248 EXPEEIMENT STATION RECORD. 



phate neutralized with lime ; copper sulphate, alum, and Hme ; and iron sulphate 

 neutralized with lime, these fungicides being tested for the control of downy 

 mildew of grapes. 



Groups of vines in the vineyard were sprayed under similar conditions, 4 

 applications being given them, and the effect of the treatment was determined 

 by a committee of inspection. The amounts of copper per unit of leaf surface 

 after the different sprayings up to the beginning of October are reported. 



In every case more copper was present where the vines had been sprayed 

 with a 0.5 per cent solution of copper sulphate neutralized with lime than on any 

 of the other lots. Iron sulphate was found to be without appreciable effect in 

 checking the downy mildew. The addition of iron sulphate to the copper solu- 

 tion diminished the efficiency of the Bordeaux mixture, and the solution to 

 which, alum was added was not as valuable as that in which copper sulphate 

 and lime alone were used. 



American gooseberry mildew (Dept. Agr. and Tech. Instr. Ireland Jour., 6 

 (1906), No. .3. PI). hh'y-'iT'^ P^- 1, t^OS- 2).— An account is given of the goose- 

 l)erry mildew (i^plurrotlicca mors-uvce), which is reported as occurring on red 

 currants in Kilkenny County, Ireland, and a warning is given regarding its 

 possible spread. For its prevention the author recommends spraying with a 

 solution of 2 oz. of potassium sulphid in .3 gal. of water. 



A disease of cottonwood due to Elfvingia megaloma, F. D. Heald {Ne- 

 hraska Sta. Rpt. 1905, pp. 92-100, pis. .'/). — The author reports having observed 

 specimens of living cottonwood in which the entire heart and sapwood were 

 permeated by the mycelium of the fungus Elfvingia megaloma. which produced 

 a gradual dissolution or decomposition of the wood cells and rendered the wood 

 soft and punky in some instances and very brittle in others. 



A brief historical statement is given regarding the distribution of this fungus, 

 the symptoms produced, the anatomy of the host plant, etc., and suggestions 

 are given for its control, which consist in the removal of the diseased trees, 

 destruction of the sporophores, etc. 



Peridermium cerebrum and Cronartium quercuum, C. L. Shear (Jour. 

 Mycol., 12 {1906), No. 83, pp. 89-92). — The common occurrence of Peridermium 

 cerehrum on trunks of ordinary pine about Washington and also the abundance 

 of Cronartium quercuum on oaks in the same vicinity led the author to an inves- 

 tigation to determine the possible connection between the two forms. 



A number of inoculation experiments were undertaken, and the large number 

 of sori occurring on most of the artificially inoculated leaves as compared with 

 the very small number found on the surrounding ones, taken in connection with 

 their much earlier appearance, seems to indicate a genetic relation between the 

 two forms. While the matter can not be regarded as settled, the evidence at 

 hand seems to indicate the connection between the species of Peridermium and 

 the uredo and teleutospore stages which are found on various species of oaks. 



A list of species of pine and oak upon which the two forms are found is 

 appended. 



The adherence of copper fungicides, G. Gastine (Bui. Mens. Off. Renseig. 

 Agr. [Paris], 5 {1906), No. 5, pp. 595-603). — After giving a summary of the 

 investigations of Girard (E. S. R., 3, p. 734) and Guillon and Gouirand (E. S. R., 

 10, p. G51), the author describes his investigations relative to the adhesiveness 

 of various copper fungicides. 



The coefficients of adhesiveness were determined in a manner somewhat differ- 

 ent from that usually employed. The fungicide was thoroughly distributed over 

 grape leaves and glass plates, and after drying, the leaves and plates were 

 washed and the amount of copper removed determined. The proportion between 



