I have been doing a bit of research on the use of DMSO as a surfactant and found some interesting stuff.... My thought process with Aloe mite and Agave mite is that because this bug can live inside the gall, it takes penetration of the miticide into the tissue to have any effect. As mentioned already, Forbid is advertised to have this translaminar effect.. DMSO is a solvent that can increase penetration of it's solution into both plant and animal tissue. I found reference to it being used to that effect invitro and with herbicides... Might be worth playing around with to get at these buggers...
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Herbicidal compositions containing DMSO - US Patent 6133200 Description