Photos from the WFIWC Archives:
Insects and Damage

Pine Butterfly, Neophasia menapia (Felder & Felder). This pierid is similar in appearance to the common cabbage butterfly but differs in having black borders on the wings instead of spots and its primary host is ponderosa pine instead of your cabbage and broccoli. Its population mounts to impressive levels after long intervals of time and generally not in the same area. Outbreaks are short lived (2-3 years). Population collapse seems due to effects of starvation although an ichneumon was credited in some accounts.

I began employment in California in 1950 and often saw this white butterfly flitting about the tops of old growth pine in Lassen Co. during late summer. However, I never saw any sign of defoliation or any of its immature stages. Throughout my subsequent work in Idaho, I have rarely seen this butterfly. The only time that I have actually seen an out break was in 1973 on the Bitterroot N.F., Montana. That outbreak was treated experimentally with Mexacarbate and Bacillus thuringiensis (Dewey et al. 1974) and I took the accompanying photo there.

I am intrigued by several aspects of this native forest insect and have decided to compile information here about three historical outbreaks in Idaho for which I have information at hand. But, first, a story to reinforce that this insect is rarely seen in its immature (damaging) stages. In 1958, I visited Noel Wygant and Bill Wilford at the Fort Collins, CO, forest insect lab. They took me in an open WW II surplus military jeep into the surrounding mountains. I think that they were testing my mettle by driving off-road and up-and-down some breathtaking slopes. At one point, they stopped to examine a partially defoliated young pine but did not recognize that the larvae were the pine butterfly. I was impressed by that because both men were older than I and they had worked extensively in the west, yet they had no familiarity with it. I speculate that probably few forest entomologists have ever seen an infestation of the pine butterfly. I wonder ... how many have you seen?

Moscow Mountain, Latah Co., Idaho, 1896 - 1898. Some observations of this outbreak were recorded by the prominent Dipterist, J.M. Aldrich, who was a professor at the University of Idaho from 1893 - 1913 (Aldrich 1912; letter to R.C. Barker 1922). He pointed out that up to 1890, this insect was extremely rare in collections. During 1896-1898, however, an outbreak occurred on Moscow Mountain, seven miles distant. He noted that "the woods was full of butterflies. On one occasion a strong breeze came up from the Northeast at Moscow and in a few minutes the town was simply alive with the white butterflies, which had been blown from the neighboring mountains." Aldrich reared an icheumon, Theronia fulvescens, from pupae of the butterfly. "The parasite reached its maximum abundance in 1898, at which time it swarmed in the woods in late summer in incredible numbers. In places, the air was full of them and they made a very perceptible humming sound like a swarm of bees. At the University of Idaho, about seven miles from the forest, it was abundant and on one occasion I collected 40 specimens by picking them off the walls of the administration building while going once around it - and this seven miles from where any of them matured. ... In ten years afterwards I think I saw only one specimen (of pine butterfly) alive."

Payette National Forest (New Meadows - McCall area), Idaho, 1921-23. The next outbreak occurred during 1921-1923 on somewhat scattered areas totaling 27,000 acres in the upper Little Salmon and Payette River drainages (Evenden 1926, 1940). About 25% of the mature pine died. The course of infestation, including parasitism by Theronia fulvescens conformed to the 1896-1898 infestation near Moscow, Idaho. Tall, mature, trees were severely defoliated in 1922, the peak year. In 1923, the infestation was confined largely to small trees. He attributed this to there being no needles on the tall trees on which to lay eggs.

Up to this time there was some confusion concerning the seasonal history of the butterfly. Aldrich, for example, had thought that it was "... much like its near relative the cabbage butterfly in having continuous series of broods during summer, probably three or four." Others thought that it overwintered as pupae. Evenden (1926) summarized the seasonal history as follows: One generation occurred per year. Eggs were laid in August in rows on needles where they overwintered. Eggs hatched when new needles began to appear in the following spring. Larvae matured in late July and lowered themselves to the ground on silken threads where they pupated on various objects. Adults emerged in 15-20 days and immediately mated and began laying eggs.

He also marked 100 representative trees in 1924 and examined them until 1933. Of 84 severely defoliated trees, 12 died from defoliation alone and 14 died from a combination of defoliation and infestation by the western pine beetle. No mortality occurred in moderately or lightly defoliated trees. Eighty-nine percent of the study trees failed to add any basal increment for 1 - 11 years (Ave 2.6 years).

Among photos in the WFIWC archives is one of F.C. Craighead beside one of Evenden's study trees near New Meadows, June 1922. He had just succeeded A.D. Hopkins as Chief of the Division of Forest Insects, USDA, Bureau of Entomology, and was making his first trip west in that capacity. I have seen numerous photos of "F.C." and note that he never looked at the camera and always wore leggings in the field probably as protection against snake bite. His attire and demeanor were so characteristic that I was able to identify him in a photo of the Tenaya "Ghost Forest" in Yosemite N.P. I had wondered who the person was for many years.

Boise National Forest, Idaho, 1953-54. An outbreak occurred in ponderosa pine on the Boise N.F., Idaho, in 1953 involving 169,000 acres. The area was sprayed in 1954 with DDT in fuel oil at a rate of 1 lb of DDT per gallon of oil per acre. The project entomologist was Leslie W. Orr, stationed at Ogden, UT. He and other employees of the Div. of Forest Insect Investigations had been transferred to the Forest Service when the Division was dissolved in Dec. 1953. He transferred to New Orleans soon after the project. I know of no detailed record of this infestation but I was stationed at Idaho City in charge of a spruce budworm control project in 1955 and saw no effect of the outbreak, due apparently to effectiveness of the DDT treatment. -- Malcolm M. Furniss

References

Aldrich, J.M. 1912. Note on Theronia fulvescens. Jour. Econ. Entomol. 5: 87-88.

Aldrich, J.M. 1922. Letter to Reginald Barker, Boise, ID, Sept. 30, 1922 recollecting the 1896-98 outbreak and regarding pine butterfly seasonal history. (WFIWC archives).

Dewey, J.E., et al. 1974. Mexacarbate and Bacillus thuringiensis for control of pine butterfly infestation-Bitterroot National Forest, Montana--1973. USDA For. Serv., Division of State and Private Forestry, Rpt. 74-10, 25 pp. illus.

Evenden, J.C. 1926. The pine butterfly, Neophasia menapia Felder. Jour. Agric. Res. 33(4): 339-344.

Evenden, J.C. 1940. Effects of defoliation by the pine butterfly upon ponderosa pine. Jour. Forestry 38(12): 949-955.

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