i8o Bulletin 395 



During the summer of 191 1 Dr. P. J. Anderson conducted spraying 

 experiments in raspberry fields at Brant, New York. This work was 

 continued by J. H. Muncie during the summer of 191 2, and by the writer 

 during the seasons of 19 13 and 191 4, after which the experiments were 

 brought to a close. A large number of spray materials, alone and in 

 combination, were used. The results of the experiments were recorded 

 for the most part on the basis of percentages of infected canes. This 

 in itself is unsatisfactory, as it does not show the severity of infection 

 and gives no indication as to the effect of the spray on the yield of fruit, 

 which is really the ultimate aim. Thus very little data were obtained 

 indicating that spraying was effective. 



A few well-checked experiments, however, are worthy of recording. 

 In two plats, each containing approximately one hundred and thirty-two 

 bushes, three applications of bordeaux mixture, 4-4-50, reduced the 

 number of diseased canes to 23 per cent and 16 per cent, respectively, 

 while the untreated bushes showed infection to the extent of 77 per cent 

 and 71 per cent, respectively. The first application was made when 

 the young shoots were from eight to ten inches high, and the following 

 applications were made at interv^als of two weeks. These experiments 

 were repeated for several seasons, with similar results. After the third 

 application the ripening of the fruit prevented further treatments, although 

 the lateral branches were not fully mature and occasionally during this 

 period infections occurred. These infections were observed only in a few 

 cases, however, and then they were not severe. Spraying after fruiting 

 time is useless for several reasons. Infections seldom take place late 

 in the season, and furthermore the new growth that develops after August 

 is removed when the plants are pruned the following spring. 



Besides bordeaux mixture various other chemicals were used. Lime- 

 sulfur, self-boiled lime-sulfur, and iron sulfate were tested, but none of 

 these gave satisfactory results. The adhesive quality of the iron sulfate 

 in combination with the other spray materials also was investigated, but 

 sufficient benefits were not observed to warrant recommending its use. 

 Lime-sulfur, i gallon to 40 gallons of water, precipitated with iron sulfate, 

 7 1 pounds to 100 gallons, gave a reduction in the percentage of infected 

 canes. The spraying, however, dwarfed the plants considerably, causing 

 them to bear small fruit with an insipid flavor. Bordeaux, on the other 

 hand, caused only a slight burning of the tender leaves. 



The application of a spray solution when the plants are in a donnant 

 condition, as suggested by several investigators, was tested thoroughly 

 during four seasons. Various strengths of iron sulfate, the greatest 

 being 2 pounds of the material to i gallon of water, copi^er sulfate 4 pounds 

 to 50 gallons of water, and lime-sulfur i to 8, proved to be of no benefit. 



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