ornamentals pests: mites - their groups, diagnosis, and control david j. shetlar, ph.d. the bugdoc...

Ornamentals Pests:Mites - Their Groups,

Diagnosis, and Control

David J. Shetlar, Ph.D.The “BugDoc”

The Ohio State University, OARDC & OSU Extension

Columbus, OH

© July, 2007, D.J. Shetlar, all rights reserved

Main Mite Groups

• Spider Mites (Tetranychidae) – Oligonychus, Tetranychus, Panonychus, Eurytetranychus, Eotetranychus, Bryobia.

• False Spider Mites (Tenuipalpidae) – Brevipalpus

• Eriophyid Mites (Eriophyidae) – bud, gall, rust mites.

Other Mite Terms

• Cool-season Mites – most active in spring and fall seasons, when temperatures are above freezing but blow 80F during the day.

• Warm-season Mites – Seem to do best during summer warm periods, also do well in drought.

• Gall Mites – cause plant distortions or abnormal growths.

• Rust Mites – cause general yellowing or bronzing of the foliage, but mites are almost too small to see.

Bryobia spp.

• Clover mite (B. praetiosa) – cool-season grass and weed feeder.

• Honeysuckle bryobia (B. lonicerae) – common on shrub honeysuckle

Panonychus spp.

• European red mite (P. ulmi) – warm-season mite on fruit trees and Crataegus.

Stippling of apple leaf.

Adult female

• European red mite (P. ulmi) – warm-season mite on fruit trees and Crataegus.

Adults ballooningOverwintering egg clusters

(dormant oils?)

Eotetranychus spp.(dozen species, yellow to green)

• Honeylocust mite (E. multidigituli) – warm-season on leaf undersurfaces.

• Linden mite (E. tiliarium) – warm-season on leaf undersurfaces.

Eotetranychus spp.(dozen species, yellow to green)

Tetranychus spp.

• Twospotted spider mite (T. urticae) – warm-season mite of greenhouses, annuals and perennials, winged euonymus and some Viburnum.

Twospotted spider mite (T. urticae) –

Oligonychus spp.(many species, dark red, brown or green)

• Spruce spider mite (O. ununguis) – cool-season conifer feeder.

• Southern red mite (O. ilicus) – cool-season, attacks broadleaf evergreens.

• Oak spider mite (O. bicolor) – warm-season, upper leaf surface.

• Maple spider mite (O. aceris) – warm-season, lower leaf surface.

• O. newcomeri – warm-season, Amelanchier leaves.

• Spruce spider mite (O. ununguis) – cool-season conifer feeder.

Bronzing of spruce

Mites & webbing on fir

• Spruce spider mite (O. ununguis) – cool-season conifer feeder.

Spruce spider mite populations (thick line) over the 1993 season in Columbus, OH. Note that the population of active mites disappears in early July due to several days with temperatures above 29°C (=86°F), a characteristic of a cool-season mite.

• Southern red mite (O. ilicus) – cool-season, attacks broadleaf evergreens.

• Oak spider mite (O. bicolor) – warm-season, upper leaf surface.

• Oak spider mite (O. bicolor) – warm-season, upper leaf surface.

• Maple spider mite (O. aceris) – warm-season, lower leaf surface.

False Spider Mites – Tenuipalpidae

• Privet mite (Brevipalpus obovatus) – warm-season, flat mite numerous hosts.

Phaelenopsis mite, another false spider mite.

Eriophyid Mites

• Rust Mites – free-living “vagrants” on foliage surface, causing yellowing and russeting of foliage.

• Gall Mites – Cause abnormal plant growths, bladder and spindle galls, and erineum.

• Bud Mites – bud rosettes, new growth distortion, “blasted” buds.

Eriophyid Mite Characteristics

Two pairs of legs Small!

Able to flip into air to balloon!

Hemlock rust mites.

Privet rust mites.

White pine rust mites.

Spruce rust mites.

Baldcypress rust mites.

Maple bladdergall and spindlegall mite damage.

Maple erineum galls.

Pear leafblister mite damage.

Pear leafcurl mite damage – a different species!

Ash flowergall mite damage to flower buds

Ash flowergall mites “questing” for air currents to balloon!

Coneflower Rosette Mite

Pine Rosette Mite

Juniper tip-dwarf mites.

MiticidesTraditional

• Kelthane

• Morestan

• Cygon

• Orthene ? (Professional only)

• Sevin (eriophyids only)

Alternatives

• Avid (all mites!)

• Hexygon (eggs & larvae only, spider mites only)

• Floramite (spider mites only)

• Sanmite (spider mites only)

• Forbid (all mites!)

• Conserve

• Pyrethroids – NO!??

• Soaps or Oils

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