I have come to understand that when a product controls for other sucking insects the mites in question are usually spider mites. Any non systemic is going to have a hard time dealing with eriophid (spelling?) mites, which Aloe and Agave mites both fall under. They generally live inside the plant causing deformities in with different outward appearances. On top of that these mites are also microscopic whereas spidermites are small but to some extent and to people with good eye sight just visible with the naked eye. When you see a plant that has obviously been affected by Aloe or Agave mite you are not actually seeing any of the mites, just the damage they cause.
In Aloes you get the crazy looking gall like growth on leaves or inflorescences, while in Agaves the damage is less extreme looking, but still very disfiguring in bad cases, it occurs in the form of greasy looking spots over centered around dried out brown lesions.
