6 
rain or artificial washings of sprayed trees would affect the efficiency of 
the wash, and, rather surprisingly, such washings seemed to have had 
no prejudicial effect. 
From the experience up to the present time it does not seem reason- 
able to assert from Professor Forbes’ results alone that the California 
wash is not affected by hard washing rains, especially in view of the 
tests made by the Department Chemist, and the less favorable or con- 
tradictory results obtained by other experimenters, nevertheless the 
evidence is sufficient, on the whole, to warrant the placing of this wash 
among the best of the remedies in the East against the San Jose scale. 
The work in Illinois has been supplemented by independent experi- 
ments in New Jersey, New York, Maryland, Georgia, and other States, 
and while all tests have not been successful, they seem to indicate that 
the lime, sulphur, and salt wash will, in the majority of instances, give 
decidedly good results, often destroying the scale as effectively as an 
oil or a soap application. 
HOW THE WASH AFFECTS THE SCALE INSECT. 
The action of this wash on the scale is very slow and, judging from 
Professor Forbes’ experience, it is possible that in the case of our pre- 
liminary work in Maryland in 1894, if the trees had been left for the 
summer without other treatment, the lime wash might have continued 
its effect and exterminated the scale in a much greater percentage than 
was the case in April. This wash coats the tree thoroughly, has a 
decided caustic insecticidal effect, and dissolves, to some extent, and 
loosens the scale covering, so that a large number of scales perish during 
the winter and early spring, and this action continues until the emerg- 
ing of the first brood of young. As indicated above in the quotation 
from Bulletin 30, the weakened wash remaining on the trees through 
early summer may still be strong enough to kill some of the delicate 
‘ larvee and act as a deterrent to the settling of others until they perish. 
In fact, the chief benefit seems often to come at this season. 
CAUTION IN ESTIMATING RESULTS. 
It should be remembered that the sudden increase in the percentage 
of dead San Jose scales on trees in April may not necessarily be due to 
the wash, but rather to the fact that the male insects transform to the 
winged stage in April long before the females reach full growth, and 
hence there is an appearance of a sudden increase of dead scales, the 
abandoned scale covering of the male insect still adhering to the bark. 
This may often amount to 95 per cent of the scales. In the spring of 
1902 the male scales in the Department orchard represented fully 95 to 
98 per cent of the living insects on the trees in early April. The hatch- 
ing of these, of course, gave an immediate appearance of an almost 
complete extermination of the San Jose scale on these trees. This 
