DOUGLAS FIR PITCH MOTH. 19 
of the investigations and experiments (Table I) made it evident 
that to accomplish any permanent good under general forest condi- 
tions it is best to extend control over large areas. In Project III, 
for example, where the infestation is in general rather shght, col- 
lecting was done within a 5-section limit over 460 acres only, -in 
strips containing a stand of trees of a character more susceptible to 
attack, and while the destruction of the larve resulted in some 
reduction of the annual infestation. it could not in any sense be 
regarded as an important factor in reducing the ultimate deprecia- 
tion of the timber without the application of constant attention. 
TABLE I.—Countrol of the Douglas fir pitch moth: Projects and results. 
Larve collected. 
Encect Damage. eae ENOEES: Remarks. 
1913 | 1914 
I | Medium... 5 | 3,200 790 74 | To June; from August to December, Slarve: found 
| in area. Collected thoroughly. 
ERS Grd OUSESsril=e= ches oe | 30 101 5 | Thorough search. 
III | Slight....-. 5 460 94 53 | From 1913 oviposition. 
16 | From 1914 oviposition. Collected during Decem- 
ber. Collecting done in strips of reproduction 
within the mature stand. 
Nia ELC AAV; ool! == =o 40 207 9 | From 1913 oviposition. 
Wi leSerious-.22)22222 22 10 41 2 | From 1912 oviposition. 
PEON Age of stand. Local conditions. 
Years 
A LOE Oe ee Re appt eee es Surrounded by older stand; hills and flats alternating. 
JOS Ug ReciaRe occa nooe Ce eae reer Northern exposure; practically isolated, except for adjoining stand 
of mature timber. 
III | 120, with strips of reproduc- | Heavy mountain forest in a solid stand which extends for miles. 
tion from 10 to 40 years old. 
TV Es 4 Oe se Res. ome ements ce Creek bottom; flat surrounded by steep hills stocked with 10-year- 
old and younger reproduction. 
Wenge eater so aeeceuasseass Practically isolated, being surrounded by yellow-pine stand free of 
any sesiid. 
In Project I, which also covers five sections, the larvee were de- 
stroyed throughout, and during the autumn of 1914 but 8 larvee were 
found near the border of the area. In Project I a daily inspection at 
the proper period in the year along the border would be amply suffi- 
cient to protect the entire area from a serious infestation until such 
time as the trees shall have outgrown the danger stage. 
The principle of “isolating” stands susceptible to infestation 
should be the potent factor in contro] of this insect. Let us take a 
practical example of what is meant by isolation in this regard. Two 
streams, distant from each other in an air line say a couple of miles, 
run parallel from their source at the base of a mountain to the open 
farm lands, but between them is, as usual, a dividing ridge. Along 
both streams, in favorable locations, the moth is equally numerous, 
yet elimination of the moth along the entire length of one stream 
