U. S. EXPERIMENT STATION BULLETINS. 117 



the first application when the leaves are about one-third grown and the 

 others at intervals of ten or twelve days throughout the season. 



The cost of treating full-grown standard trees with the Bordeaux mixture 

 as indicated will average from 12 to 11 cents per tree. For dwarf trees the 

 cost will range from 8 to 12 cents each. The cost of treating with the ammo- 

 niacal solution will be considerably less, probably not exceeding ten cents 

 for standard and 8 cents for dwarf trees. In the nursery pear seedlings 

 can be treated six times with the Bordeaux mixture for 50 cents per 

 thousand. 



TREATMENT OF LEAF-BLIGHT OF THE CHERRY, PLUM, AND QUINCE. 



This disease, which seriously damages the trees both in the nursery and 

 orchard, may be readily held in check by the proper use of either Bor- 

 deaux mixture or the ammoniacal solution. In the orchard and nursery 

 the directions laid down for the treatment of pear scab, cracking, and 

 leaf -blight are applicable here. 



TREATMENT OF BLACK-ROT OF THE CRAPE. 



Method A. — After pruning the vineyard and putting the ground in 

 thorough order spray the vines first, as the buds begin to swell, with 

 Bordeaux mixture. When the leaves are one-third grown make a second 

 application of the same fungicide, following with a third when the vines 

 are in full bloom. After this applications should be continued at intervals of 

 ten or twelve days until the first signs of ripening are noticed. This will 

 usually be three weeks or a month before the grapes are ready to pick. In no 

 cases hould the treatments be continued up to the time of harvest, as this is 

 entirely unnecessary; moreover it is sure to render the fruit unsightly. It 

 is important to bear in mind that in case of dry weather the sprayings 

 should cease. 



Method B. — Following the direction laid down under method A, with 

 the exception that the ammoniacal solution be used instead of Bordeaux 

 mixture. 



Method C. — For the first three sprayings use the Bordeaux mixture, 

 then substitute the ammoniacal solution for the rest of the season. 



The cost of the treatment as laid down in method A need not exceed 2-| 

 cents per vine. Method B will cost 2 cents and method C the same. 



So far as efficacy is concerned there is little choice. All things consid- 

 ered, however, method A will doubtless prove the most satisfactory. 



DOWNY MILDEW OF THE GRAPE. 



When this disease occurs alone ammoniacal solution or modified eau 

 celeste may be used. The first spraying should be made when the fruit is 

 well formed, the others at intervals of ten or twelve days as recommended 

 for black-rot. What is known as brown-rot is caused by the fungus of 

 downy mildew. It is seldom that brown-rot occurs in the berries without 

 the leaves being also affected. In regions where this happens the treat- 

 ment recommended for black-rot should be followed. 



In some sections eau celeste has been more effective against these diseases 

 than any of the other fungicides. This is notably the case in northern 



53 



