December, ’20] 
HERBERT: WASHING FOR ELM SCALE 
473 
The trunk and each branch and twig were hit with a solid stream of 
water, most of them receiving it from three directions. 
The results obtained were highly satisfactory and these trees re¬ 
mained clean until early fall when young scales from nearby trees 
crawled onto them to hibernate. Some of the gardeners tried this 
out upon a number of young elms, but their results were less satis¬ 
factory apparently because they were willing to simply wet the trees 
instead of seeing that a forceful stream hit every branch and crevice 
from several directions. 
On Medium-Sized Trees 
It was found by using a 12-foot platform and a 7- or 8-foot extension 
rod that trees between 35 and 40 feet high could be reached, but since 
most of the trees had attained a height of 60 to 90 feet, the idea of 
using this was abandoned. However, one 40-foot tree was washed in 
this way on April 26, 1918, and was found to be only moderately suc¬ 
cessful. It proved to be quite tedious work, 1 hour and 40 minutes 
being required to carefully cover the tree. One year later the tree 
was apparently infested as badly as ever. 
On Large Trees 
The next problem which arose was how to obtain a greater pressure 
and volume of water so as to reach the tops of the larger trees. This 
was finally settled by the city of San Jose offering the use of water 
from their large mains and the loan of a steam fire engine. With the 
use of these the question of pressure and volume of water was com¬ 
pletely solved. 
Aside from the engine, the apparatus consisted of 1,000 feet of 21- 
inch hose, a short tapered nozzle with a circular J-inch opening, and a 
stand E to facilitate holding the nozzle. In spite of its name, this is a 
T-shaped iron bar, the lower end of which is pointed to stick in the 
ground. The hose is strapped to the upright piece, while the crossbar 
serves as a handle to be used in directing the stream. This is a very 
necessary part of the equipment and probably without it the crew 
would have refused to hold the nozzle for several days in succession. 
As the engine stood for a long time in one place no method of pro¬ 
pulsion was furnished with it, but it was hooked to the rear of the 
gardener’s one-horse wagon when moving was necessary. 
At first, a pressure of 100 to 120 pounds to the square inch was 
maintained and later increased to 160 pounds. This threw a strong 
stream well above the treetops without doing any harm. In fact it 
was beneficial, giving the trees a good cleaning by removing all of the 
dead twigs and branches, besides incidentally giving the trees and 
