882 



Spraying Experiments. 



[FEB, 



"russeted" or "rusty"), that an efficacious spray harmless 

 to apple foliage and fruit is badly needed.* In America 

 the same problem confronts the apple-grower. The foliage 

 of some of the varieties of apples cultivated in that country, 

 e.g. the "Newtown Pippin," is so susceptible to injury from 

 Bordeaux mixture that 80 per cent, of the leaves may fall; 

 while the fruit of other varieties, e.g. "Ben Davis," suffers so 

 greatly from injury when Bordeaux mixture is used that this 

 spray has had to be abandoned. 



A further need in this country for a new fungicide — which 

 may possibly be supplied by a lime-sulphur wash — exists in 

 connection with the control of the American gooseberry- 

 mildew. When the "summer stage" of this mildew begins 

 to appear in May or June, the disease will, under favourable 

 weather conditions, spread through the plantation at a rapid 

 rate (just as the closely-related hop "mould" does through 

 the hop garden) unless spraying is carried out. It has been 

 well established by scientific experiments that a wash made 

 of "liver of sulphur" (polysulphides of potassium) is tho- 

 roughly efficacious in killing the mildew in its summer 

 stage and so preventing its spread, but in order to achieve 

 this result the wash has to be applied every ten days (and 

 oftener if it rains) throughout the growing period of the 

 gooseberry bush. As the weather is very frequently showery 

 at the time when the mildew is appearing, the repeated spray- 

 ings with the "liver of sulphur" wash (which is removed 

 by rain) necessary to prevent the disease spreading, may 

 make the operation too expensive for the commercial goose- 

 berry-grower. A sulphur-wash which is not readily washed 

 off by rain is required. 



Lime-sulphur washes for summer use as fungicides may 

 be divided into two classes: (1) the "self-boiled" lime- 

 sulphur wash; (2) the "factory-boiled," or "home-boiled," 

 lime-sulphur wash. 



A "self-boiled" lime-sulphur wash which has been used 

 with some success in the United States is made as follows : 

 place 8 lb. of quicklime in a 50-gallon barrel, and pour two 

 or three gallons of boiling water over it. Stir 8 lb. of 



* See the article " Injury to Foliage by Bordeaux Mixture," in this Journal for 

 May, 1 9 10. 



