DISEASES OF CULTIVATED PLANTS 495 



some cases where the fruit is in an advanced stage of the disease, 

 the presence of this fungus is indicated by the occurrence of ir- 

 regular black blotches just beneath the skin of the diseased portion. 

 The amount of injury from the rot is apparently not so great as that 

 from the soald. 



Cranberry Anthracnose. Cranberry anthracnose seems to cause 

 less damage in New Jersey than either of the other diseases just de- 

 scribed, but it appears to be more common in Massachusetts and 

 other New England cranberry meadows. It is caused by a species of 

 Glceosporium, which closely resembles the species so injurious to 

 the apple and other fruits. The effect of the fungus upon the fruit 

 is very similar to that of the scald and rot, and can be distinguished 

 from them with certainty only by careful examination or cultures 

 made from the tissues of the diseased berries. All these diseases 

 attack not only the fruit but the leaves. They rarely produce their 

 spores on the leaves until they have fallen or the plant has been en- 

 tirely killed by the fungi or by some other cause. 



Only preventive measures are available at present in combating 

 these diseases. After the parasites have once entered the tissues of 

 the plant they are practically beyond the reach of remedies. 

 Hence, efforts must be devoted to protecting the plants and keeping 

 them in the maximum condition of health and vigor, as in this con- 

 dition they are most capable of resisting disease. 



It has been frequently noticed that the plants on certain cran- 

 berry meadows and portions of meadows suffer much more from rot 

 and scald than others. This is no doubt due in great part, in many 

 cases at least, to the soil and water conditions under which the plants 

 are growing. From personal observations and the experiences of 

 growers it is the opinion of the writer that in the majority of cases 

 the control of the water supply is the most important single factor. 



Just what the best quantity of water is and the best way in 

 which to distribute it can only be determined by study and ex- 

 periment in each case, and will depend largely upon the nature of 

 the soil and subsoil and the nature, contour, and drainage of the 

 land. In general, it may be said that the water supply should be 

 from a reservoir, if possible, and so controlled as to avoid any great 

 fluctuations in the quantity supplied to the plants during the grow- 

 ing season. The cranberry is by nature a water-loving plant, and 

 seems to suffer more frequently from a lack of water than from an 

 excess. 



Another preventive measure of importance is the destruction of 

 all dead vines and leaves. Frequently small areas of vines die, ap- 

 parently from the attacks of the cranberry fungi. All such vines 

 should be pulled or cut and collected early in the spring, at least 

 within two weeks after the water has been drawn from the bog, and 

 burned. Vines which have been cut in raking bogs to prepare them 

 for scooping should also be treated in the same manner. Such vines 

 if not destroyed invariably produce the spores of the cranberry 

 fungi in great quantities and a fertile source of infection for the 

 young leaves and fruit. Little is to be feared from the rotten berries 



