3S6 Report of the Horticultural Department op the 



tinguish it. On another part of the tree some open blossoms 

 which had not been sprayed were tagged for comparison with the 

 sprayed blossoms. 



A Jefferies apple tree which showed its first bloom May 13, 

 also had a part of its blossoms sprayed May 14. They were 

 marked after the same plan which was- followed with the Hurl- 

 but and unsprayed blossoms were likewise tagged for comparison. 



Later observations showed that out of 42 sprayed Hurlbut 

 blossoms which were known to have been hit by the spray 36, or 

 86 per ct., failed to set fruit, while out of 31 corresponding 

 blossoms which were not sprayed only 5, or but 16 per ct. failed to 

 set fruit. Out of 11 Jefferies blossoms known to have been hit 

 by the spray 8, or 73 per ct. set no fruit while out of 10 corre- 

 sponding unsprayed blossoms only 3, or 30 per ct., failed to set 

 fruit. None of the blossoms which were seen with spray mix- 

 ture on the stigmatic surface of the pistils set fruit on either 

 tree. 



The Baldwin and R. I. Greening trees which were used in this 

 test were sprayed a week later, on May 21, using the same kind 

 of spray mixture as before. It was difficult at this time to find 

 branches of the tree which were, proi)erly speaking, in full bloom 

 because in so many cases the center flower of the cluster had 

 already gone out of bloom. The center blossom of the cluster 

 opens first and naturally may be expected to drop its petals before 

 the other flowers of the cluster do. Some branches were finally 

 found on the northeast side of the tree on which most of the 

 clusters were s±ill, strictly speaking, in full bloom, although, in 

 the blossoms on two of the trees as the sequel shows, the pollen 

 tubes had doubtless in the majority of cases already entered the 

 style and passed beyond the reach of the poisonous influence of 

 the spray mixture. After they had been sprayed ®ome of the 

 blossoms were examined and tagged in the way already described 

 for the Hurlbut blossoms. Corresponding unsprayed blossoms 

 were likewise labeled. Later observations showed that none of 

 of the blossoms which had the stigmatic surfaces plainly covered 

 by the spray mixture set fruit. Out of 45 R. I. Greening blossoms 



