Diseases of plants. 265 



On the prevention of leaf blight and leaf spot of celery, W. C. 



Sturgis {Connecticut State Sta. Rpt. 1897, pp. 167-171).— Notes are 

 given on leaf blight and leaf spot of celery caused by Cercospora apii 

 and Septoria petroselini apii. In the Annual Report of the station for 

 1892 (E. S. R., 4, p. 929) the beneficial effect of sulphur for the preven- 

 tion of this disease was pointed out, but the investigations of the 

 Rhode island Station ' and recent investigations by the author indicate 

 that methods of cultivation exert a very considerable influence on the 

 disease, the level culture seeming to make the plants more liable to 

 infection than the old method of trench culture. The author agrees 

 with the conclusions of the Rhode Island Station, and states that the 

 objections to the level culture may be at least partially removed by 

 mulching heavily between the rows of celery. 



Experiments are reported with fungicides in which Bordeaux mix- 

 ture, potassium sulphid, aminoniacal solution of copper carbonate, and 

 sulphur were tested for the prevention of these diseases. It appeared 

 that sulphur applied as a dry powder was superior to any of the other 

 fungicides. Its effect in checking the spread of the blight in the storage 

 nouse has not been determined. 



Plum leaf spot, S. A. Beach (New York State Sta, Rpt. 1896, pp. 

 384-401, pis. 5). — The experiments here reported are in continuation of 

 those given in Bulletin 98 of the station (E. S. R., 8, p. 139), attempts 

 being made to control the plum leaf spot by spraying with fungicides. 

 As a result of this year's investigations the author recommends spray- 

 ing trees three times with Bordeaux mixture, the first application being 

 made about May 25, or about 10 days after the blossoms have fallen, 

 thf. second about 3 weeks later, and the third about 4 weeks after the 

 second. 



Prevention of fungus diseases in cherry orchards, S. A. Beach 

 (Neic Yorl State Sta. Rpt, 1896, pp. 402-407, pi I).— A report is given 

 of experiments conducted for the prevention of leaf spot and the fruit 

 rot of cherries, which are in continuation of those reported in Bulletin 

 98 of the station (E. S. R., 8, p. 139). In these experiments eau celeste 

 soap mixture was compared with Bordeaux mixture. In 1895, while the 

 diseases were prevented to some extent by the use of fungicides, the 

 foliage was seriously injured, the eau celeste being most injurious. In 

 the experiments in 1896 no injury resulted to the foliage sprayed with 

 Bordeaux mixture, even when the trees were thoroughly drenched with 

 the solution. The results ot the two years' work did not give conclu- 

 sive evidence as to the best lines of treatment of leaf spot on cherry 

 trees, consequently no definite treatment is recommended. 



A steam sterilizer for soils, W. E. Britton (Connecticut State 

 Sta Rpt. 1897, pp. 310-312, pi. 1).— The author figures and describes an 

 apparatus designed for the sterilization of soil by steam, the object 

 being to rid the soil of fungi, fungus spores, nematodes, etc. It was 



1 Rhode Island Sta, Bui. 44 (E. S. R., 9, p. 146). 



