310 PATHOLOGY [Box. Absts., Vol. VIII, 



aration of 16 insecticides and fungicides, 7 commonlj- used fungicides, and 6 less commonly 

 used ones. Lists of manufacturers and dealers in spray machines and spray materials are 

 included. — Henry Dorsey. 



2123. Cheyney, E. G. Preliminary investigation of Ribes as a controlling factor in the 

 spread of white pine blister rust. Science 52 : 342-345. 1920. — The control of white pine blister 

 rust, or rather the protection of white pme, depends on a definite knowledge of the habits 

 of species of Ribes, especially of the wild plants. Projects were therefore planned to cover 

 the following points: (1) To study the sprouting of different species of Ribes eradicated in 

 different months and under different moisturfe conditions; (2) to study the cost and effective- 

 ness of eradication in different months; (3) to determine the number of years eradication 

 will have to be practiced; (4) to study the reproduction of different species of Ribes by seed 

 and layering ; (5) to determine the effect of pruning and cutting off the roots at different depths 

 and at different dates; (6) to determine growth habits of different species. From experi- 

 ments on the areas selected, namely, the Rush Lake region, Minnesota, the following re- 

 sults, though not conclusive, are significant: There was a higher percentage of sprouts from 

 plants eradicated on the moist type of soil than on the dry or swamp types; a larger percent- 

 age of sprouts from plants which were grabbed than from plants which were pulled; tendency 

 to sprout from the root ends seemed muich stronger in plants pulled in May and June than 

 late in summer; plants cut off above the crown almost invariably sprouted in all types and 

 at all seasons, with the exception of the swamp species, R. triste. The number of large plants 

 missed by eradication crews was very small (less than 5 per cent). The number of seedlings 

 left was very much larger, but the leaf surface of these is very small. None of these seed- 

 lings was found to be infected, and is it questionable whether they live over to the second 

 season in large numbers. It has been the practice in the state to pull the plants whenever 

 possible rather than to grub them. Evidence indicates that the reverse practice would be 

 preferable since it seems to be a fact that practically all sprouts come from pieces of crowns 

 and from root ends which are exposed to light. — A. H. Chivers. 



2124. Detwiler, S. B. Safeguarding the white pine crop. Amer. Forestry 27: 7-11. 

 8 fig. 1921. — A resum6 of the conclusions reached by the Sixth Annual International Blister 

 Rust Conference held in Boston, Massachusetts, under the auspices of the American Plant 

 Pest Committee. It was the opinion of the conference that a zone 200-300 yards in width 

 cleared of currant and gooseberry bushes, will insure the commercial growing of white pines 

 under average conditions. In 1920 the cost of control in all states averaged 35 cents per acre 

 as compared with 54 cents in 1919 and 66 cents in 1918. These figures include labor, supervi- 

 sion, and transportation of field men. — Chas. H. Otis. 



2125. Fields, W. S., and John A. Elliott. Making Bordeaux mixture, and some other 

 spraying problems. Arkansas Agric. Exp. Sta. Bull. 172. J2 p., 1 pi. 1920. — The effect of 

 different methods of mixing on the settling and deterioration of Bordeaux mixture is shown 

 in tables and figures. Recommendation is made to dilute the CuS04 solution in the spray 

 tank and to add the milk of lime while agitating the dilute copper solution. No appreciable 

 differences in times of settling of lead arsenate in Bordeaux mixture and in lime-sulphur 

 solution were found with waters of different degrees of hardness. — John A. Elliott. 



2126. Melhus, I. E., and J. C. Oilman. Measuring certain variable factors in potato 

 seed treatment experiments. Phytopath. 11 : 6-17. Fig. 1-5. 1921. — The 3 principal variable 

 factors affecting the value of potato {Solanum tuberosum) seed treatment are: The presence 

 of living pathogenes on the tubers after treatment; the continued antiseptic action of the solu- 

 tion used in the treatment; and the percentage of infection resulting from pathogenes already 

 in the soil. — To study the 1st of these variables, scabby tubers were treated with solutions of 

 formaldehyde and of HgCl2, varying the temperature, the strength of the solution, and the 

 time of exposure. Tissue from scab sori of the treated and the untreated tubers was then 

 plated and the numbers of resulting colonies of the scab organism {Actinomyces scabies) 

 compared. Tubers dipped for 2| minutes in formaldehyde solution 1-120 at a temperature 



