very good satisfaction. In Maryland, with this insect, it has proved 
necessary to use the wash at 6 times the summer strength to destroy all 
of the well-protected hibernating scales; and with: other scale insects 
much stronger mixtures than those used in California have, in the east, 
proved ineffectual. For regions, therefore, with moderately severe win- 
ters, the use of the resin wash to destroy hibernating scale insects seems 
inadvisable. 
TIME TO SPRAY FOR SUCKING INSECTS. 
For the larger plant bugs and the aphides, or active plant lice, and 
all other sucking insects which are present on the plants injuriously for 
comparatively briet periods, or at most during summer only, the treat- 
ment should be immediate, and if in the form of spray on the plants, at 
a strength which will not injure growing vegetation. 
Tor seale insects and some others, as the pear Psylla, which hiber- 
nate on the plants, two or more strengths are advised with most of the 
liquid insecticides recommended, the weaker for summer appligations 
and the more concentrated as winter washes. The summer washes for 
scale insects are most effective against the young, and treatment 
should begin with the first appearance of the larve of the spring or 
any of the later broods, and should be followed at intervals of seven 
days with two or three additional applications. The first brood, for 
the majority of species in temperate regions, will appear during the 
first three weeks in May. Examination from time to time with a hand 
lens will enable one to determine when the young of any brood appear. 
The winter washes may be used whenever summer treatment can not 
be successfully carried out, and are particularly advantageous in the 
case of deciduous plants with dense foliage which renders a thorough 
wetting difficult in summer, or with scale insects which are so irregular 
in the time of disclosing their young that many summer treatments 
would be necessary to secure anywhere near complete extermination. 
In the winter also, with deciducus trees, very much less liquid is 
required, and the spraying may be much more expeditiously and thor- 
oughly done. In the case of badly infested trees, a vigorous pruning 
is advisable as a preliminary to treatment. 
All of the washes mentioned are excellent as summer remedies. As 
winter washes for temperate regions the kerosene mixtures and whale- 
oil soap solutions, particularly the latter, have so far given the best 
results. These stronger mixtures may be applied at any time during 
the dormant period of vegetation, and, with deciduous trees, preferably 
immediately after the falling of the foliage. Inthe growing season any 
of these stronger washes would cause the loss of foliage and fruit, and 
the more concentrated probably the death of the plant. 
THE GAS TREATMENT. 
Hydrocyanie Acid Gas. 
The hydrocyanic acid gas treatment of scale-infested trees, until 
recently exclusively confined to California, has, within the last year, 
been introduced in the East by the Department to combat the San José 

