REPORT OF THE SOCIETY 17 



Reference has already been made to the peciiHar conditions in Nova Scotia, 

 which compelled the fruit growers to retm'n to a modified form of Bordeaux 

 where lime is used in excess. In 1919 they used the 3 :10 AO and the 2 :10 :-40 

 formulae with gratifying results. 



Dust Spraying 



While dust spraying was probably employed before liquid spraj-ing, it was 

 superseded by the latter when Bordeaux mixture and Paris Green became the 

 standard spraying materials. However, as fruit growing was developed more 

 extensively, and intensively as well, the factors of economy of time and cost of 

 equipment in spraying operations assumed more importance, and efforts were 

 made by the more progressive men to meet the needs of the industry by devising 

 more economical methods of spraying. 



About 20 years ago sulphur dusting was tried occasionally on grapes, but 

 about 1911 orchard experiments in dusting were begun in New York State by 

 Cornell Station. These were continued for about seven years or until it was 

 conclusively demonstrated that dusting was both efficient and prac^ticable, and a 

 satisfactory substitute for liquid spraying. 



Xova Scotia furnishes an interesting example of changing methods in 

 spraying, due to the investigations by ^Messrs. Sanders, Kelsall and Brittain. 

 These gentlemen have devised improved mixtures for both liquid and dust 

 spraying. Up to 1912 Standard Bordeaux was the fungicide used by the fruit 

 growers ; then lime-sulphur was substituted. When this proved unsatisfac- 

 tor}- a modified Bordeaux with an excess of lime was employed. 



Dusting was introduced about 1916, and gradually made headway with 

 improvements in the manufacture of dust products. In 1918, 1919 and 1920 

 the 90-10 sulphur arsenic dust (90 per cent sulphur and 10 per cent lead arsenate) 

 and copper arsenic dust (10 per cent copper sulphate, 5 per cent arsenate of 

 lime, and 85 per cent hydrated lime) were used. In 1921 both the sulphur and 

 the Bordeaux methods will be used by the fruit growers of that province. 



Up to 1920 no dusting material has been found that controlled sucking 

 insects satisfactorih', but the 1920 experiments in California against the Pear 

 Thrips, with 5 per cent "Xico dust"' which contains 5 per cent Black Leaf 40 

 and pulverized Kaolin, and those in Xova Scotia against psyllids with nicotine 

 sulphate with sulphur and arsenate of lead, give strong hopes that the difficulty 

 has been largely overcome. It will be possible for the future to use a 3— in— 

 1 combination dust against fungi and biting and sucking insects. 



5175—2 



