750 EXPERIMENT STATIOISr RECORD. [Vol. 36 



fungus attacking severely tomato stems and finally the whole plant showed no 

 external differences from P. infestans on potato, but it gave only a slight degree 

 of Infection on potato plants, P. infestans from potato produced no infection on 

 tomato, the form appropriate to which is thought to be a physiological differen- 

 tiated strain of P. infestans. 



Spraying and dusting tomatoes, F. D. Fkomme and H. E. Thomas {Virginia 

 Sta. Bui. 21S (1916), pp. 3-U, figs. S ) .—Continuing previous work (E. S. R., 

 25, p. 548), the results are given of a comparative study of the efficiency of 

 different spray materials and especially of some fungicides applied in the dust 

 form for the control of the leaf spot (Septoria lycopersici) and the late blight 

 (Phytophthora infestans) of tomatoes. The fungicides used were 4:5:50 

 Bordeaux mixture, superfine sulphur to which arsenate of lead was added, 

 and two proprietary fungicides. 



The results obtained show that none of the fungicides gave satisfactory con- 

 trol of the Septoria leaf spot, only about 15 per cent increase in uninfected 

 leaves being noticed for the sprayed plants over tlie checks infected with the 

 fungus. For the late blight and fruit rot, both the liquid and dust applications 

 proved effective for controlling the diseases. Sulphur applied in dry form was 

 the least effective of all the materials used. No foliage or fruit injury was pro- 

 duced by any of the applications. 



Dusting and spraying nursery stock, V, B. Stewart {New York Corfiell 

 Sta. Bui. 385 {1911), pp. S35S61, figs. 9). — Preliminary investigations having 

 given very successful results for the control of various leaf diseases of nursery 

 stock by dusting (E. S. R., 34, p. 747), the author conducted further trials in 

 1916 on a more extensive scale, in which a dust mixture composed of 90 parts 

 of finely ground sulphur and 10 parts of powdered arsenate of lead was em- 

 ployed in an attempt to control the leaf blotch of horse chestnut, leaf spots 

 of currant, plum, cherry, and quince, apple scab, and mildew of rose. 



The results obtained show that, if properly applied, dust sprays will control 

 these diseases in the nursery. The dusting method is considered slightly more 

 expensive, but the applications of the dust mixture can be made in a much 

 shorter time and more thoroughly than can spraying mixtures applied with the 

 usual machines employed by nurserymen. 



A black rot of apples, G. T. Spinks {Univ. Bristol, Ann. Rpt. Agr. and Hort. 

 Research Sta., 1915, pp. 94--96). — In cases of rot showing different colors ap- 

 parently corresponding purely to differences in variety of the apples affected 

 with Monilia fructigena, it is suggested that the color relation depends upon 

 the tannin content or upon the mechanical texture of the apple, but further 

 investigations on this point are in progress. 



A spot disease of apples, B. T. P. Bakkek {Univ. Bristol, Ami. Rpt. Agr. and 

 Hort. Research Sta., 1914, PP- 97-99).— A brief description is given of a spot 

 disease noted in the winters of 1913 and 1914 as prevalent on certain varieties 

 of apples grown at the institute. It is said to resemble in some ways Jonathan 

 spot and bitter pit of apples in the United States. Microscopic examination 

 shows fungus hyphee which kill neighboring cells but do not penetrate deeply. 

 The identity of the causal organism has not been determined. There appears 

 to be some penetration of the cuticle by the fungus hyphse, especially at weak 

 spots. Internal conditions do not appear favorable to the continued develop- 

 ment of the fungus. 



Fungus and other diseases of stone fmiits, G. P. Darnell-Smith and E. 

 MacKinnon {Agr. Gaz. N. S. Wales, 26 {1915), Nos. 7, pp. 589-598, i)ls. 8; 9, 

 pp. 749-753, figs. 4)- — Notes are given on peach leaf curl {Exoascus defor- 

 mans), brown rot {Monilia fructigena, the conidial stage, Sclerotinia fructi- 

 gena, the ascigerous stage, being unknown in Australia), rush {Puccinia 



