50 EXPERIMENT STATION RECORD. 



The conditions conducive to serious iiijuiy fioiii root rot are the infection of 

 the seed bed or of the field with the fungus, a lieavy soil rich in humus, ex- 

 cessive fertilization, heavy watering, and lack of ventilation of the seed beds. 



Cucumber and tomato canker, G. Massee {Roy. Bot. (lard. Kciv, JiuL Misc. 

 Inform., HW9, Xo. 7, pi). 2!) J, 2'.>.i, pt. J ; Jour. Bd. Affr. { London], 16 (1900), No. 

 7, PI). ,T7.''-.)iS/). — Attention is called to a disease of melons in the T'nited States 

 recently described as due to MycosphwreVa citruUina (E. S. R., 21, p. 148), 

 and it is stated that specimens of diseased tomato plants as well as cucumber 

 plants have been examined at Kew and found affected by the same fungus. The 

 conidial form of the fungus is apparently responsible for the rapid extension of 

 the disease. It is shown that the si)oros from diseased cucumber plants readily 

 infect young tomato plants, as would the spores from tomato plants infect the 

 vegetable nuu-row plants. 



While dclinite results have not been obtained by Investigations, it is thought 

 that thorough spraying witli Bordeaux mixture would prevent the occurrence 

 of this disease. 



The gummosis of fruit trees, H. Blin (Rev. Hort. [Paris], 81 {1909), No. 5, 

 pp. 115-117). — A description is given of the gummosis of fruit trees, which has 

 proved particularly destructive to peaches, but also attacks apricots, clierries, 

 and plums. This disease has been attributed to various causes, and attention 

 is called to it in the hope that definite investigations will be carried on to de- 

 termine the specific cause as a preliminary to the discovery of methods of con- 

 trol. 



Spraying for apple scab or black spot, C. W. Mally {Agr. Jour. Cape Good 

 Hope, 35 {1909), No. 2, pp. 202-211, figs. Jf). — An account is given of spraying 

 experiments for the control of the apple scab {Fusieladium dendritieum), 

 which has appeared as a destructive parasite in southern Africa. The experi- 

 ments were conducted in an orchard which was kept under good cultivation, 

 over 300 trees being used in the test. Bordeaux mixture of the 6 : 4 : 50 formula 

 was used, and 1 to 3 applications given the trees. 



The control trees were badly attacked by the disease and at least half the 

 fruit dropped and the remaining poi'tion was badly deformed by the scab. The 

 trees receiving one spraying showed about 60 per cent sound fruit, the trees 

 receiving the first and second sprayings, over 90 per cent, and those sprayed 

 three times were practically free from disease. Where the trees were siirayed 

 three times, however, the fungicide caused some injury, which about counter- 

 balanced the extra margin of sound fruit. 



The control of black rot of the grape, C. L. Shear, G. F. Miles, and L. A. 

 Hawkins {U. S. Dcpt. Agr., Bur. Plant Indus. Bui. 155, pp. Jf2, pis. 5, figs. 2). — 

 A report is given of a series of investigations undertaken to demonstrate the 

 efficiency of the best methods practiced and at the same time to improve if pos- 

 sible methods and mixtures for the control of the black rot of the grape, and 

 also to secure additional knowledge regarding the life history and habits of the 

 black rot fungus {Guignardia bidwellii) and other parasitic fungi of the grape. 

 This work was begun in 1006 and has been extended until in 1908 it was car- 

 ried on in Pennsylvania, Michigan, New York, and New Jersey. A considerable 

 number of fungicides were tested, most of them being various copper com- 

 pounds, but comparisons were made with lime-sulphur mixtures. The work at 

 the different stations is described at length. 



A study of the tables presented shows that where different numbers of appli- 

 cations were made, 5 applications at the proper times gave nearly or quite as 

 satisfactory results as 6, 7, or 8. A Bordeaux mixture prepared according to 

 the 4 : 3 : 50 formula was found as effective in preventing black rot as fungi- 



