Apple Spraying Experiments in 1916 and 1917. 117 



in these experiments is particularly sensitive to any irritating 

 influence, especially when the apples are small. This has been 

 demonstrated repeatedly for the climatic conditions which pre- 

 vail where the experimental orchard is located. In normal 

 seasons a slight amount of russeting has always appeared on the 

 unsprayed check plot and in the past this has been increased in 

 varying degree by the different spray mixtures used. A com- 

 parison of the results obtained with reference to russeting, 

 during the two seasons present some interesting and unexpected 

 contrasts. 



One of the most prominent facts shown by the tabulated 

 results for 1916 is the relatively high per cent of russeted fruit 

 on each plot, even on the unsprayed check which showed 20.57 

 per cent. This duplicated a condition which prevailed in 1913 

 when over 31 per cent of russeted fruit was obtained on the 

 plot upon which no insecticide or fungicide was applied, and 

 the different sprays produced a corresponding increase in 

 amount. Although this russeting was materially increased by 

 different sprays it is evident that much of it must be attributed 

 to natural causes. The weather conditions of 1913 and 1916 

 were remarkably similar in many ways, and differed from pre- 

 vious seasons in which abnormal fruit russeting did not occur. 

 In 191 3 the first spray application was followed by a month of 

 unseasonably, cold weather, with frosts and cold, north-west 

 winds, associated with much cloudiness and heavy rainfall. In 

 1916 similar conditions prevailed previous to and following the 

 first application. This was also followed in 1916 by heavy rains 

 and continuous cloudy weather in June after the second applica- 

 tion, which was not the case in 191 3. 



The amounts of russeting obtained in 191 7 are contrary, in 

 two respects, to what might be expected as the result of pre- 

 vious experience. While the weather conditions during the 

 early part of the season were similar to those in two years men- 

 tioned above the amount of russeting was relatively slight as 

 compared with that obtained then. What is still more remark- 

 able, it will be seen that on 6 sprayed plots out of 9 there was 

 actually less russeted fruit than on the unsprayed check. Only 

 twice in the 4 preceding seasons, during which an unsprayed 

 check plot had been kept for comparison, did anything like this 

 occur. Each time it was recorded on a single plot and the dif- 



