, orchard spraying exp^rimejnts. 79 



Summary. 



Spray injury inflicted by properly prepared bordeaux mixture 

 on fruit and foliage is primarily due to part of the materials 

 composing it, and cannot be avoided by any known means when 

 weather conditions following the spraying are favorable for in- 

 jury production. 



The lime-sulphur sprays in the course of many experiments 

 have been found in the majority of cases to be satisfactory sub- 

 stitutes for bordeaux mixture in controlling fungous diseases 

 in orchards. 



Some injury to foliage has been incurred with the use of lime- 

 sulphur sprays. Part of such injury has been due to the use 

 of too concentrated solutions or to leaf injuries caused by in- 

 sects and fungi before the spray was applied. In practically all 

 cases where proper dilutions were used leaf injury on apple 

 trees was so slight that it could be entirely neglected. 



Results of many experiments show absence or reduction of 

 fruit russeting with the use of lime-sulphur. 



The experiments at this station point to the following con- 

 clusions : 



The commercial lime-sulphur sprays were satisfactory as 

 fungicides and were superior to bordeaux mixture in their ef- 

 fect on foliage and fruit. 



The home boiled concentrate was also satisfactory. The in- 

 tensified self-boiled lime-sulphur mixture was less effective and 

 less adhesive than any of the sprays used. 



Lead arsenate was entirely effective as an insecticide when 

 combined with the sulphur sprays. 



Foliage injury occurred on all sprayed plots; it was more 

 severe where bordeaux mixture was used. Leaf injury on the 

 lime-sulphur plots was small in amount and not lasting in its 

 effects. 



Injury to fruit was of two kinds. One was very evidently 

 due to the arsenical used with the sulphur spray. The other 

 form was similar to bordeaux injury, but less severe. 



Unsprayed fruit suffered severe russeting and malformation, 

 due probably to weather conditions. 



Comparison of injured fruit from sprayed and unsprayed 

 trees showed a greater degree of injury to the russeted surfaces 



