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News Release 8-22-2002 |
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INSECTS ATTACKING TULIP POPLARS IN CENTRAL WEST VIRGINIA West Virginia Commissioner of Agriculture Gus R. Douglass announced
that there have been reports of heavy scale infestations on tulip
poplar, also known as tuliptree, in central West Virginia this summer.“These
tulip poplars are infested with tuliptree scale, said Commissioner
Douglass. “Characteristics of heavily infested trees include
sap dripping onto anything beneath the trees and a black, coal dust-like
substance on foliage and branches.” Tuliptree scale, Toumeyella Iiriodendri, is a sap-sucking insect
that feeds on the sap from the host tree. It is one of the largest
of the scale insects and resembles small, “turtle-shell”
looking lumps on the twigs (see photograph). Each lump is one scale
insect. When they occur in large numbers, and populations tend to
build up rapidly, they encrust twigs to a point where the woody
tissue is no longer visible. Adult females may produce as many as
3,000 or more crawlers (young scales) in late August and September.
The crawlers are the only mobile stage of the insect. Once they
settle down, start feeding, and molt for the first time, they never
move again because they lose their legs. As the scale matures the
following growing season, it develops the shell-like covering over
itself. This particular scale is associated with a lot of honeydew, which
is the excreta of sap sucking insects. This is the sticky, sugary
“sap” that drips down on anything beneath where the scales
are feeding. Sometimes you might notice an increase in bee, wasp
or ant activity on a tree that is infested with scales. They are
after the honeydew. Additionally, the honeydew is often colonized
by a black sooty mold. This gives the tree the appearance that it
has been coated with coal dust. So, now you not only have the scale
taking nutrition away from the tree, but you also have the sooty
mold building up to levels where photosynthesis is inhibited because
sunlight can’t penetrate to the foliage. Damage to the host
tree consists of discolored foliage and death of infested twigs.
Commissioner Douglass added, “While there are several predators
and parasites that are common enemies of this scale, they rarely
are able to control the tuliptree scale in outbreak years. Therefore,
chemical control measures are recommended for heavily infested yard
trees. Control is not practical for large trees or trees in a forested
setting. Control measures are targeted at the crawlers and should
be applied during September. Recommended chemicals include malathion,
diazinon, Orthene, Cygon and Sevin.” For information on other forest or urban tree pest problems contact
the West Virginia Department of Agriculture’s (WVDA) Plant
Industries Division’s Pest Identification Laboratory at (304)
558-2212. For more information on the WVDA, contact Buddy Davidson, Communications Officer, 304/558-3708 or bdavidson@ag.state.wv.us. |
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©2001, 2002 West Virginia Department of Agriculture, All Rights Reserved |
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