METHODS NOW USED IN FIGHTING THE GIPSY MOTH. 69 



COST OF METHODS EMPLOYED. 



In the gipsy moth work it is very necessary to know the approxi- 

 mate cost of cleaning up or caring for any given infested area. The 

 treatment work attempted by the Bureau has been principally 

 along the line of caring for trees growing near wooded roadsides, 

 while that of the States has covered infested areas of all kinds. In 

 the latter work, especially in woodland areas, much money has been 

 expended in thinning out the trees and putting the forests in the 

 best possible condition, so that the moth can be successfully treated. 

 Special attention has been paid to leaving trees which would be the 

 most profitable, and also those which are to some extent immune 

 from the feeding of the insect. 



Mr. L. H. Worthley, assistant forester in charge of moth work for 

 the State of Massachusetts, who has had wide experience in cutting- 

 out operations, states that woodland can be properly thinned (not 

 pruned) and put in condition for treatment measures against the gipsy 

 moth at a cost ranging from $15 to $35 an acre. This variation 

 depends on the character and size of the trees to be cut. The first 

 roadside work done by this office where considerable heavy timber was 

 cut cost about $40 an acre for thinning, burning, pruning, and creosot- 

 ing egg clusters. As the force of men became more experienced in the 

 work it has been possible to reduce the expense of cutting out these 

 roadside strips. The average cost of work on over 30 miles of 

 strips last fall amounted to $27.50 an acre. It may seem at first 

 glance as though this method required an excessive expenditure of 

 money; nevertheless it should be stated that the gipsy moth can not 

 be successfully controlled unless the woodland is properly thinned 

 and dead wood removed. In addition to this, if hollow trees are 

 allowed to remain it is almost impossible to keep the insect in sub- 

 jection. Another feature which should be pointed out is that 

 although the first expense of cutting is large, the cost of caring for 

 the area in future years is greatly reduced. Our data show that as 

 a result of putting the roadsides in good condition for future treat- 

 ment it has been possible to reduce the amount each year which must 

 be expended for destroying the caterpillars and egg clusters. 



Many experiments have been carried on for the purpose of decreas- 

 ing the cost of spraying work. The adoption of the water tower 

 on the tanks has materially assisted in this direction. A careful 

 record of the spraying this year shows that over 360 miles of roadway 

 were sprayed on both sides. By taking into account the entire cost, 

 including labor, poison, supplies, fuel, and a liberal allowance for 

 depreciation on the outfits used, it should be possible to spray road- 

 sides for about $2 an acre. 



