DOUGLAS FIR PITCH MOTH. PA 
will emerge, 3 generations, those of the issues of 1918, 1914, and 1915, 
may be located and destroyed at one time. However, no matter how 
close the examination, a few infested pitch tubes will always escape 
notice. It is therefore advisable that the same area be scouted 
several times in the course of each season. After an area is once 
cleared it should not be a difficult task to keep the insect in check and 
much the less so if control projects cover big sections.* 
Destruction of the larva is the only remedy that can be used to 
reduce an infestation. When the infested pitch tube is located, it 
should be separated from the tree, the thus exposed larva killed, and 
to insure cleaner healing the ragged edges of the wound should be 
smoothed with a knife or small ax, after which they should be painted 
with creosote or a similar preparation, to prevent reinfestation by 
insects or fungi. The enlarging of the wound by the smoothing of 
its edges will also leave a pitch blister in the tissues, but the ultimate 
result will not be nearly as disastrous as from the untreated sesiid 
wound, since a clean healing from the inside obviates much of the 
chance of its producing a circular seam. Freshly vacated wounds 
might be treated the same way with profit. 
SUMMARY AND CONCLUSIONS. 
That the financial loss caused by Sesia novaroensis in Douglas fir 
product is great and represents a greater leak in profits to manu- 
facturers than any other avoidable item is evident. 
That the depreciation for which this age is taxed can be eliminated 
for the benefit of posterity at an expense so low that it is but a 
fraction of that which the damage represents seems to be sufficiently 
demonstrated by the results of the investigations and experiments. 
The manufacturer will always bear the greater extent of the loss, 
and the manufacturing interests should inaugurate the elimination of 
the insect by putting into effect a policy of paying better prices for 
timber where it is clear of pitch seams and reducing the price com- 
mensurately for material where logs are defective to an appreciable 
extent, instead of paying a uniform amount of so much per thousand 
feet in a locality, without consideration of existing conditions. This 
would create among owners of forest lands a stimulus to produce clear 
timber, free of pitch seams, by a little attention annually, and even 
if the immediate desire should be merely the obliteration of the 
evidence on young trees by which the defect in the merchantable 
material is determined, for the purpose of deceiving the lumber 
cruisers, it would nevertheless produce the desired end. 7 
1 Under ‘“ Habitat”’ and “ Host Trees and Character of Injury” is suggested where to 
look for infested trees. 
