Historical 



mixture. In 1886 the spraying campaign may be said to 

 have been well started in this country. 



The disinfection of seeds by bluestone was practiced first 

 with the cereals as early as 1807 by Prevost of France, and 

 improved by Dreisch in 1873, by the addition of a limewater 

 bath to follow the bluestone. In 1887 Jensen of Denmark 

 improved upon these methods by developing his hot-water 

 treatment, which has since proved 

 of great value, not so much for its 

 primary use, in which it has been 

 superseded by formalin, but owing to 

 its applicability to those loose smuts 

 which cannot be successfully treated 

 by surface disinfection. Similar seed 

 treatments have been extended to 

 the potato by Bolley, arid to cabbage 

 by Harding. 



The production, by breeding, of 

 new and disease-resistant varieties is 

 one of the latest and most promising 

 methods of combating plant diseases. 

 Grapes resistant to Phylloxera were 

 produced by Millardet; cotton, cow- 

 peas, and watermelons resistant to 

 wilt by Orton; cabbage by Jones; 

 tomato by Durst and others; tobacco 

 resistant to Thielavia by Johnson. 



No small part in the progress that 

 has been made in the prevention of 

 plant disease is due to the improve- 

 ment of appliances, dusters, pumps, nozzles, etc., for dis- 

 tributing the disinfectants upon the plants. This progress is 

 well illustrated by comparing the broom of Millardet with 

 the knapsack, barrel, or power sprayer of to-day. 



Fig. 3. — An improved 

 brush for distributing 

 Bordeaux mixture. 

 After Lodeman. 



