474 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
lawns a good irrigating. Even those leaves which had already unfolded 
were not torn a particle. It was reported that the capacity of this • 
outfit was over 200 gallons per minute. 
The crew consisted of one foreman to direct the work, one engineer 
to run and fire the engine and three hosemen to manipulate the heavy 
hose and nozzle. The wind caused some trouble by blowing the water 
back onto the hosemen, but this would have been of little importance 
had they been dressed in the proper clothes and had not been afraid 
of the water. 
With this apparatus and crew, 191 large trees were washed in six 
days. This is an average of 15 minutes to the tree. Each tree was 
thoroughly and systematically covered in this time from at least two 
sides, each limb being followed out to its tip. This magnificent 
head of water covered an area a foot and a half square, approximately, 
by the time it hit the tree. It seemed as though no sort of an insect 
could be still clinging to a single limb which had been hit by such a 
deluge. In fact, very few did remain on the trees and these few 
were well protected by rough bark, a crotch of a limb or some such 
obstruction. 
The cost at that time was as follows: 
1 engineer, 6 days at $6.00. $36.00 
3 hosemen, 6 days at $3.50. 63.00 
2f tons coal at $13.35. 36.71 
Actual cost. $135.71 = $. 71 per tree 
To this should be added the wages of a foreman and the cost of the 
water. These were both donated in this case but could not be counted 
on under ordinary circumstances. As this was an experiment, Mr. 
Hartman, of the Bureau of Entomology, acted as foreman to see that 
nothing was slighted. The water was very graciously donated by the 
city. Therefore to obtain the cost of the operation under the usual 
circumstances, the following figures should be added to the above: 
1 foreman, 6 days at $5.00. $30.00 
500,000 gallons water at 12 cents + per M. (sliding scale.). 63.60 
$93.60 $93.60 
$135.71 
Total..*. $229.31 
This gives an average actual cost of 71 cents per tree or a computed 
cost of $1.20 per tree, when adding the cost of water and a foreman. 
This does not include wear or rental of the machinery. One hoseman 
might be dispensed with, provided the foreman helped move the hose 
when needed, thus lowering the cost by about 11 cents per tree. 
