30 Director's Report of the i 



DEPARTMENT OF ENTOMOLOGY. 



Further experiments zvith sulphur sprays for San Jose scale. — 

 The investigations of this Department for the year were largely 

 directed towards obtaining an efficient sulphur spray, which could be 

 more conveniently prepared than the lime-sulphur-salt wash. In 

 some preliminary tests conducted to this end in 1902, a wash consist- 

 ing of 33 pounds lime, i6}4 pounds sulphur, 4-6 pounds caustic soda 

 or potash, and 50 gallons of water, appeared to have this qualification 

 and proved to be the most satisfactory of the various formulae tested. 



To ascertain its value under average orchard conditions for the 

 control of scale and the prevention of plant diseases, extensive experi- 

 ments, with the cooperation of the Horticultural Department, were 

 conducted with the wash at Queens, L. I., Yorktown and Carlton 

 Station. The trees treated numbered 12 14, of which 375 are peaches, 

 287 pears, 5 cherries, 225 plums, 26 quinces and 296 large apples. 



In September an examination was rhade to determine the effects 

 of the treatment upon the scale and fruit diseases. The results upon 

 the scale were variable. In some cases the treatment affected an al- 

 most entire destruction of the insects, while in others the numbers of 

 the scale seemed to have been but little affected. This variability 

 seems to have been due to the lack of sufficient heat from the lime 

 and soda to make the necessary sulphur compounds. Owing to the 

 slight attacks of diseases in these orchards, the fungicidal value of the 

 wash was not determined, Apple scab and sooty blotch were almost 

 entirely absent. The fruit of the checks and treated trees seemed to 

 be equally free from these troubles. Peach leaf curl, while more 

 prevalent, was not sufficiently abundant to indicate the merits of the 

 wash for its prevention. 



In view of the varying results obtained, investigations are being 

 made to determine methods by which the wash may be made uniform 

 in all preparations. For the present this wash is advised only for 

 experimental purposes. As the lime-sulphur-salt wash has proven 



