746 EXPERIMENT STATION RECORD. [Vol.40 



In the wheat-smut investigations it was found that normal grains from par- 

 tially smutted heads do not transmit the disease. Sprinkling the seed with 

 strong copper sulphate solutions greatly reduced infection from smut in the 

 soil. Early plantings (August) were practically free from smut and give good 

 yields. Smut loss can not be accurately estimated by head count. Replowing, 

 which had been suggested as a means of reducing smut, increased rather than 

 reduced the yield. The use of exhaust fans on thrashing machines, if properly 

 installed, was found to lessen the danger of explosions, to improve the quality 

 of the wheat, and to prevent much of the smut dust from passing out through 

 the stacker. 



Continued studies were made of Rhizoctonia diseases, and it was found that 

 the blight of tomato is caused by Rhizoctonia and that the disease may be 

 transmitted from the potato to the tomato. The treatment of seed-potato 

 tubers with mercuric chlorid, while not increasing the yield of table stock, is 

 recommended for use in the production of extra fancy or seed stock free from 

 sclerotia. Seed selection, it Is claimed, Is more valuable for the prevention of 

 loss from Rhizoctonia than seed treatment. 



In continuation of investigations of fire blight, leaf invasions of Bacillus 

 amylovorus were produced by Inoculation, and twig blight was caused by 

 migration of the organisms downward through the leaf petioles. 



Powdery scab of potatoes is considered comparatively harmless in Wash- 

 ington, and Investigations have Indicated that spindling sprouts of potatoes 

 may result from p< m .]■ conditions of storage. 



Brief notes are given on the Identification of a number of miscellaneous 

 diseases. 



Spraying for fungus diseases: How to prepare Bordeaux, D. McAxPfNI 

 {Fruit World Austral.. 19 (1918), No. 9, pp. '/>. -In addition to giving 



directions tor the preparation of fungicides, the author states that no amount 



of poor or air-slaked lime could produce g l Bordeaux mixture, failures being 



often attributable to the use of such a defective Ingredient A simple copper 

 sulphate solution (2 li'--. copper sulphate to 50 -:!. water) with 4 lbs. soft soap 

 makes a cheap and valuable fungicide for dry districts, but it may scorch the 

 leaves if applied after the buds open. Spraying should commence when the 

 buds are just on the point of bursting. Properly prepared Bordeaux will not 

 injure apples even when in full bloom, and the operation should be deferred 

 until the blooms are at hast partially open. 



Copper stearate. A. H. I.kks (Univ. Bristol, Attn. Rpt. Agr. and Hurt. Research 

 Sta., 1917, pp. 39-42). — I'aratlin emulsion having given satisfactory results as 

 regards the wetting of difficull surfaces (E. S. R., .".7. p. 759), the author tirade 

 an attempt to combine soap with Burgundy mixture (Bordeaux being consid- 

 ered unsuitable for that purpose) made in the ordinary way. 



It was found that interaction occurred, resulting in a curdy precipitate and 

 rendering the soap inactive. The addition of ammonia to copper sulphate gave 

 a stable mixture, but required a considerable amount of ammonia, which grad- 

 ually evaporated, leaving the copper sulphate to react with the soap. The sur- 

 face was thus finally covered with a soap which is called copper stearate. less 

 ammonia was required if a certain amount of caustic soda was added at the 

 same time as the carbonate and soap, but the resulting mixture caused defolia- 

 tion and was otherwise somewhat unsatisfactory. Later if was found that if 

 the mixing took place in the reverse way, copper sulphate solution being added 

 to soap solution, a more satisfactory result could be obtained so long as the soap 

 was in excess and the solutions sufficiently dilute. The mixture when made as 

 sumes a characteristic opaque light blue color, which proved to be due to an 



