182 PATHOLOGY |BoT. Absts., Vol. VII, 



destroy currants and gooseberries within 200 feet of the pines if they are to save the pines. 

 The rust has not been found in Western United States, and the existing quarantines are con- 

 sidered a safeguard. The resolutions adopted urgently recommend that the destruction of 

 the currants and gooseberries in white pine stands be adopted generally in infected regions; 

 that pine and currant growing regions be segregated by law; that the cultivated black cur- 

 rant be outlawed; that state and federal experimental work be continued; that scouting in 

 the western states be continued; and that an accurate census of the white pine in the country 

 be made by the federal government. The experimental and practical control work done on 

 control areas in the various states is summarized by states. No blister rust was found on 

 pines in 1919 outside the New England States, New York, Minnesota, and Wisconsin. — 

 W. H. Rankin. 



1225. Du COMET, V. De la lutte centre le Phytophtora infestans. [Combating Phyto- 

 phtora infestans.] Bull. Soc. Path. Veg. France 7:59-65. 1920.— The principal work car- 

 ried on in different countries in the prevention of late blight of potato is reviewed. In the 

 author's region — Grignon — four applications of Bordeaux mixture are sufficient in the worst 

 seasons, and usually two suffice. — C. L. Shear. 



1226. DuTTON, W. C. Dusting and spraying experiments of 1918 and 1919. Michigan 

 Agric. Exp. Sta. Special Bull. 102. 50 p., 20 fig. 1920.— Comparative dusting and spraying ex- 

 periments with fungicides and insecticides were carried on in 1918 and 1919 in several orchards 

 in various parts of Michigan, the fruits being apple, cherry, plum, peach and currants. A few 

 experiments were also made with potatoes. For apples, the scab was as well, and in some 

 cases better, controlled by the sulphur dust than by the lime-sulphur spray. Dry lime- 

 sulfur dissolved in water and sprayed gave poor control, as did barium tetrasulphide (B. T. S.). 

 The latter caused russeting of the fruit in some varieties. The lime-sulphur sprays injured 

 the leaves a little, while the sulphur dust did no harm. Of the insecticides, lead arsenate 

 gave uniformly good results. Calcium arsenate burned the foliage somewhat and gave only 

 fair control of coddling moth. Magnesium arsenate, on the contrary, was unsatisfactory as a 

 control and caused serious burning. On cherries, dusting with sulphur (90 parts) and lead 

 arsenate (10 parts) did not control, although it delayed for about two weeks the onset of leaf 

 blight {Coccomyces hiemalis). The trees were badly defoliated by the middle of September. 

 The trees sprayed with lime-sulphur (plus arsenate of lead) remained free from the disease 

 until late in September, more than two months after the last spraying, when a small amount 

 of infection occurred. In the same orchard the dusted and check trees showed serious loss 

 from Coniothyrium, which caused cankers at the point of attachment of the fruit pedicel, 

 causing the drying up of the fruit. The sprayed trees did not show this trouble. Other 

 spraying and dusting experiments with cherry and plum were inconclusive because of lack of 

 insect and fungous trouble in the unsprayed plots. For leaf curl {Exoascus deformans) of the 

 peach the 90-10 dust mixture (sulphur and lead arsenate) applied March 7 was practically of 

 no value. The Niagara soluble sulphur was only very slightly better. The dry-lime-sulphur 

 dissolved and applied as a spray showed much better results than the dust treatments, but 

 still did not give good control. Magnesium arsenate as an insecticide caused almost com- 

 plete defoliation of the peach. Currants sprayed with bordeaux mixture remained healthy 

 throughout the season; those dusted and those sprayed with lime-sulphur showed yellowing 

 of the leaves and lost much foliage. Bordeaux mixture controlled the anthracnose (Pseudo- 

 peziza ribis) successfully. The other treatments reduced the anthracnose but did not con- 

 trol it. Of the varieties tested, the untreated bushes showed great variation in suscepti- 

 bility to anthracnose. Prince Albert is very resistant; London Market resistant. Wilder, 

 Perfection, Fay's Prolific, La Versailles, Cherry and Red Cross are susceptible; and Red 

 Dutch is very susceptible. With potatoes, calcium arsenate applied as a dry dust (85 parts 

 with 15 parts of talc as a filler) or sprayed on at the rate of 1^ lbs. in 50 gallons give equally 

 perfect control of the Colorado potato beetle. — E. A. Bessey. 



1227. Evans, N. H. Report on experiments for the control of Apple Scab. Ann. Rept. 

 Dept. Agric. (British Columbia) 14: 25-27. 1920. 



