Fungi, Bacteria und Pathologie. 277 



described before. The oospores claimed to have been found by 

 Rostowzew have not been tound. It has been iotind that thtre is no 

 evidence that the fungus lives over the winter on dead vines and leaves 

 but tvvo theories are advanced to account for this step in its life history. 

 One is, that plants in greenhouses harbor the fungus and the otlier is, 

 that it advances with the season froni the south where it survives the 

 winter season on out of door plants. The hosts vary in their suscepti- 

 biiity to the injuries of the fungus The squash and watermelon have 

 been reported as badly injured but the cucumber and muskmelon have 

 ordinarily suffered most 1 he financial loss has been great but no esti- 

 tnate is made as to its proportions. When the disease is severe it is 

 concluded that spraying niuskmelons is useless. The cucumber^ how- 

 ever, is benefited by spraying. A list of ö6 citations of papers treating 

 of this disease follows the paper, basides several plates illustrating the 

 disease and the germination of the spores and zoospores. 



The downy mildew of potatoes caused by Phytophtlwra infestans 

 (Mont) Hetz, is taken up quite thoroughly. It is concluded that the 

 disease is carried over winter by the infected tubers. Early varieties of 

 potatoes suffer less from this disease. The character of the season is 

 the dominating factor in the progress of this trouble. Selection of unaffec- 

 ted seed, thorough cultivation, and ridging to cover the tubers with a 

 deeper layer of earth to prevent infection are recommended. 



Perley Spaulding, 



Green, W. J. and F. H. Ballon, Winter-killing of peach 



trees. (Ohio Agricl. Expt. Stat. Bull. LVII. 1904. p. 115 



— 132.) 



This bulletin discusses the extensive winter killing of peach trees 

 in the Lake Erie fruit belt of Ohio. The cause of this v/inter killing 

 determined to be the low vitality of the trees, generally due to the 

 attacks ofSan Jose scale, leaf curl, lack of food^ and imperfect drai- 

 nage. In exceptional cases very rapid growth and poorly matured wood 

 resulting from over fertilization or very rieh soll were the reasons for 

 the dying of trees No trees were injured under the following circum- 

 stances: thorough and continuous spraying for fungi and scale, where 

 there was even a very slight mulch under the trees, where trees were 

 Standing in sod, where the bases were protected by a few shovels of 

 dirt, peat, or manure. Perley Spaulding. 



Lawrence, W. H., Blackspot Canker. (Washington Agri- 

 cultiiral Experiment Station Bulletin. LXVI. p. 1 — 35. 

 12 pls. 67 figs. 1904.) 



This bulletin gives the results of a careful study of the disease of 

 the apple known locally as the Black-spot Canker, and the fungus 

 which causes it, Gloeosporium malicorticis Cord. Similar canker diseases 

 are reported on the alder, cherry, pear, plum, prune and willow. None 

 of these have yet been proven to be caused by the fungus uTiich pro- 

 duces the apple canker. 



The apple canker attacks all varieties of apple trees in Washing- 

 ton, Oregon, Idaho, and British Columbia often causing great 

 injury to the trees. Some varieties are much more susceptible to attack 

 than others. Northern Spy, Waxen, and Ben Davis are comparatively 

 free from disease. 



The Blackspot fungus like the bitter rot fungus causes a disease 

 of both the tree and fruit, but unlike it the canker stage does a far 

 greater amount of injury. From differences in characters, Gloeosporium 

 malicorticis is held to be specifically distinct from Glomerella riifoma- 

 ciilans Spaulding and von Schenck. No comparative study of the two 

 fungi is reported. Remedies of a preventitive nature are given at the 

 close of the bulletin. Hedgcock. 



