Woody Ornamentals Insect and Mite Update – David J. Shetlar, Ph.D. The “BugDoc” The Ohio State University, OARDC & OSU Extension Columbus, OH © February, 2004, D.J. Shetlar, all rights reserved

Bulletin 504 – revised in February, 2003 ( next) Available at:

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Major Insect and Mite Groups Can kill plants – critical pests: borers!, some scales, some defoliators. Can disfigure plants – major pests: leafhoppers, defoliators, leafminers, some mites. Temporary damage – mainly nuisances: aphids, lace bugs, most soft scales, most caterpillars, mites, etc.

Borers Continue – Agrilis species Bronze birch borer

Borers Continued – Agrilis species Honeylocust borer Twolined chestnut borer

Bark Beetles (Scolytidae) (also called engraver or ambrosia beetles) Cedar bark beetle adult.Cedar bark beetle larvae. Pine Ips beetle and emergence hole. These beetles are sometimes called shothole beetles.

Borers Continue – White Pine Weevil – white pine & SPRUCE

Clearwing Borers (Sesiidae) This group is commonly listed as the Aegeriidae Lesser peachtree borer adult. Ash/lilac borer larva in lilac branch. Maple callus borer adult. Peachtree borer larva in sand plum.

Borer Insecticides Traditional Dursban Lindane DiSyston (disulfoton) Cygon (dimethoate) Bidrin injection Orthene injection (Professional only) Alternatives Tempo, Talstar (Onyx), Deltagard, Scimitar, Astro Merit injection (beetles only!) Flagship? (nursery) ??? X X ??

Borer Control Approaches Cultural – Use plants that are not prone to borer attack! Plant health care – plants in good growing conditions can usually repel borer attacks. Avoid Plant Damage – damaged plants are prone to attack. Biological – Usually not effective because they attack after infestation.

Oystershell scale attacks a variety of deciduous trees. The crawlers emerge about the time that black locust trees are in full bloom. This scale often kills smaller trees and branches if not controlled! Scales (armored) – Oystershell Scale

Pine needle scale females. Note pinkish eggs at end of scale test (shell) and a settled crawler at upper left. Group of pine needle scale settled crawlers (tan) and a couple of fresh crawlers (pinkish) in color.

Scale Control (crawlers) Traditional Diazinon Dursban Sevin Orthene (Professional only) Malathion Cygon DiSyston (disulfoton) Alternatives Tempo, Talstar, Deltagard, Scimitar, Astro Merit (soft scales) Flagship (nursery) Soaps & Oils X X ??

Caterpillars – The Gypsy Moth

Bagworms on spruce. Bagworm larva extending from bag. Male bagworm adult. Female bagworms remain in the bag as a pupa that contains the fertilized eggs.

Caterpillar Insecticides Traditional Dursban Sevin Orthene (Professional only) Malathion Alternatives Tempo, Talstar, Deltagard, Scimitar, Astro Conserve Merit (???) Flagship? (nursery) Bt Soaps or Oils X

Typical leaf speckling from rose leafhoppers. Rose leafhopper nymph. Rose leafhopper adult.

Elm cockscomb galls are a type of bladder or purse gall produced by an aphid. The Cooley spruce gall adelgid produces a pinecone shaped gall that is formed by swollen bases of needles. The young gall is on the left and the opened gall is on the right.

Galls – Bladder & spindle galls (eriophyid mites)

Oaks have over 300 different kinds of galls! This is a small sample – oak apple galls (upper left), oak bullet galls (above) and oak spangle galls (left). These are produced by gall wasps.

Calico scales, mature females. Scales – Lecanium (several) & Calico Soft scale nymphs usually settle on the undersurface of leaves for the first two instars. They can be controlled here!

Eastern tent caterpillar nest in roadside cherry tree. Tent caterpillars following web trail. Mature larva and cocoon. Egg mass.

Fall webworm adult male. Early fall webworm nest. Purpleleaf plum with dozens of fall webworm nests in September.

Honeylocust spider mites inhabit leaf undersurfaces. Oak mites inhabit the upper leaf surface. European red mite overwintering eggs European red mites clustering to balloon to new plants.

Cool-Season Pests – Spruce Spider Mite – inactive most of summer!

Hemlock rust mites are microscopic eriophyids that cause the foliage to appear yellowish or rust colored.

Miticides Traditional Kelthane Morestan Cygon Orthene ? (Professional only) Alternatives Avid Hexygon (eggs & larvae only, spider mites only) Floramite (spider mites only) Sanmite (spider mites only) Conserve Pyrethroids?? Soaps or Oils X X ??

Azalea lace bug damage. Note conspicuous leaf speckling. Typical lace bug adult. Note tar spots.

Lace Bug Control with imidacloprid (Merit): Some Issues Imidacloprid foliar sprays and soil drenches – work great, can provide season long lace bug control! Spider mites, especially twospotted, seem to flair up after imidacloprid applications. Appears that predators of spider mites also “sample” host plants and are killed by the imidacloprid!

Pine tortoise scale mature females on stem. Pine needle scale second instar nymphs and male “pupae” on needles.

Mimosa webworm nest in honeylocust. Mimosa webworm adult.

Black Vine Weevil Management What’s Lost? Ficam (Turcam) Orthene is professional only! What are the Alternatives? Merit! (home owner product available, apply to soil, NOT mulch, not for adults!) Pyrethroids for Adults DiSyston (disulfoton) (home owner products available, BVW not named on label, apply to soil!)

Emerald Ash Borer Discovered in Detroit area, now in over 1000 square miles in southeastern Michigan. Infestations found in Toledo area, far northwestern Ohio, and in Columbus area in November! Watch for declining ash trees – tops dying out downward. If D-shaped holes are present, then emerald ash borer is likely the only cause! Larger, round or oval holes are from other native borers.

Periodical Cicada – Brood X This large brood will emerge in May and adults will persist through June.