16 
BULLETIN 1439, U. S. DEPARTMENT OF AGRICULTURE 
The pump used was of the ordinary barrel type, having two paddles 
at the bottom as an agitator. After the water and the arsenate of 
lead had been mixed in the barrel the oil was added and the whole 
agitated for five minutes. The mixture was allowed to stand for 
one hour. Most of the oil was taken up by the arsenate of lead, but 
a small quantity of free oil arose to the surface. The pump was 
then started and the spray applied. The material spread well over 
the foliage. The plots were examined on October 1, 47 days after the 
spraying, more than 10 inches of rain having fallen in the meantime. 
It was estimated that not over 15 per cent of the originally adhering 
material in the linseed-oil plot and 20 per cent of that in the fish-oil 
plot had been washed 
off, and no injury was 
noted on any of 
foliage (fig. 12). 
the 
ADHESIVES INJURIOUS 
TO FOLIAGE 
LEAD OLEATE 
As has been pre- 
viously mentioned, 
lead oleate was applied 
at Saugus, Mass., June 
12, 1924. On June 14 
a light drizzling rain 
fell, lasting the entire 
day, but the precipita- 
tion was slight, the 
total being less than 
one-fourth inch. On 
June 18 the writer had 
occasion to visit the 
plots, and in going 
through that sprayed 
with lead oleate found 
that the foliage on the 
gray birches, the wild 
cherry, and some of the 
undergrowth was badly 
burned; some of the oak foliage was less severely burned. The 
foliage in the other six plots was carefully examined, but no signs 
of burning could be found on any of it. 
On June 20 this plot was again examined, and burning was found 
on gray birch, red oak, black oak, and scrub oak, and on the under- 
growth, such as blueberry, brake ferns, and false Solomon's seal 
(fig. 13). On June 26 more burning was noted in the plot, some of 
the oak trees being burned so badly that a large proportion of the 
foliage had withered and dropped to the ground. On July 22 more 
burning was noted. At this time it was estimated that 70 per cent 
of the spray had been washed off, and thereafter, until the end of the 
season, the injury did not seem to increase. 
Fig. 12.— Appearance of foliage in plot at Saugus, Mass., 47 days 
after application of spray mixture containing fish oil as adhesive; 
the foliage had meanwhile been exposed to 10 inches of rainfall 
