FORTIETH ANNUAL REPORT. 151 



aud has been universally used ou grapes, i)otatoes aud other crops. In 

 recent years, however, there has developed a very serious objection to the 

 use of Bordeaux mixture as a fungicide on apples, owing to the injurious 

 effect it produces on both fruit and foliage. The fruit of many varieties 

 like the Ben Davis and Jonathan becomes russeted and often dwarfed 

 and distorted from the toxic action of 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 tliat time having become tougher and 

 more resistant. The skin of the young fruit is injured by the copper 

 and as the apple develops, the injured portions enlarge, resulting in 

 russet blotches and streaks. In Avet seasons the russeting of the fruit is 

 sometimes so serious as to reduce its market value 25 per cent, or in 

 ^ome cases even 5(1 per cent. 



The jvathologists and apple growers have, therefore, been driven to 

 seek a less caustic fungicide and the result has been the development of 

 various lime-sulphur preparations. During the ])ast four years the 

 Bureau of Plant Industry, and some of the experiment stations, have 

 been conducting experiments with lime-sulphur fungicides and the re 

 suits luwe been such as to warrant the recommendation of dilute lime- 

 sulphur solution as a substitute for Bordeaux mixture in a larg^ part of 

 the apple spraying operations. 



THE LIME-SULPHUR SPRAYS. 



For two or three decades a preparation known as the lime-sulphur 

 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 sjn-ay ai)plied to peach trees in the early spring two or three weeks 

 before they blooin would prevent -peach leaf-curl, and it is now a com- 

 mon practice to spray for scale and leaf-curl at the same time, using the 

 lime-sulphur wash. The Hme-sulphur solution, now rapidly coming into 

 use as a summer spray for apples, is only a modification of the old lime- 

 sulphur wash. 



Homc-Made TAme-^}ilpliur Solution. — Concentrated lime-sulphur so- 

 lution to be diluted and used as a summer spray on apples may be pre- 

 pared as follows : Boil sixteen i>ounds of sulphur and eight pounds of 

 lime with about ten gallons of water for forty-five to sixty" minutes, 

 finishing wath eight gallons of concentrated solution. Tlien strain and 

 dilute it with water to make 200 gallons of spray. This makes four 

 pounds of sulphur in each fifty gallons of spray, which, in our experi- 

 ments, has proved to be about the right strength for summer spraying of 

 apples. It may be made in larger quantities by using 100 ])ounds of sul- 

 phur and fifty pounds of lime and boiling them together for forty-five to 

 sixty minutes, using enough water to fiinish Avith fifty gallons of con- 

 centrated solution. The boiling may be done in a kettle over a fire or in 

 a barrel or other tank Avith steam. A seventy-five gallon feed cooker is 

 perhaps the most satisfactory equipment. 'In diluting for summer 

 spraying two gallons of this solution should be used in fifty gallons of 

 water. Used at this strength in our experiments it controlled apple 

 scab, leaf-spot and cedar rust fully as Avell as Bordeaux mixture. Avithout 

 seriously injuring the fruit or foliage. 



