REPORT OF THE CRANBERRY SUBSTATION. 139 



the cranberry roots extended for some time before the kilhng took place, 

 and the vines were exposed to strong, drj', northerly winds most of the 

 three weeks ending February 5. On some badly injured bogs, areas not 

 picked the fall before showed little harm, and new plantings in which 

 the vines were still in the hills were not hurt, while heavy \'ines near by 

 that had been picked were badly killed. 



From these and other observations the writer ventures to guess that 

 cranberry winterkilling usually is due to a drjdng out of the vines result- 

 ing from a freezing in of the roots that prohibits their taking in moisture 

 to replace that given off by the leaves exposed to strong, dry winds. As 

 the dormant cranberry foliage is hard and tough, it probably parts with 

 its moisture very slowly, even in the most drying weather, and the writer 

 thinks it usuall}^ takes several days of such exposure to kill the vines. 

 The escape from injury of new plantings and unpicked vines may have 

 been due to their being less dry before they were exposed to winterkilling 

 conditions than were the picked vines, their roots not having been dis- 

 turbed. 



The spring and early summer of 1917 were late, cold and wet, and as a 

 result the cranberry crop was very tardy in ripening. There was little or 

 no frost injury in the spring, but on the nights of September 10 and 11 

 hard freezes caught the berries still in a green or slightly colored condi- 

 tion. The minimum bog temperature recorded at the station on the 10th 

 was 24-r F., and on the 11th, 26° F. The first night the wind at the 

 station was from the northeast, with a velocity of 10 miles an hour at 

 8 P.M., and an average of 3f miles from midnight to 6 a.m. This wind 

 was very generally, though, as it proved, unwisely, relied on to prevent a 

 hard frost. Temperatures as low as 18° F. were reported from some bogs, 

 severe injury being common except in Barnstable County and on the 

 Vineyard and Nantucket, all of which escaped with little or no hurt. 

 The night of the 11th, however, bogs in Barnstable County suffered much 

 loss. 



From growers' reports the writer estimated the Cape cranberry loss 

 for both nights to be 60 per cent. Mr. V. A. Sanders, field agent of the 

 Bureau of Crop Estimates, set the loss in Plymouth County at about 

 67 per cent, and in Barnstable County at about 37 per cent. This re- 

 duction, added to that due to the winterkilling and the rather large fruit- 

 worm injury, left the smallest crop picked on the Cape since 1905, only 

 118,574 barrels of berries, exclusive of those marketed locally and those 

 canned and evaporated, being shipped from this section. 



From observations made on Sept. 2, 1916, and on the night of Sept. 

 10, 1917, it is certain that cranberries in the greenish white state that 

 immediately precedes the ripening of the fruit will endure a temperature 

 of 26° F. without hurt, and of 25° F. with little injury, but 24° F. seems 

 to harm such fruit greatly if it continues long. 



The winter of 1917-18 was the most severe in New England of any on 

 record. The ponds and streams were low in the late fall and early winter, 



