Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Chelicerata
Class	Arachnida
Subclass	Acari
Superorder	Acariformes
Order	Trombidiformes
Suborder	Prostigmata
Infraorder	Eleutherengona
Superfamily	Tetranychoidea
Family	Tetranychidae
Subfamily	Tetranychinae
Tribe	Tetranychini
Genus	Eotetranychus

Scientific Name

Eotetranychus hicoriae

Common Name

pecan leaf scorch mite

Author: H.C. Ellis, University of Georgia

Description

Numerous species of mites have been found on pecan leaves. Of these, seven species are common. All have eight legs but are tiny and difficult to see without magnification. The most common damaging species, the pecan leaf scorch mite, a spider mite, is greenish in color and may be found congregating near the mid-rib of leaflets.

Damage

Mites destroy leaflet tissue by their feeding, causing leaflets to have a scorched appearance. Fresh scorch injury appears as dark brown blotches. Severely injured leaflets turn entirely brown and drop. Damage most often begins along the mid-rib and spreads outward toward the leaf margins. Damage to a tree usually begins on the lowest branches in the interior of the tree and progresses upward through the tree. Damage is most severe in late summer and fall.

Seasonal History

Mites overwinter in crevices on the trees, particularly around leaf scars. They emerge in early spring and begin new populations. The life cycle (of E. hicoriae) involves an egg stage (2 - 4 days), a larval stage (2 - 4 days), three nymphal stages (7 - 13 days) and the adult. Adult mites live an average of about 16 days and females begin egg laying at 4 - 6 days of age. Each female lays an average of about 22 eggs. The average time from oviposition to adult is about 14 days under laboratory conditions but can be as little as 5 - 7 days under favorable field conditions. Populations usually increase gradually during the summer and the rapidly during late summer or early fall, reaching their peaks in September or early October.

When to Control

Materials used for aphid control sometimes keep mite populations suppressed. In late season, however, mite populations can become so heavy that these materials will not provide good control. Some insecticides, which kill beneficial organisms but not mites, can actually cause mite problems to increase. Specific controls should be applied when mites and mite damage appears frequently and generally on the foliage of low limbs (in 25% of leaves sampled). Spot treatments are often possible.

Originally compiled from

Archived article on pecan leaf scorch mites, Eotetranychus hicoriae.