96 AIASS. EXPERIMENT STATION BULLETIN 378 



P, K, Ca, Mg, or B. One of the most striking results was the reaction 

 of the plants to the acetate ion when it was substituted wholly or in 

 part for the sulfate ion. The plants stopped growing and the leaves be- 

 came verjr chlorotic. When the chloride ion was substituted for the 

 acetate ion, the plants partly recovered. 



In cooperation with Dr. Linus H. Jones of the Department of Botany, 

 blueberry plants were grown in the soil temperature tanks at 55°, 60°, 65°, 

 70°, 75°] 80°, 85°, and 90° F. from February 19, 1940, to June 18, 1940. 

 The following results were observed: (1) the plants at the two lower 

 temperatures wilted during the first few days but later recovered; (2) 

 total linear growth and height growth increased as soil temperature in- 

 creased; (3) plants at 70° F. or higher tended to grow tall and upright; 

 those below 70° F., shorter and more spreading. A report of this work 

 will appear in the Proceedings of the American Society for Horticultural 

 Science for 1940. 



Blueberry Culture. (J. S. Bailey.) During the winter of 1939-40 there 

 was considerable winter injury to the tops of blueberry bushes in the 

 Experiment Station plantings. Although all varieties were injured to 

 some extent, Rubel was injured much worse than any of the others. The 

 cause of the trouble was probably a dry fall followed by cold, dry, north 

 and northwest winds during the winter. The month of November was 

 unusually dry. There were three weeks with no rain just before the 

 ground froze. A frozen drj- soil with cold, dr}' winds proved to be a 

 bad combination for blueberries. 



The Italian ryegrass, planted as a cover crop in 1939, was found to 

 be a mixture of Italian and perennial ryegrass. It made a very good 

 growth in most of the field and consequently furnished considerable 

 organic matter, but it was rather difficult to subdue by cultivation the 

 following spring. A further test of cover crops was started in the sum- 

 mer of 1940. Three special lots of seed were received from the Soil 

 Conservation Service; (1) No. 3297 Bromus arvensis, field Brome grass; 

 (2) No. 3197 LoUuni pcrenne, perennial ryegrass; and (3) No. 2965 Phleuvt 

 pratensc, timothy. These were compared with oats and rye. Good stands 

 of oats and rye were obtained, a fair stand of perennial ryegrass, a poor 

 stand of field Brome, and practically no timothy. 



During August, scion wood of the following blueberry selections was 

 received from the U. S. D. A.: DN-76, AW-34, A-91, BM— 22, T-72, R-86, 

 L-25, AR-64, X-58, V-20, U-85, V-25, and AW-35. These were budded 

 into Rubel plants in Row A, Plot C. 



Plants of the newly named Pemberton variety yielded berries of ex- 

 ceptional size, very attractive appearance, and very good flavor. Berry 

 size held up well throughout the season. The Concord variety bore an 

 unusually large crop of large attractive berries this year. 



The blueberry mite was observed for the first time in the College blue- 

 berries. It was not abundant and will probably never be a serious pest. 



Premature Dropping of Mcintosh Apples. (L. South wick.) Work on. 

 this project was reported in Bulletin 372, published in May 1940. The 

 best suggestions that could be made — such as increasing seed number 

 by better pollination, lowering nitrogen in the tree thus decreasing vigor, 

 thinning at the critical time, and spot picking — seemed either impractical 

 or not efifective enough. Unfortunate choice of soils favoring drop 



