184 
Resin-wash kerosene emulsion diluted 7 times: About 2 per cent of the eggs 
hatched, the others dead or shriveled and changed in color, and will undoubtedly 
die. 
Resin- wash was applied to an old tree blackened with smoky fungus to test" 
whether it would free the tree of this discoloration and at the same time act on the 
eggs of the Psylla. The effect in the latter direction was unimportant, most of the 
eggs hatching, and are now developing uninjured. The smoky fungus also does not 
seem, at this date, to have been materially lessened, although it is showing some 
little indications of breaking off and peeling where it was most abundant. 
The above series of sprayings supports, to some extent, the results 
obtained by Mr. Slingerland, but are more satisfactory. It is possible 
that Mr. Slingerland's observations were not continued long enough to 
determine the actual facts as to the effect on the eggs, the results of 
these experiments only reaching any definiteness after eight or ten days. 
The results obtained with the stronger washes mentioned are the only 
ones of any value, and as none of the applications harmed the trees in 
the least, it will be feasible to spray with the emulsions diluted as little 
as with 7 parts of water. In every case, however, a number of eggs 
escaped destruction, while even with the weakest washes the larvae 
were invariably killed. Spraying has, of course, no value against the 
adults during their active summer existence, because they are compara- 
tively shy and at the first disturbance fly to other trees. 
REMEDIAL TREATMENTS ADVISED. 
In view of the experience gained by Mr. Slingerland, and the above 
series of experiments, it seems to me that the larval periods in the life- 
cycle of the Psylla are particularly vulnerable, and the first of these 
especially so, occurring as it does at a time when spraying can be most 
economically and efficiently pr cticed. Spraying to reach the mid- 
summer broods of larvae when the trees are in full fruit is more or less 
impractical, but may sometimes be advisable, particularly with young 
orchards. The following treatments are therefore recommended : The 
first is a spring application which should be made immediately after 
the leaves are well unfolded and the eggs, deposited by the hibernating 
individuals, are hatched. A thorough spraying at this time with kero- 
sene emulsion diluted to the normal strength with 9 parts of water, 
or, if applied earlier, before the eggs are all hatched, with 7 parts of 
water, will, it seems to me, effect the destruction of practically all the 
eggs and larvae. Treatment at this time is especially recommended on 
account of the fact that it coincides with the periods for first or per- 
haps the second application for the leaf blight of the pear, and the kero- 
sene emulsion and Bordeaux mixture may be combined in one applica- 
tion with little additional trouble or expense. The experiments already 
conducted show the complete feasibility of this combination, which, 
briefly, consists in using Bordeaux mixture in lieu of water as a diluent 
for the emulsion. 
A second treatment which promises well is the winter spraying for 
the hibernating adults. A thorough wetting of the trunk and limbs 
