Know the difference between pest and beneficial mite species

As plants are being scouted for pests, it’s important to be able to distinguish pest mite species and beneficial mite species. Univ. of Conn. extension horticulture and greenhouse IPM specialist Leanne Pundt said beneficial predatory mites are generally very active, fast moving pear-shaped mites.
Phytoseiulus persimilis is one of the most commonly released predatory mites in greenhouse production. It has a bright orange-red, pear-shaped body and is very fast moving compared to the more sedentary, pest species, two-spotted spider mite.
To evaluate whether predatory mites are working, look for shriveled, dried up spider mites plus the presence of predatory mites and their oval-shaped eggs. P. persimilis eggs are oval and about twice the size of spider mite eggs. Eggs are laid close to a food source.
Spider mite eggs are round or barrel shaped and often found along the mid-vein on the underside of leaves. Spider mite adults are easily recognized by their two dark spots on either side of their body. Eggs, nymphs and adults can be found on the underside of the leaves.
To evaluate whether predatory mites are working, look for shriveled, dried up spider mites plus the presence of predatory mites and their eggs.