Pine Tortoise Scale
Louis F. Wilson 1
1 Principal insect ecologist, North Central Forest Experiment Station, maintained by the Forest Service, U.S. Department of Agriculture, in cooperation with the University of Minnesota.
The pine tortoise scale (Toumeyella numismaticum (Pettit & McDaniel)) is a soft scale insect that periodically kills hard pines. It is a native insect and was first reported in eastern Nebraska in 1911 and later officially described in 1920 from specimens obtained in northern Wisconsin . It was probably carried into Nebraska from Wisconsin on infested, wild jack pine seedlings used to establish an experimental planting in 1891.
The currently known range is from eastern New York south to Maryland and west through the North Central States to the Great Plains wherever its hosts are found. It is also known to occur in Manitoba and Ontario, Canada.
The taxonomy of the genus Numismaticum is still undecided, and it is possible that some reports of T. pini King actually refer to the pine tortoise scale.
Some collections of T. pini from Pennsylvania, Maryland, and West Virginia are now considered to be at least a form near T. numismaticum.
Damage and Evidence of Attack
Associated with this scale is a sooty mold that grows on honeydew—a secretion given off by the immature female scales. Together, the honeydew and the black mold (fig. 1) on the needles give the tree a shiny dark appearance. Ants often feed on the honeydew.
The first-instar nymphs—called crawlers—are nearly as large as the eggs and oval and have six short legs. They are reddish, and to the naked eye they appear as"fine red pepper" sprinkled on the twigs.
The older nymphs are legless, helmet-shaped insects. The female nymphs are larger than the males and often wrinkled and dark brown to black. When mature, the females (fig. 2) are 3/16 to 1/4 inch long and reddish brown. The most obvious evidence of the presence of male scales is the puparia. These are oval, white, and trans-lucent and about 1/8 inch long (fig. 2). The adult males, which are seldom seen, are winged and barely 1/6 inch long.
Life History and Habits
The crawlers settle down and suck the sap of the host and shortly afterward become sedentary, legless nymphs. A white, powdery substance develops on the margins of the young nymphs, and in about 2 weeks sexual differentiation becomes apparent. About 1 week later the smaller, male nymphs are fully developed. They pupate and emerge as small, flylike adults. They immediately search out and fertilize the still immature, immobile, female nymphs and then soon die.
The fertilized females continue to develop until late fall, when they hibernate (fig. 3). They resume activity in the spring about the time the buds begin to swell. Honeydew is secreted copiously during this time and is accompanied by the sooty mold and ants. The females mature in early June.
Because malathion has a short period of effectiveness, crawlers that have become sedentary—about 1 week after hatching—will not be affected by the chemical. Consequently, spraying should be done twice—first within 4 to 5 days after the first hatching and again 5 or 6 days later.
Store pesticides in original containers under lock and key—out of the reach of children and animals—and away from food and feed.
Apply pesticides so that they do not endanger humans, livestock, crops, beneficial insects, fish, and wildlife. Do not apply pesticides when there is danger of drift, when honey bees or other pollinating insects are visiting plants, or when they may contaminate water or leave illegal residues.
Avoid prolonged inhalation of pesticide sprays or dusts; wear protective clothing and equipment if specified on the container.
If your hands become contaminated with a pesticide, do not eat or drink until you have washed.
In case a pesticide is swallowed or gets in the eyes, follow the first aid treatment given on the label and get prompt medical attention. If a pesticide is spilled on your skin or clothing, remove clothing immediately and wash skin thoroughly.
Do not clean spray equipment or dump excess spray material near ponds, streams, or wells. Because it is difficult to remove all traces of herbicidesfrom equipment, do not use the same equipment for insecticides or fungicides that you use for herbicides.
Dispose of empty pesticide containers promptly. Have them buried at a sanitary land-fill dump, or crush and bury them in a level, isolated place.
WARNING: Recommendations for use of pesticides are reviewed regularly. The registrations on all suggested uses of pesticides in this publication were in effect at press time. Check with your county agricultural agent, State agricultural experiment station, or local forester to determine if these recommendations are still current.
A NEW MENACE TO SCOTCH AND JACK PINE. J. H. ALLISON and L. W. ORR. Jour. Forest . 27:821-824. 1929.
CONTROL OF TOUMEYELLA SCALE ON VIRGINIA PINE. A. T. Drooz. Jour. Econ. Entomol. 50:835. 1957.
THE PINE TORTOISE SCALE (lecanium numismaticum PETTIT AND MCD.) IN NEBRASKA. L. M. GATES. Jour. Econ. Entomol. 23:544-547. 1930.
THE PINE TORTOISE SCALE IN WISCONSIN. P. A. JONES and R. D. SHENEFELT. Univ. Wis. Res. Note 30, 3 p. 1956.
NATURAL FACTORS CONTROL THE PINE TORTOISE SCALE IN THE NORTHEAST. THOMAS MCINTYRE. Jour. Econ. Entomol. 53 :325. 1960.
SOME ASPECTS OF THE BIOLOGY AND DISPERSAL OF THE PINE TORTOISE SCALE (toumeyella numismaticum PETTIT AND MCDANIEL) (HOMOPTERA: COCCIDAE). F. B. RABIIN and R. R. LE‑ JEUNE. Canad. Entomol. 86:570-575, illus. 1954.
TWO NEW SPECIES OF THE GENUS HYPERASPIS (COLEOPTERA: COCCINELLIDAE). W. Y. WATSON. Canad. Entomol. 92:230-234, illus. 1960.
U.S. Government Printing Office: 1971 O---409--975
|Pesticide recommendations in publications from 1975 or earlier may no longer be be valid. Some pesticide products may not be registered anymore or may not be available to the public for use. For current recommendations, consult your local forest pathologist, county agricultural agent, or state extension agent about restrictions and registered uses of particular pesticides.|