14 LIME-SULPHUK PKEPAKATIONS FOR APPLE DISEASES. 



lime-sulpliur treatment for scab and leaf-spot could be followed by 

 applications of Bordeaux mixture for bitter-rot. 



The self-boiled lime-sulphur is entirely harmless to apple foliage 

 and apparently has a stimulating effect, but it is not as effective 

 against scab as the boiled wash. Our experiments show that it will 

 rontrol mild cases of scab and will entirely prevent leaf -spot, "fruit- 

 spot," and the sooty fungus, but in sections where scab is a serious 

 disease this wash would probably be inefficient. In the Shenandoah 

 Valley of Virgiriia, where scab rarely occurs except in a mild form, 

 and under similar conditions elsewhere the self-boiled lime-sulphur 

 would perhaps be preferable to either the boiled wash or Bordeaux 

 mixture. 



According to the information at hand arsenate of lead is unques- 

 tionably the poison to use with the lime-sulpliur mixtures. Instead 

 of increasing the caustic properties of the mixture, as at first feared, 

 it apparently has the opposite effect to some extent and does not 

 lose any of its insecticidal value by reason of the combination. 



In all the experiments the combination of Paris green and the 

 lime-sulphur solution proved to be quite injurious to apple foliage, 

 and in the Arkansas work the combination of arsenite of lime and 

 lime-sulphur was exceedingl}^ injurious. 



According to the results obtained in the Arkansas experiment, 

 three applications of the commercial solution at a strength of 1 

 gallon to 30 gallons may be made without material injury to apple 

 foliage, but after the fourth application the injurious effect becomes 

 serious, and after the fifth the injury is almost disastrous to both 

 fruit and foliage. It appears, therefore, that the injury is cumula- 

 tive and that it is unsafe to make more than three applications, or 

 four if one is made before the trees bloom. 



SUGGESTIONS FOR TREATMENT. 



It is at present more difhcult to make satisfactory recommenda- 

 tions for spraying apple orchards than it has been for years. Until 

 recently Bordeaux mixture was preeminently the best known fungi- 

 cide for use on the apple, and it was comparatively easy to outline 

 a course of orchard spraying for si given locality, but the advent of 

 new fungicides which, though insufficiently tested, give promise of 

 doing the good work of Bordeaux mixture without its harmful effects, 

 makes the problem more difficult until further experiments shall 

 have shown the exact value of these new preparations. The writer 

 is of the opinion, however, that the information at hand is sufficient 

 to warrant making substitutions for Bordeaux mixture under certain 

 conditions, thus avoiding as much as possible the very undesirable 

 fruit russeting and foliage injury produced by this fungicide. The 

 following tentative outlines for the treatment of diseases of different 

 varieties of apples are suggested: 



[Cir. 54 J 



