PREVENTIVE AND REMEDIAL MEASURES. 49 



Epicoccum. — An undetermined species of this fjenus was obtained 

 in three different cultures made from diseased cranberry vines from 

 01ymi)ia,.Wash. Whether this was the cause of the diseased condi- 

 tion of the vine is not known. 



Diplod'ui. — Dead cranberry vines collected at Wareham, ^Mass., 

 and near Belleplain, X. J., bear a Diplodia not yet satisfactorily 

 identified. The spores are brown, miiseptate. and measure 14 to 18 

 by 8 /u,. 



Chaetomium. — One or two species of this crenus have occurred on 

 leaves kept in a moist chamber and also in cultures made from cran- 

 berry stems and berries. In some cases they may have been due to 

 contamination and in any event are probably not of patholoiiical 

 importance. 



Oofipora. — A funo-us apparently belon<iin<:- to this fjenus has 

 occurred on leaves kept in a moist chamber. 



Macrosporhrm. — An undetermined species of this orenus has also 

 been found in cultures and on leaves kept in a moist chamber. 



PREVENTIVE AND REMEDIAL MEASURES. 

 REGULATION OF TIIK WATKK Sll'lM.V. 



Careful field studies have indicated beyond doubt that the physio- 

 logical condition of the plants, as well as their environment, has much 

 to do with their susceptibility to disease; therefore, anything which 

 promotes the production of vigorous and hardy plants serves as a 

 means of preventing the diseases to a certain extent. It is difficult, or 

 impossible, on account of the very complex factors involved in the 

 conditions of soil, moisture, and the plants themselves, to tell which 

 are of most importance in their relation to the occurrence of dis- 

 eases. Certain cranberry bogs, or portions of bogs, frequently show 

 much more loss from diseases than others. From the experience of 

 various growers, as well as from our own observations, it appears 

 that the control of the water supply is a very important factor. 

 The quantity of water necessary to keep the plants in the most 

 vigorous condition depends largely upon the nature of the soil and 

 subsoil, as well as the contour and natural drainage conditions of 

 the land. The supply of water should be constant and capable of 

 complete control, so as to avoid any great fluctuations during the 

 growing season. In order to accomplish this, the water supply 

 should be obtained from a reservoir rather than directly from a 

 running stream. Some very successful growers find that keeping 

 the water at such a level in the ditches that the surface of the bog 



110 



