Interesting information. But instead of using isopropyl alcohol, try purchasing ethanol alcohol. But make sure it is not denatured ethanol. The reason why is because ethanol is safe to consume, and evaporates quickly. You can use a 1:10 ethanol:water ratio, and spray it every other day until the spider mites are gone, however this is just a suggestion and is completely hypothetical.

Article from erowid on denatured alcohol:

"Denatured ethanol, which is ethanol which has been intentionally poisoned so that it is undrinkable. The reason for doing this is that drinkable ethanol is taxable under the Tobacco Alcohol and Firearms people, and denatured ethanol has uses in chemistry and cleaning. The point is that you should under no circumstances use denatured ethanol because it will make you sick or kill you or cause cancer or all three."