ANNUAL REPORT, 1942 53 



applications (four daj's after the initial applications) increased effectiveness and, 

 in these cases, drop-control was substantial!}' equal to that obtained with sprays. 

 Applications followed in a few hours by rain were less effective. This was also 

 true in the case of a spray which failed to dry before the onset of rain. In one 

 instance, a second application four days after the first not only increased effective- ■ 

 ness but prolonged the duration of effect. 



From these tests, it is evident that spra>' applications were, in general, more 

 effective than dusts although the differences were not so significant but what they 

 may be easih' overcome when dust applications become more perfected. For 

 best control of drop in Massachusetts orchards it may be necessary to increase 

 concentrations somewhat. 



Beach Plum Culture. (J. S. Bailey.) To gain a preliminary basis for pro- 

 cedure and to become more familiar with this fruit and its possibilities, a fertilizer 

 experiment was started at East Sandwich in cooperation with Mr. William Foster 

 and Dr. C. E. Cross. 



A spraying experiment was also conducted consistent with the spray program 

 outlined by Mr. Bertram Tomlinson in Special Cicrular No. 46. This program 

 gave ver\- poor control of plum gouger, the worst insect pest of the beach plum, 

 but eliminated completely a gall maker which was present in great numbers on 

 the leaves of unsprayed bushes adjacent to the sprayed plot. 



Plum Pockets is one of the worst diseases of the beach plum. Plenty of in- 

 fected fruits were found on older bushes surrounding the sprayed plot, but none 

 on the sprayed plot. Brown Rot, another serious disease of the beach plum, 

 and blights were fairly well controlled. 



In cooperation with Dr. H. J. Franklin and Dr. C. E. Cross, a planting of 

 improved selections was made at the Cranberry Station at East Wareham. 

 These selections were supplied by Mr. J. M. Batchelor, plant explorer of the Soil 

 Conservation Service, and are considered, by him, to be the best beach plums to 

 be found anywhere along the east coast. 



Other phases of the work are reported by the Departments of Botany and 

 Horticultural Manufactures. 



Ethylene Dichloride Emulsion. (J. S. Bailey.) Experiments to test ethylene 

 dichloride emulsion for the control of peach tree borers were started in the fall of 

 1940 and continued through 1941 and 1942. Three cases of injury to trees were 

 observed, all of which resulted from over-dosage or faulty application. No 

 injury has been observed where applications were properly made. 



Applications made September, October 1, and October 15, 1941, were very 

 effective in controlling peach tree borers. Those made November 1 and Novem- 

 ber 15, 1941, were not so effective. 



The Use of Peat in Planting Apple Trees. (L. Southwick.) In the 1940 Annual 

 Report, a progress report was made on this experiment which began in the spring 

 of 1939. It was reported at that time that, after two growing seasons, there was 

 no significant difference in growth between the check and the treated trees. After 

 two more years of growth, with scanty fertilization, the same conclusion holds. 



Killing Woody Weed Plants. (J. S. Bailey and L. Southwick.) Ammonium 

 sulfamate at three-fourth pound per gallon of water was very effective in killing 

 chokecherries. The black cherry is much more resistant. Sprays of this material 

 were used at several concentrations and the speed of killing of the leaves was pro- 

 portional to the concentration. It is too early to determine the effectiveness of 

 the various concentrations in destroying the whole plant. 



On July 29, 1942, poison ivy in an apple orchard was thoroughly sprayed with 



