ANNUAL REPORT, 1939 87 



placed in common storage and the othei in cold storage at 32° F. On November 

 26 samples from these two lots were examined, and the remaining apples left 

 in storage for further examination in January 1940. Results to date show that in 

 both common and cold storage there was an increase in the percentage of apples 

 with medium and heavy amounts of internal cork. The trend seems to be toward 

 an increase in the amount of this trouble in storage rather than a decrease. (See 

 photograph on page 53.) 



Tests of Spray Materials. (O. C. Roberts.) In accordance with a practice 

 which was adopted several years ago, the Departments of Pomology. Entomology, 

 and Botany cooperated in the testing of new spray materials and combinations. 

 Detailed results of the work done this year will be found in the report of the 

 Entomology Department. 



Nutrition of the Highbush Blueberry. Especially in Relation to Soil Reaction. 



(J. S. Bailey.) In the fall of 1938 a number of blueberry plants were removed 

 from the nursery, put in Wagener pots, and placed in a storage cellar where the 

 temperature remained just above freezing. Starting on the fourth of January 

 three plants were moved weekly to a warm greenhouse to see how soon the rest 

 period of blueberries is over. The first plants brought in required nearly four 

 weeks before any activity was indicated by a swelling of the buds, and nearly 

 another four weeks before the plants were in bloom. The plants brought in 

 January 30 required about two weeks to show signs of activity and about three 

 more weeks to come into bloom. The plants brought in the third of March 

 showed signs of activity in 5 days and in 19 more days were in bloom. The 

 last plants brought in were in bloom in 24 days as compared with 54 days for the 

 first ones. 



The plants used in the experiment above were obtained from a nursery where 

 no evidences of iron chlorosis had ever been observed. They were potted in soil 

 from the nursery. In the greenhouse they were given a liberal supply of a com- 

 plete fertilizer, watered plentifully, and the temperature, although fluctuating 

 considerably, averaged rather high. This treatment caused the plants to make a 

 very rapid growth, and several of them developed iron chlorosis. This indicates 

 that some soils might be unsuitable for blueberry growing if the plants are forced 

 to grow too rapidly. 



Blueberry plants were sprayed with 8 percent solutions of each of the following: 

 ferrous sulfate, ferric chloride, soluble ferric phosphate, and ferric sulfate. These 

 sprays all reduced the chlorosis, but all caused more or less leaf burning. 



Blueberry Culture. (J. S. Bailey.) Two plants of the Wareham variety in 

 blueberry plot C appear to have a new blueberry trouble discovered in New 

 Jersey by R. B. Wilcox. The symptoms are a shortening of the internodes and 

 a dwarfing and reddish discoloration of the leaves. The whole plant is dwarfed. 

 The cause of this trouble is unknown. 



Because of the warm, wet fall and the sudden drop in temperature to —4° F. 

 on November 26, 1938, there was considerable winter injury to blueberries. The 

 variety Cabot was injured much worse than any other. Plants of this variety 

 bore an exceedingly light crop in 1939. 



Italian rye grass was tried as a cover crop for blueberries. It was planted 

 about August 15, when the picking season was nearly over, and made a very good 

 growth before cold weather. Since the fall was late and warm, this cover crop 

 probably made a better growth than could be expected in most years. Although 

 it grew very well on soil with a pH of 5.2, it made practically no growth on soil 

 at 4.5. Therefore, it is doubtful if this cover crop will ever prove generally useful 

 for blueberries. 



