1910.] Lime-sulphur Wash for Use on Foliage. 185 



regard to this point. Healthy young hop-plants were chosen, 

 and one half of some of the leaves was treated with the lime- 

 sulphur wash. Spores (conidia) of the hop-mildew were then 

 sown on both the treated and untreated halves of each leaf. 

 In no case did any infection take place on the treated part 

 of the leaves, while (under the conditions of the experiment) 

 the untreated half of the leaves became virulently infected, 

 and after fourteen days bore numerous powdery patches of 

 "mould." 



In another series of experiments a number of young hop- 

 plants which were all beginning to be infested with hop 

 "mould," were divided into two sets of equal numbers, each 

 set being, so far as the eye could judge, equally affected with 

 the mildew. In each experiment one set of plants was well 

 sprayed with the lime-sulphur wash — using a Vermorel nozzle 

 on an "Eclair etame " knapsack. A fine misty spray was 

 obtained, and the leaves of the treated plants appeared, when 

 the spray had dried on them, as though uniformly dusted over 

 with a fine, whitish, closely-adhering dust. The same result 

 was obtained as in the first experiments mentioned above, i.e., 

 the "mould" died away on the sprayed leaves, and, in those 

 cases where the sprayed plants stood apart from the unsprayed 

 plants, trie "mould" did not appear on the fresh growth. 

 During the time of the experiment the "mould" continued 

 to increase on the unsprayed plants, and the fresh leaves of 

 these, as they expanded, became infested. 



In many of the above experiments frequent and heavy 

 showers of rain fell on the sprayed leaves, but did not wash 

 off the spray owing to its closely-adhering nature. There 

 are reasons for believing that this lime-sulphur wash will be 

 useful, under certain circumstances and weather conditions, 

 for combating "powdery mildews" such as the American 

 Gooseberry mildew (Sphaerotheca mors-uvae), Hop and 

 Strawberry mildew (S. Humuli), Rose- and Peach-mildew 

 (S. pannosa), Apple mildew (Podosphaera leucotricha) f 

 Cucumber mildew (Erysiphe Cic horacearum) , and Pea mildew 

 (E. Polygoni). 



A lime-sulphur wash of the same strength as that used on 

 the hop was also sprayed during May on the foliage of 

 gooseberries, and of the following- varieties of apples : — Cox's 



