DISEASES OF PLANTS. 755 



timber in which light or dark violet to dirty red-colored spots and larger areas 

 of grays to grayish browu appear In the wood. This staining, it is claimed, 

 is due to the fungus, Z. resince. The characteristics of the fungus and its 

 synonymy are discussed. 



Blue stain on lumber, Caroline Rumbold (^Science, n. set:, S'f {1911), No. 

 <%"'/, PP- 9-'i-96). — -The results are given of exi)eriments with different chemicals 

 in preventing the blue stains on lumber caused by fungi, especially by certain 

 species of Ceratostomella and Graph) um. 



Sap boards of yellow pine, red gum, green yellow pine, and green red gum^ 

 were dipped in hot and in cold solutions (from 1 to as high as 10 per cent) 

 of sodium carbonate and sodium bicarbonate, after which the boards were 

 inoculated with the spores of C. cchinrUa. 



These tests showed that an 8 per cent solution of sodium carbonate was as 

 effective as an 11 per cent solution of sodium bicarbonate. These strengths 

 prevented blue staining on red gum when the weather was rainy, while in dry 

 wejither a 5 per cent sodium carbonate and a 4 per cent sodium bicarbonate 

 solution kept yellow pine boards unstained. 



Freshly cut red gum and yellow pine sap boards required 8 per cent sodium 

 carbonate and 10 per cent sodium bicarbonate solutions to prevent blue staining 

 when the fungi were growing vigorously. A greater resistance to the alkali 

 in the medium was shown by the si)ores of Ceratostomella than by the mycelium. 



A disease of orchid leaves, F. T. Brooks {Gard. Chron., 3. ser., 50 (1911), 

 No. 1281, p. 27). — Attention is called to a recent outbreak in the orchid house at 

 the Cambridge Botanical Garden of leaf spot {Hypodermkim orchidearum) on 

 the leaves of different kinds of orchids, including species of Thunia and 

 Dendrobium. 



The disease begins at the apex of the leaf and spreads downward, producing 

 a discoloration of the affected areas and finally the death of the leaf. It is 

 checked by sponging the leaves with a dilute solution of potassium per- 

 manganate. 



Extermination of eelworms. .1. Smith (Oard. Chron., 3. sen, 50 {1911), No. 

 1280, p. 7). — It is claimed that by top-dressing the pots containing the infected 

 plants with rape meal the eelworms in the soil are destroyed and the diseased 

 plants benefited. 



The chemistry of lime-sulphur wash, W. B. Burgess (Jour. Southeast, Agr. 

 Col. Wjjc. 1910, No. 19, pp. 61-69). — The author gives the results of investi- 

 gations as to the most satisfactory proportion of lime and sulphur for making 

 the wash, and as to the chemical changes which the mixture undergoes when 

 exiwsed to the air under conditions similar to those which obtain when it is 

 used as a summer spray. No definite conclusions were reached as to the exact 

 proportion between the lime and sulphur but on the whole the most satisfactory 

 ratio seems to be from 150 to 200 lbs. of sulphur to 100 lbs. of lime. 



In testing the behavior of the mixture when exposed to air, the amounts 

 of polysulphid and thiosulphate sulphur and of lime were determined. A given 

 amount of the mixture was then exposed to the air and these constituents 

 again estimated. It was found that the wash as a summer fungicide acts in 2 

 distinct ways, (1) as a contact spray, the polysulphids acting in a way similar 

 to potassium sulphid, and (2) as a protective coating to the leaves, due to the 

 thin layer of finely divided sulphur deposited from the thiosulphates and poly- 

 sulphids by decomposition. 



Some recent experiments with lime-sulphur spray, E. Wallace (Proc. 

 Aincr. Pomol. Soc, 1911, pp. 272-281). — This paper is a summary of con- 

 clusions, the subject matter of which is embodied in 3 New York Cornell Station 

 bulletins, all of which have been previously noted (E. S. B... 25, pp. 47, 48, 49). 



