No. 6. DEPARTMENT OF AGRICULTURE. 689 



FUNGOUS DISEASES OF ORCHARD TREES AND FRUITS. 



By M. B. WAITE, Pathologist in Charge of Orchard Diseases, 

 United States Department of Agriculture. 



SPRAYING MIXTURES. 



It will not be possible for me to explain the method of prepara- 

 tion of all the spraying mixtures that have been used in the treat- 

 ment of all the diseases which affect our fruit trees. I will therefore 

 take up two of the leading mixtures used in the orchard and a few 

 of the fungus and other diseases. 



There are two preparations that stand our prominently as by far 

 the best of all that are used in treating the orchard. The lime- 

 sulphur-salt mixture is the best for spraying the trees while they are 

 dormant, up to the time the buds have begun to swell in the spring. 

 The Bordeaux mixture, especially if combined with an arsenite, is 

 the best for spraying the trees when they are in foliage and fruit. 



THE LIME-SULPHUR-SALT MIXTURE. 



The formula varies for this considerably as used by different 

 people in different sections. The mixture is so good that almost 

 any combination of sulphur and lime properly boiled together, 

 usually answers the purpose for which it is intended. We have 

 adopted as our standard formula, however, 15 pounds of flour or 

 flowers of sulphur, 20 pounds of high grade stone lime, 10 pounds 

 of salt, to 50 gallons of water. The sulphur should be mixed with a 

 little water in the form of a paste. About 10 gallons of water should 

 be brought to a boil, or nearly so, the lime added and then the sul 

 phur and salt all practically together. If the lime is not pure high 

 grade stone lime the amount should be increased so as to give the 

 equivalent of pure lime. We have used partially air slaked lime 

 with success, provided we increased the quantity. The mixture can 

 be boiled in an iron kettle or better, by means of steam conducted 

 through a pipe into a barrel or cask. While boiling the rest of the 

 water should be added. This spray should be applied warm and 

 mixed up immediately before using. It is effective against the curl 

 leaf of the peach and against most of the apple cankers and bark 

 diseases of fruit trees. It kills the spores of pear leaf blight, appl< j 

 scab, the Monilia fungus and other things of that sort and retards 

 the first appearance of these diseases but does not prevent summer 

 attacks of them on the new growth. Furthermore it is the best 

 known remedy against the San Jose" Scale and certain other insect 

 pests, so that it combines to a remarkable degree the fungicidal and 

 insecticidal effect. It can not be used after the leaves are out, 

 except possibly as a wash to apply directly to the trunks, as it injures 

 foliage. 



BORDEAUX MIXTURE. 



The best all around fungicide for use on fruit trees is the Bordeaux 

 mixture. There are various formula? for making up this mixture and 

 various methods of mixing. I can give only the essential points. 



