10 BULLETIX 111, TJ. S. DEPABTMEXT OF AGRICULTURE. 
Remembering -that in the comparatively small zone about Rainy 
Lake infested by the pitch moth there are tens of thousands of trees 
with heavy pitch exudation at their base which, once ignited, will 
burn for several days, rain or shine, and that during the violent 
thunder storms there many trees are struck by lightning and the 
pitch set on fire, we will have the combination which explains the 
frequency of fires in that area. 
Let us illustrate. Lightning strikes a tree infested by Vespamima 
and sets it afire. During the storm the ground is soaked sufficiently 
to prevent the &re from spreading. The pitch, however, owing to its 
thickness and inflammability, continues to burn. On the following 
day a clear sky allows the sun to dry the ground cover around the 
burning pitch sufficiently so that a surface fire is started which will 
be ended by the next shower. If the stand consists of medium or 
small sized trees and the area has passed through fires before, every- 
thing is killed, and the place, when it has been reforested, will stand 
out clear in the checkerboard of forest and elemental battles even 
after half a century or more, as is the actual case in this territory. 
As storms are evidently quite frequent there, the patches burned 
are usually small, ranging from 50 to 200 acres. However, there are 
also some burns which an accumulation of debris had undoubtedly so 
augmented that whole sections were swept. All the traceable evi- 
dence m the biggest burn in the area points to insect work as the 
primary cause, just as in the smaller burns where the evidence is 
more definite and is easier of location. 
With a knowledge of these facts, one can not but conclude that the 
peculiar results of the work of Vespamima sequoia are the chief and 
primary contributing cause of the frequency, we might almost say 
continuity, of fire damage to forest growth in this area. To eliminate 
or ameliorate this condition, it is manifestly necessary to eliminate 
the insect or at least reduce it to such an extent that it loses its 
menacing aspect. 
REMEDY. 
Since nature and its agencies are powerless in the control of this 
insect, the scourge has to be combatted by man through direct action 
if it is not to continue its injurious activity in the future as it has in 
the past. There is only one way to reduce the insect, and that is to 
destroy it while it is in the larval stage. 
As is apparent from the portion of this bulletin relating to the life 
history of the moth, larvae can be found in the infested trees at any 
time of the year. 
However, in order to destroy the greatest number of them with the 
same amount of effort, operations should be conducted during the 
months of September to June, inclusive, when there is no snow on the 
