50 



the copper in the Bordeaux. This injury is produced mainly 

 by the applications made within three or four weeks after 

 the blossom petals fall and is especially serious in a wet 

 spring. Midsummer or late spraying, such as required for 

 bitter-rot, rarely russets the fruit, the skin at that time hav- 

 ing become tougher and more resistant. The skin of the 

 young fruit is injured by the copper and as the apple de- 

 velops the injured portions enlarge, resulting in russet 

 blotches and streaks. In wet seasons the russeting of the 

 fruit is sometimes so serious as to reduce its market value 

 25 per cent, or in some cases even 50 per cent. 



The pathologists and apple growers have, therefore, 

 been driven to seek a less caustic fungicide and the result 

 has been the development of various lime-sulfur prepara- 

 tions. During the past four years the Bureau of Plant In- 

 dustry, and some of the experiment stations, have been con- 

 ducting experiments with lime-sulfur fungicides and the re- 

 sults have been such as to warrant the recommendation of 

 dilute lime-sulfur solution as a substitute for Bordeaux mix- 

 ture in a large part of the apple spraying operations. 



The Lime-Sulfur Sprays. 



For two or three decades a preparation known as the 

 lime-sulfur wash has been used in the dormant season for 

 the control of the San Jose scale and other scale insects. It 

 has been known for years that the same spray applied to 

 peach trees in the early spring two or three weeks before 

 they bloom would prevent peach leaf-curl and it is now a 

 common practice to spray for scale and leaf-curl at the same 

 time, using the lime-sulfur wash. The lime-sulfur solution, 

 now rapidly coming into use as a summer spray for apples, 

 is only a modification of the old lime-sulfur wash. 



Home-made Lime-Sulfur Solution : Concentrated lime- 

 sulfur solution to be diluted and used as a summer spray on 

 apples may be prepared as follows : Boil 16 lbs. of sulfur 

 and 8 lbs. of lime with about 10 gallons of water for 45 to 

 60 minutes, finishing with 8 gallons of concentrated solu- 

 tion. Then strain and dilute it with water to make 200 gal- 

 lons of spray. This makes 4 lbs. of sulfur in each 50 gallons 

 of spray, which in our experiments, has proved to be about 

 the right strength for summer spraying of apples. It may 

 be made in larger quantities by using 100 lbs. of sulfur and 

 50 lbs. of lime and boiling them together for 45 to 60 min- 



