184 



Resiu-wash keroseue tiimlsiou diluted 7 times: About 2 per cent of the eggs 

 hatched, tlie others dead or shriveled and changed in color, and will undoubtedly 

 die. 



Resin-wasli 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 eiiect 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 

 Jittle 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 ev^ery 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. Slingerlaud, 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 lirst 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 larvie 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 i^ractically all the 

 eggs and larvte. Treatment at this time is especially recommended on 

 acc(mnt 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 whicli promises well is the winter spraying for 

 the hibernating adults. A tiiorough wetting of the trunk and limbs 



