Jeyes Fluid should be painted directly onto the gall/growth. It will kill the growth, so cutting is not necessary, in fact we recommend that no cutting takes place so that the chemical is prevented from entering healthy plant tissue. It may be necessary to repeat this treatment if signs of fresh growth is visible after a week or 10 days.

Updated 25 January 2024