ANNUAL REPORT, 1932 



21 



epidemic form in September, and destroyed not only tlie last pickings of the early 

 crops hut practically all of the late fields in the eastern half of the State. In 

 addition, it ruined varying portions of the fall crop in many greenhouses in the 

 Boston Market Garden section. The disease did not reach the Connecticut 

 Valley crops until shortly before the fields were abandoned because of freeze injury. 

 The only previously reported occurrence of this disease in Massachusetts was in 

 1905, when the damage was slight. 



THE CRANBERRY STATION 



(East Wareharn, Massachusetts) 



H. J. Franklin in Charge 



Injurious and Beneficial Insects Affecting the Cranberry. (H. J. Frank- 

 lin.) 



Control of the cranberry root grub {Amphicoma vulpina). Some of the cranberry 

 growers now have very efificient rigs for treating this pest with cyanide solution. 

 Three-quarters of an acre a day can be treated with one of them at a cost of not 

 over $55 an acre, with the present wage scale. However, this treatment never 

 kills quite all of the grubs and so probably must be repeated in about ten years. 

 Because of this and the cost of the treatment, it has seemed desirable to develop a 

 control by flooding if possible. In this connection, the season's experience in the 

 flooding of two badly infested bogs seems highly suggestive. On one of these bogs 

 the full winter flood was held till July 4. This very late holding of the winter 

 water failed to reduce the grub infestation noticeably. The winter flood was re- 

 moved from the other bog on April 3, and the bog was reflooded again from May 16 

 to July 9, the water ranging from 6 inches to 2 feet deep over the sand surface. 

 The temperature of the water of this reflow was taken in two widely separated 

 locations carefully selected to represent average conditions, at depths of 6 inches 

 and 1 foot, at 7 a. m. and 2 p. m. from May 27 to July 9, inclusive. The following 

 table shows the range of these temperatures. 



Months Highest 



May (S days) Lowest 



Average 



Highest 



June (30 days) Lowest 



Average 



Highest 



July (9 days) Lowest 



Average 



So few of the grubs survived this reflow that they could hardly be found. It 

 seems certain that the grubs were killed by the long reflow following, after a con- 

 siderable period, early removal of the winter flood; but as the results of this treat- 

 ment were so markedly different from those obtained by very late holding of the 

 winter water, it should be tried further. 



It was observed that the false blossom leafhopper iOphiola) hatched in con- 

 siderable numbers on both bogs after the late flooding operations described above. 



Pyrethrum dust. (Dr. E. A. Richmond, employed locally by the Crop Protection 

 Institute, cooperating.) The last annual report of the Cranberry Station con- 



