U.S. Department of Agriculture

Forest Seruice Research Note S E- 273 February 1979

THE INTRODUCED PINE SAWFLY,l A DEFOLIATOR OF

WHITE PINE NEW TO NORTH CAROLINA

by A. T. Drooz, C. A. Doggett, and H. C. Coppel’

Abstract. -The introduced pine sawfly, Diprion similis (Hartig), was reported in North Carolina for

the first time in 1978. The initial finding was of the cocoon stage in the autumn of 1977 at Linville

Falls. It is a European species that defoliates eastern white pine in this country and is capable of

damaging hard pines. A brief account of its description, hosts, life history, survey, and control is

included.

KEYWORDS: Diprion sin&s, introduced pine sawfly, defoliator of eastern white pine.

The introduced pine sawfly, Diprion sirnilis

(Hartig), was found in North Carolina for the first

time in the Linville Falls area of Avery County by

Coleman Doggett in September 1977 (Doggett 1978).

At that time cocoons occurred on Fraser fir, Abies

fraseri (Pursh) Poir., which is not a host. The preferred host, eastern white pine, pinus strobus L., was

nearby. In October 1978, sawflies were reported also

in Caldwell, Burke, and Jackson Counties.

The first adult sawflies emerged from cocoons in

the spring of 1978 and were identified tentatively by

A. T. Drooz as D. similis. Sawfly specialist D. R.

Smith, USDA Systematic Entomology Laboratory,

confirmed the identification.

Although new to North Carolina, this pine sawfly from Europe and Siberia has been known in the

United States since its discovery in Connecticut in

1914 (Britton 1915). Wilson (1966) reported the U.S.

distribution to be from the New England States to

Minnesota and south to Virginia. The report of its

presence in Virginia is incorrect. Cocoons sent from

New Haven, Connecticut, to a laboratory in Falls

’ Diprion similis (Hartig) (Hymenoptera: Diprionidae).

2Drooz is Principal Entomologist, Forestry Sciences

Laboratory, Research Triangle Park, N. C.; Doggett is Staff

Forester, Pest Control, N. C. Division of Forest Resources,

Raleigh, N. C.; and Coppel is Professor, Department of

Entomology, University of Wisconsin, Madison, Wis.

Church, Virginia, were erroneously labeled with that

location.3 Southern Pennsylvania was the previous

nearest known locality to North Carolina (Coppel and

others 1974).

The introduced pine sawfly has been reported to

attack and develop upon a number of species of

pinus, especially eastern white pine, I! strobus, but

also with decreasing frequency, Scotch pine, I!

sylvestris L., jack pine, P. banksiana Lamb., and red

pine, P. resinosu Ait., among others (Coppel and

others 1974). Its success on the various species of

southern pines remains to be learned.

. . .c

In the North, this sawfly has two generations per

year. When weather is favorable, a partial third generation may be produced. In the mountains of

western North Carolina, conditions are favorable for

three complete generations.

Defoliation by the introduced pine sawfly can

result in the death of white pine, but extensive

mortality has not resulted from defoliation in the

North (fig. 1). However, the value of Christmas tree

plantings is reduced even by light defoliation.

Eggs are laid in pine needles and covered with a

frothy green material (fig. 2). Cuts made by the ovipositor cause needles to curve and possibly die. Mature

3Smith, D. R. October 26, 1978. Personal communication.

Southeastern Forest Experiment Station - Asheuille -North Carolina
Figure l.-Eastern white pine heavily defoliated by the introducedpinesawfly. (Photo courtesy of H. C. Coppel.)

feeding larvae are about 25 mm (1 in.) long and appear

marbled white, yellow, and black with a jet-black head

(fig. 3). Ultimate-stage larvae which do not feed are

lighter in color, shorter, and have gray head capsules

(fig. 4). This is the stage of the sawfly that constructs

cocoons. The leathery-brown cocoons are fastened to

twigs, needles, and bark of host and nonhost trees

(fig. 5a). They may even be found on grass, weeds,

and shrubs (fig. 5b). Because it forms its cocoons on a

variety of substrates, the introduced pine sawfly is a

potentially destructive “hitchhiker” into new areas.

The adult female is a stout yellow and black sawfly

with serrate antennae (fig. 6). Males are smaller,

mostly black, and have feathery antennae (fig. 6).

Virgin females produce a powerful chemical

(pheromone) which attracts the males (fig. 7). These

females can be caged to attract males, or pheromone

can be extracted from the females and used in traps

Figure 2.-Eggs of the introduced pine sawfly are cut into the

needle in rows and covered with a frothy green material.

to determine presence of adult males. Pheromonetrap surveys can delimit the distribution of the sawfly

accurately even where populations are low (Coppel

and others 1974).

Twenty-five to 40 years ago Canadian entomologists liberated a number of species of parasitic insects

which attacked the introduced pine sawfly with beneficial results (Munroe 1971). These insect parasites

have since migrated to northern states where they

play a role in the biological control of the sawfly.

TWO notable hymenopterous parasites originating

from Europe are the solitary ichneumon-wasp,

Exenterus amictorius (Panzer), which attacks prespinning larvae and the gregarious torymid, Monodontomerus dentipes (Dalman), which attacks

cocoons and destroys their contents. If not already

present, attempts to introduce these parasites in

North Carolina should be made. Numerous other

Figure 3.-Final feeding-stage larva of the introduced pine

sawfly has a black head and a darker body than the next

stage, which spins the cocoon.

Figure 4.-The ultimate-stage larva has a gray head and lighter

colored body than the final feeding-stage larva. The

insect spins its cocoon in this stage.
Figure S.-Cocoons of the introduced pine sawfly are tough

and brown. They are spun on (A) host pines or (B) nonhost species such as grasses. (Photos courtesy of H. C.

Coppel.)

Figure 6.-A mating pair of introduced pine sawflies. The

female is stout and has serrate antennae. The male is

smaller and has feathery antennae.

Figure 7.-Males attracted to a sticky trap baited with a virgin

female introduced pine sawfly. This simple device is a

good survey tool.

insects prey on or parasitize the introduced pine sawfly to some extent (Coppel and others 1974). Liberation of these parasites in North Carolina might reduce

damage by the sawfly.

Chemical insecticides can be effective on individual trees and small plantings. State or federal

entomologists, district foresters, or county agents

should be consulted for the currently recommended

insecticides.

LITERATURE CITED

Brltton, W. E.

1915. A destructive pine sawfly introduced from

Europe. J. Econ. Entomol. 57:829-830.

Coppel, H. C., J. W. Mertins, and J. W. E. Harris

1974. The introduced pine sawfly, Diprion similis

(Hart@ (Hymenoptera: Diprionidae): a review

with emphasis on studies in Wisconsin. Univ.

Wis. Res. Bull. R2393,74 p.

Doggett, C. A.

1978. N. C. Div. For. Resour., For. Pest Newsl.

20(6): 2.

Munroe, E. G.

1971.

Wilson, L. F.

1966.

Part IV Biological control in Canada, 1959-

1968: Synopsis. 48. Status and potential of

biological control in Canada. In Biological

control programmes against insects and weeds

in Canada. Commonw. Inst. Biol. Control,

Agric. Bur. Tech. Commun. 4, p. 213-255.

Introduced pine sawfly. U.S. Dep. Agric. For.

Serv., For. Pest Leafl. 99,4 p.
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