Identifying Persea Mites

There are three types of mites that feed on California avocado trees. All three of these mites damage avocado leaves by removing chlorophyll during feeding. Excessive feeding can lead to rapid loss of avocado leaves, effecting the number of avocado fruit on the tree.

• One of the best ways to identify which type of mites are on the avocado trees is to look at the leaf damage caused by the mite.
• Persea mites feed in colonies beneath protective webbing in nests that are formed along midribs and veins on the undersides of avocado leaves. The webbing is a good way to identify the mites as persea mites. Feeding damage produces circular yellow to dark brown necrotic spots.
• The avocado brown mite, feeds on upper leaf surfaces that look “bronzed” by feeding damage.
• The six-spotted mite is very similar in appearance to persea mite and it also feeds on undersides of leaves. Six-spotted mites prefer to feed adjacent to the midrib and large lateral veins and leave behind purplish irregular necrotic spotting.
• Persea mite populations typically begin building in mid-summer and cause most damage to leaves by late summer.  Once defoliation occurs, persea mite populations typically decrease due to lack of food.