ANNUAL REPNORT, 192i9 369 



respect it stands in sharp contrast to the Baldwin, Wealthy, and many 

 other varieties. In most years a light set of Mcintosh is not serious, 

 but in years when the set is naturally rather light, it results in serious 

 limitation of the crop. The problem is a complicated one and it is 

 planned to undertake some co-operative tests with various growers in 

 these two counties in the season of 1930. It is believed that in this way 

 information can be assembled that will help point the way to improved 

 practices that may lessen the danger of light crops in years when the 

 variety fails to set well. 



A Study of the Storage of Mcintosh Under Various Conditions^ (O. C. 



Roberts in co-operation with C, I. Gunness of the Agricultural Engineering 

 Department). The purpose of this study is to determine the relationship 

 between temperature and the satisfactory storage of Mcintosh apples. 

 In conducting this experiment the apples were picked at various stages 

 of maturity and placed in storage rooms with the temperatures at 45', 

 40", 32°, and air-cooled storage re&pectively. As a result of this ex- 

 periment it is hoped that the maximuin temperature at which Mcintosh 

 ijiay be held satisfactorily will be determined. 



Cross-Pollination and Sterility Studies with Certain Apple Varieties- 



(F. C. Sears, O. C. Roberts and others). Work on the cross-pollination 

 of apple varieties was continued this year along similar lines as reported 

 previously. Mcintosh, Cortland and Northern Spy were used as the 

 pistillate varieties. The pollen varieties included the Mcintosh, Delicious 

 Wealthy, Early Mcintosh, Cortland, and Macoun. The last three, rep- 

 resentative of Mcintosh seedlings, were used especially on Mcintosh. 

 The results of this season's work showed Early Mcintosh and Macoun as 

 being of doubtful value as pollinizers for Mcintosh, while Cortland was 

 more satisfactory than the other two. However, the performance of 

 Cortland was not as good as the previous year. 



The effectiveness of the use of bouquets of suitable varieties on the 

 set of Mcintosh was studied. Two Mcintosh trees were covered with 

 tobacco cloth tents to exclude the possibility of natural pollination. A 

 hive of bees was placed under each tree. Then a bucket containing a 

 bouquet of Delicious, Wealthy, and Ben Davis flowers was placed in one 

 of the trees, while in the other tree no pollen varieties were provided. 

 The tree in which the bouquet was placed set approximately five times as 

 many apples as the tree without the bouquet. 



Studies of the Arsenical Residue on Apples. (O. C. Roberts cooperating 

 with the Department of Entomology, and the Boston Federal Food, 

 Drug, and Insecticide Administration). A study of the arsenical residue 

 on apples has been continued this year as formerly with a few slight 

 modifications. Dusts have been used in the later applications to deter- 

 mine if the use of such materials would control the pests and at the same 

 time avoid an excessive deposit of arsenical residue. This appears to be 

 a promising procedure. 



