748 EXPERIMENT STATION RECORD. 



al this station for several years (E. S. R., 17. p. 466). In the fall of 1913 the 

 author began a study to determine the identity of the organism, means of infec- 

 tion and spread of the disease, its course of development, and the possibility 

 of control. 



The cause of the wilt has been determined to be a species of Lasiodiplodia, 

 to which the name L. triflorw n. sp. has been given. The fungus infests prin- 

 cipally the conducting tissue and the medullary rays of the wood, causing gum 

 formation. The sudden wilting is considered due to a loss of water supply 

 througli the deposits of gum in the conducting elements of the wood. The 

 fungiis, it is said, can not enter through the unbroken bark, but readily enters 

 through wounds, and a large proportion of the infections occur through wounds 

 caused by peach borers. 



For the prevention of this trouble, the author rtx;ommends the cleaning out 

 of channels made by peach borers and removing, if necessary, the surrounding 

 infected tissue, after which the surface is sterilized with corrosive sublimate and 

 covei'ed with gi-afting wax to prevent infection. Bacterial cankers and other 

 wounds should be treated in the same manner. 



[Control of plant diseases and insect enemies], G. Lustner {Ber. K. 

 Lchrannt. ^Vcin, Obst it. Clartenbau Gcisenheim, J91S, pp. 91-100). — A brief dis- 

 cussion is given of tests made with several commercial preparations offered for 

 use against Peronospora and Oidium on grapevines and also against injurious 

 insects. 



Control of grape diseases, M. Lindneb (Ztschr. Obst u. Uartenbau, 40 U91Jf), 

 No. 7, pp. 101-10 Jf, figs. 4; abs. in Mycol. Ccntbl., 5 (1915), Xo. 6. p. 29?).— Direc- 

 tions are given for the employment of Bordeaux and Burgundy mixtures 

 against Pcromjspora (VUmmopara) viticola, and of sublimed or powdered sul- 

 phur against Ohiiuin tiickcri. 



The copper content of fungicidal sprays {Rev. Mt., JfZ (1915), Xo. 1092. pp. 

 469. JflO). — The copper content of Bortleaux and of Burgundy mixtures in 

 common practice is said to have decreased from a concentration of about 8 

 per cent in the early stages of its employment to about 2 iier cent at the pres- 

 ent time. It is thought that the latter concentration should be employed, per- 

 haps twice, about the time when the blooms are open, but that 1.5. 1, or even 

 0.5 per cent may be sufficient under ordinary conditions at other times. 



[Fung'icide injury and fungus control], Fischer (Ber. K. Lehratist. Wein, 

 Obst It. Gartoibdit Gcisenheim. 19t.i, pp. 13-18). — This report deals witli injury 

 to grape leaves and shoots by the use of Bordeaux mixture, and with exi>eri- 

 ments testing the etHciency of three proprietary preparations designed to con- 

 trol Peronospora and Oidium, and of a fourth preparation claimed by a vine 

 grower to give satisfactory I'esults against the.se fungi. 



[The use of fungicides against downy mildew], E. Rabat6 (Jour. Agr. 

 Prat., n. ser., 2S (1915), Xos. 45, pp. 378, 379; 46, pp. 392, 393; 47, pp. 407, 4O8).— 

 This is a discussion of factors to be considered in connection with the control 

 of downy mildew of grape, including the weather and similar conditions (tem- 

 perature, humidity, precipitation, drainage, etc.), resistant varieties, develop- 

 mental stages of the host and parasite, the time and number of fungicidal ap- 

 plications as related to weather and growth, and the forms, compositions, and 

 adaptations of the fungicides recommended. 



Treatment of grape downy mildew as related to the period of blooming 

 (Itev. Tit., 42 (1915), Xo. 1091, pp. 447, 448).— The period during which mildew 

 attack is most to be dreaded is said to be that during which the flowers are 

 newly opened and their tissues are moist and tender. The great losses suffered 

 in 1013 in portions of Algeria were due to an outbreak during this ivriod of 

 .susceptibility. 



