n6 



Annals of Horticulture. 



A new 

 insecto- 

 fungicide. 



The 

 " grape 

 scare." 



lime is added to render the arsenic insoluble. No evidence 

 is given that this combination is always safe and effective, and 

 there are chemical reasons for doubting its value ; and it may 

 also be said that the addition of lime is what we desire to 

 avoid, for it is the lime in the Bordeaux-arsenite combination 

 which renders the material thick and heavy, and makes it 

 nearly valueless for large trees. 



Washburn* has made a combination insecticide and 

 fungicide upon a new principle. It is a mixture of Paris 

 green, sulphide of soda, and whale-oil soap : 

 j Whale-oil soap, 10 lbs. 

 { Water, 20 gals. 



( American concentrated lye, 1 ft>. 

 b } Sulphur, 2 lbs. 

 ( Water, 1 gal. 



"When a is heated enough to become thoroughly liquid, and b has been boiled until it is 

 thoroughly mixed and dark brown, add b X.o a; then heat for half an hour and add 30 gallons 

 of water, and use at a temperature of 120 degrees Fahrenheit." 



c Paris green at the rate of i lb. to 300 gallons. 



This combination was found to lessen apple-scab, codlin- 

 moth injuries, and the woolly aphis. 



A phase of the study of plant-diseases which demands at- 

 tention, is what may be termed mycological prognostication. 

 It is quite as important in many cases to know what are the 

 probabilities that a certain disease will attack a crop, as to 

 know the direct means of combating it. The conditions of 

 weather and other environments which influence the spread of 

 plant-diseases should receive close study. When, in 1890, 

 the apple-scab was so bad in New York, growers everywhere 

 asked what were the probabilities of an attack in 1891. No 

 one could answer. But the crop of 1891 was the fairest 

 which has been grown in many years. 



One of the curious circumstances of the year was the "grape- 

 scare " in New York city. The city board of health seized a 

 small consignment of grapes from Ulster county, New York, 

 which was discolored by Bordeaux mixture. The fact was 

 given to the press, and the most exaggerated reports were 

 circulated, stating that most of the grapes in the market were 

 unwholesome. An investigation was made by the Department 

 of Agriculture, and it was found that the alarm came entirely 

 from the grapes of a very few growers, who were careless in 

 the use of the fungicide. The season was dry, and the spray - 



*Bull. 10, Oregon Exp. Sta. (April, 1891). 



