192 MASS. EXPERIMENT STATION BULLETIN 180. 



The table shows little if any increase in yield from this treatment. The 

 berries of both plots, however, showed a rather remarkable improvement 

 in keeping quality over the fruit of the unsprayed checks, especially when 

 the small number and lateness of the treatments are considered. In both 

 cases the two checks were laid out on opposite sides of the plot. 



While these tests are not enough to prove a fungicidal value for arsenate 

 of lead in the treatment of any cranberry disease, their results are sugges- 

 tive. It should be recalled in this connection that this insecticide is a well- 

 proved treatment for apple scab. Dr. Shear found that most of the rot 

 in Early Black berries produced by the station bog this year was due to 

 anthracnose, a disease caused by a fungus known to science as Glomerella 

 rufomaculans vaccinii Shear. 



To test further the possibility of controlling fungous diseases by putting 

 copper sulfate in the flowage, experimental flooding sections 23 and 27 of 

 the station bog were treated, as in 1915, with this chemical in the June 

 reflow at the rate of 1 part to 50,000 parts of water (1 pound in 6,250 gal- 

 lons). The treatment was applied June 14 after the sections had been 

 completely submerged for twelve hours, and the water was then held 

 thirty hours longer. Even distribution of the chemical was obtained by 

 pulling it around in a sack in the water as it dissolved. The areas thus 

 treated showed no definite advantage either in the quantity or the keeping 

 quality of the fruit, as compared with the untreated flooding sections 

 adjoining them. 



It seemed to be the general opinion among the Cape growers that cran- 

 berries as a rule kept distinctly better than usual this year in spite of the 

 wet weather in the first half of the growing season. 



The hypertrophy of the tender vegetative shoots, frequently called 

 "false blossom" by the growers, and for which Dr. Shear has suggested 

 the name "rose bloom," was unusually abundant on the station bog 

 this season. It has been thought that the moisture conditions attending 

 late holding of the winter-flowage, excessive reflowage, deficient drainage 

 or excessive and continual rainfall greatly favor the development of the 

 fungus (Exobasidium oxycocci Rostr.) which causes this disease. The late 

 holding of the winter-flowage in both 1915 and 1916 in conjunction with the 

 very rainy season may, therefore, partly explain its prevalence on the bog. 



An unusual occurrence with this disease was its attack on the blossoms, 

 its effects hitherto, so far as observed, being confined to the leafy shoots. 

 As estimated from 3 to 4 per cent, of the Howes blossoms on the station 

 bog were conspicuously deformed by the disease between July 20 and 

 August 1, when this effect was most marked. An occasional Early Black 

 flower was also affected. A few of the small berries were somewhat 

 swollen and discolored by the disease, and covered with the spores of the 

 fungus. That this attack on the flowers and small berries probably was 

 due mainly to the prolonged spell of wet weather was shown by the prompt 

 disappearance of the disease on both blossoms and vines when the wet 

 season ended. 



