EXPERIMENT STATION BULLETINS. 



437 



TABLE 3. — COMMERCIAL GRADES OF GRIMES GOLDEN, 1020. 



The percentages of "total A & B" for the lime-sulphur and sulphur dust 

 plots were exactly the same. The percentage of "ciders" from these plots 

 was considerably lower than the actual percentage of scabby fruits which 

 shows that every apple bearing a scab spot was not graded as a cull. This 

 is accounted for in part by the legal tolerance of imperfect apples allowed by 

 the grading law and is further accounted for by the fact that many of the 

 scab spots were probably not recognized as such when packed. On some of 

 the trees there were many small apples which were graded as culls or ciders 

 because of small size rather than because of scab or worms. 



The difference in the percentages of A's between the lime-sulphur and sul- 

 phur dust plots was undoubtedly due to a larger proportion of small apples 

 in the sulphur-dust plot, which were not affected by the dusting or spraying 

 material used. 



The point of this discussion is this. The fact that a given lot of apples 

 packs out a certain proportion, 90 per cent for example, of A and B grades, 

 does not mean that 90 per cent of the apples were actually free from injury 

 by scab or insects or to express it the other way, the percentage of scabby 

 and wormy fruit as shown by experimental counts should not be interpreted 

 to mean that this percentage of the fruit will be culls when commercially 

 graded. 



Effect on foliage and fruit. There was no definite foliage injury by any of 

 the materials but the foliage of dusted trees was generally brighter and 

 cleaner in appearance than that of the sprayed trees. 



EXPERIMENTS IN 1921. 



Experiments of this nature were conducted in two orchards in 1921, one at 

 Fennville on the farm of Mr. P. H. Broe and one in the Grand Traverse 

 Peninsula on the farm of C. F. and J. W. Stickney. 



EXPERIMENT AT FENNVILLE. 



The six-year-old Jonathan and Wealthy orchard on the P. H. Broe farm at 

 Fennville was used for a comparative test of spraying and dusting. These 

 varieties were planted in alternate rows. The trees bore good crops this 

 year. 



Materials and applications. The materials used and the periods at which 

 they were applied were as follows: 



