European red mite, Panonychus ulmi (Left), and twospotted spider mite, Tetranychus urticae (Right). Note that the ERM is orange with white spots while the TSSM is greenish with two black spots.
The McDaniel mite, Tetranychus mcdanieli, is about the same size and color of the twospotted spider mite but lacks the distinct spots. Individual mites can look quite similar between the two species so correct identification generally requires that you have numerous specimens (say 25 adults).
Numerous predaceous mites species keep spider mites in check. They are about the same size as spider mites but the females are much more oval and are buff-colored. The eggs are very oval as well and the immatures are clear. Some, such as Neoseiulus fallacis, shown above, has resistance to organophosphate insecticides.
Gall and Rust Mites
Apple rust mites on apple leaves.