12 
BULLETIN 1439, U. S. DEPARTMENT OF AGRICULTURE 
Arsenate-of-lead mixture, without the addition of special adhesive, 
did not spread well over the foliage, especially the oaks, and very 
little, if any, would adhere to the new growth on white oaks. The 
spraying of this mixture was done on a partly cloudy day at a tem- 
perature of 70° F. (fig. 11). 
EXPERIMENTS WITH CONIFEROUS TREES IN NEW JERSEY 
As already stated, a 9-acre tract of solid blue spruce was chosen 
for testing the various adhesives when sprayed on the foliage of 
coniferous trees. The foliage on the blue spruce trees was very 
thick, and it was found necessary to use a spreader on the spraying 
nozzle, and to force the spray in between each tier of branches. 
Both the new foliage of the season and the older foliage were observed. 
The various adhesives were mixed with the arsenate-of-lead mix- 
tures in the same manner as in the experiments with deciduous trees. 
Fig. 11.— Appearance of foliage in plot at Watchung Ridge, sprayed with arsenate-of-lead mix- 
ture without the addition of special adhesive. A, foliage shortly after application of spray, June 
9, 1924; B, foliage on September 17, 1924 
The proprietary miscible oil, which had been tried in the experi- 
ments with deciduous trees, was not used with coniferous trees. 
No special plot was laid out for experimenting with soap, as large 
areas of spruce throughout the park were being sprayed with arsenate- 
of-lead mixture containing it. In all cases the spray spread well 
over the old foliage but not so well over the new growth. 
The fish oil spread well over the old foliage but not quite so well 
over the new growth. On the latter, however, it was just as good as 
soap, if not a trifle better. The mixture containing it was sprayed 
on a partly cloudy day with a light wind and a temperature ranging 
from 65° to 70° F. 
The linseed oil spread well, about as did fish oil, over the old growth. 
The day of spraying was partly cloudy, with a light wind and a tem- 
perature of 68° to 72° F. 
The corn oil did not spread so well over the foliage as did fish oil 
and linseed oil. When the spraying was done the weather was 
cloudy, with a temperature of 60° F. 
