128 
Journal of Agricultural Research 
Vol. XXI, No. 3 
During the summer of 1911 Forest Pathologist Dr. E. P. Meinecke 
made a reconnaissance through the Tenaya Basin and Tuolumne Meadows 
and reported widespread infestation by a needle-miner and a heavy 
flight of moths which occurred in July and August of that year. 
In October, 1912, Mr. J. M. Miller made a trip into the Tenaya Basin 
and on into the Tuolumne Meadows and found that the barkbeetle 
infestation reported by Mr. Burke had spread and was threatening the 
lodgepole pine stands in both the Tenaya and Cathedral Basins. At the same 
time the infestation of the lodgepole pine needle-miner was conspicuous 
in both watersheds. At that time the insect was in the larval stage in 
the needles of the host, having mined such a high percentage of them that 
the foliage cast of the entire forest presented a dull brownish color. The 
general effect was suggestive of the scorching resulting from fire. Sub¬ 
sequent examinations by Mr. Miller in 1913 and 1914 indicated that the 
infestation of the insect was distributed throughout about 30,000 acres 
in the National Park, extending through the main Tuolumne Watershed 
and the upper basin of Tenaya Creek, a tributary of the Merced. It was 
limited, however, to lodgepole pine growing between the elevations of 
7,000 and 9,000 feet. Where the infestation had been prevalent for 
several years, the stands were usually defoliated to a considerable degree. 
Adult specimens collected by Mr. Miller in 1913 were later described as a 
new species, Recurvaria milleri , by Mr. August Busck. 1 
The writer was assigned in 1917 to a special study of the insect by his 
immediate superior, Mr. Miller. 2 The program of the work as outlined 
at that time consisted of field studies and experiments to be conducted 
throughout the period of activity of the insect in the infested areas 
during the spring and summer of 1917, 1918, and 1919. This original 
outline was not changed, and the investigations were carried out in con¬ 
nection with the studies of a barkbeetle which infests the host tree in 
the same locality. 
During the early summer of 1918 Mr. Carl Heinrich, specialist in 
forest Eepidoptera of the Bureau of Entomology, accompanied the 
writer on a field trip into the infested areas. 3 
CONDITION OF INFESTED STANDS 
Where the needle-miner has been prevalent, the first noticeable result, 
aside from the brownish cast of the foliage caused by the color of the 
affected needles, is a distinct phase of defoliation. This is caused by the 
falling of a very high percentage of the needles which have been attacked. 
After several years of repeated defoliations a noticeable dying of the 
crowns and ends of branches, a stunting of growth, and a general decadent 
1 Busck, August, descriptions op new microlepidoptera op forest trees. In Proc. Ent. Soc. 
Wash., v. 16, no. 4, p. 143-150, pi. 7-8. 1914. 
3 Studies and records made by Mr. Miller in 1913 and 1914 have been freely used by the writer as a basis 
for his investigations, and acknowledgment is made of the value of these first records. 
3 Suggestions made by Mr. Carl Heinrich at the time of this trip and subsequent assistance in the deter¬ 
mination of material sent to him have been of great help to the writer. 
