Pear thrips on forest trees

Historic, Archive Document

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Glert

Pear Thrips on Forest Trees

Reserve

aQL598

.3

.T4027

1989

The pear thrips, Taeniothrips inconsequens
(Uzel), an imported species first noted in Cali¬
fornia in 1904 and now throughout the United
States, is a common thrips found on many plants,
but particularly fruit trees. Pear thrips have been
considered a serious forest pest only recently
(1979, when they, along with Thrips calcaratus
Uzel, caused widespread defoliation in Pennsyl¬
vania). Infestations of forest trees have been
reported from New York, Pennsylvania, and all of
the New England states.

The adult pear thrips are tiny (less than 2 mm
long), slender, dark brown, and have long, nar¬
row wings covered with a hairy fringe. Immature
stages are white with red eyes and wingless.
Around mid-June, the thrips enter the soil as lar¬
vae where they mature and overwinter in the soil.
They emerge in early spring to feed on swollen
buds and expanding leaves and to reproduce.
Eggs are laid in the leaf epidermis, mainly of
veins and petiole, leaving brown scars.

In forest stands, maples (especially sugar maple),
birches, ash, black cherry, and beech are all af¬
fected. Other forest trees may be affected as well
Symptoms include fallen green leaves, leaves
smaller than normal, cholorotic and tattered
leaves, leaf margins frequently browned or wilted,
and leaves puckered or wrinkled. Where the out¬
break has persisted longest, growth decline and
crown dieback have occured.

Photo credits:

1. M. Miller-Weeks, F.S.

2. Pennsylvania Bureau of Forestry

3. Ron Kelley, Vermont Department of Forests,
Parks, and Recreation.

United States
Department of
Agriculture

FnrpQt ^pr\/irp

Northeastern Area L OATALOGING PREP [

in cooperation with

your State agency NA-FB/P-34 Revised 5/89

Photo 1: Maple leaves injured by pear thrips.

Photo 2: Adult pear thrips on sugar maple bud.

Photo 3: Maple leaves injured by pear thrips.
Note oviposition scars on veins
and petiole.

Send reports of damage to:

James O'Brien and
Parker Snowden
Forest Pest Management
NA-S&PF

NATIONAL AGRICULTURAL LIBRARY

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