DUSTING AND SPRAYING EXPERIMENTS 



OF 



1918 AND 1919 



BY W. C. BUTTON 



INTRODUCTORY 



This bulletin contains reports of the results of a series of dusting 

 and spraying experiments conducted by the Horticultural Section dur- 

 ing the seasons of 1918 and 1919. This work included comparisons of 

 dusting materials, lime-sulphur solution, bordeaux, dry lime-sulphurs, 

 lead arsenate, calcium arsenate and magnesium arsenate. These mater- 

 ials were used on apples, cherries, plums, peaches, currants and pota- 

 toes. 



EXPLANATORY NOTES 



The meaning of several terms used may not be familiar to all. To 

 avoid repetition, the following explanations are in order: 



DUSTING TERMS 



90-10 mixture. A dusting mixture containing 90% dusting sulphur 

 and 10% dry lead arsenate. 



85-15 mixture. One containing 85% sulphur and 15% lead arsenate. 



3 in 1 dust. A mixture containing sulphur, tobacco dust and lead 

 arsenate. 



50-40-10 mixture. One containing 50% sulphur, 40% filler (usually 

 hydra ted lime) and 10% lead arsenate. 



Concentrated dust. A mixture containing only sulphur and lead 

 arsenate. Usually made by the 85-15 or 90-10 formula. 



Dilute dust. A mixture containing 40 to 50% sulphur, 35 to 50% 

 filler (hydrated lime, talc or gypsum) and 10 to 15% lead arsenate. 



SPRAYING TERMS 



1 to 40. This refers to lime-sulphiy of 31 to 33 degree Beaume test 

 used at the rate of 1 1 4 gallons in .~0. 



4-4-50 bordeaux. This refers to bordeaux made of 4 pounds stone 



