342 EXPERIMENT STATION RECORD. 



same fungus. It is believed questionable whether the Botryosphseria which 

 he has studied is really the same as the one common on a large number of 

 woody plants throughout the country. In conclusion he states that as the 

 Botryosphjneria found on cotton bolls in the South is not connected with a 

 Diplodia, it would api)ear to be specifically distinct from the common form. 



Some field experiments with potato rot, J. F. Monroe {Ami. Rpt. Quebec Soc. 

 Protec. Plants [eic], 3 (1910-11), pp. Jfl, ^2). — A brief report is given of 

 experiments with 29 varieties of potatoes for the prevention of rot by means 

 of the application of Bordeaux mixture. The plants were sprayed 5 times 

 throughout the season, and an arsenical was added to the first application. 



The season, it is said, was eminently favorable to the development of the rot, 

 and tabulated data showing the yields indicate that with many varieties a 

 large percentage was diseased, even where the plants had been sprayed. A few 

 varieties showed remarkable disease resistance. 



Experiments with potato scab, C. von Wahl {Ber. Grossh. Bad. Landw. 

 Vers. Anst. Augustenb., 1910, pp. 58-60). — Experiments were carried on for 2 

 years. 



Corrosive sublimate solution of 0.05 per cent and Bordeaux mixture of 2 per 

 cent, both applied to the seed potatoes for li hours, gave excellent and about 

 equal results in the prevention of scab, as was also the case with Bordeaux 

 mixture of 2 per cent applied to 2 lots for 3 and 14 hours, respectively, and 

 with 2 lots treated with 4 kg. per are (356 lb. per acre) of sulphur mixed 

 with the soil, one lot having been also thoroughly rubbed with sulphur before 

 planting. A peat mold dressing of 35 cm. depth appeared to give some protec- 

 tion against the development of scab, while a sand dressing of the same depth 

 afforded none. On both the plats treated with soil dressing the next year's 

 crops were found to be healthy. 



Experiments with the application of lime as a remedy against finger-and- 

 toe disease, F. K. Ravn {Tidsskr. Landhr. PlanteavL. 18 {1911), No. 3, pp. 

 357-392). — The experiments showed that Dales Hybrid turnip is relatively re- 

 sistant, but not immune to the disease. Applications of lime were only suc- 

 cessful when sufiicieut amounts were supplied (24,000 lbs. calcium carbonate 

 per tondeland, or 1.3S acres, on the soil experimented with) to make the re- 

 action of the soil strongly alkaline. No material difference in the effect of the 

 lime was observed whether this was harrowed or plowed into the ground, nor 

 did air-slaked quicklime produce appreciably better results than corresponding 

 quantities of calcium carbonate. 



Lampsana vulgaris as a host plant of lettuce Peronospora, E. Noffray 

 {Jour. Agr. Prat., n. ser., 22 {1911), No. 51, pp. 781-783).— The author calls 

 attention to the fact that the principal host plant for the lettuce mildew {Per- 

 onospora gangJiformis) is the uncultivated plant L. vulgaris. For the preven- 

 tion of attack in lettuce beds, the author recommends the destruction of all 

 weeds of this species, together with those of the common senecio, as it also is a 

 host of the parasite. 



Experiments on spore germination and infection in certain species of 

 Oomycetes, I. E. Melhus {Wisconsin fita. Research Bill. 15, pp. 25-91, pis. 7). — 

 An outline is given of the studies carried on with Cystopus candidus, a com- 

 mon parasite of the radish. Investigations were made of the conditions influ- 

 encing the germination of the conidia, the infection of the host plant, and the 

 occurrence of so-called physiological species of Cystopus on various cruciferous 

 plants. 



It was found that the conidia germinated best in water and usually at a 

 low temperature, the optimum being about 10° C, with a range from nearly 

 zero to 25° C. Environmental characters, season, and host vitality seemed to 



