470 Report of the Mycologist of the 



Stuart's* experiments on spore-germination show that it cannot 

 possibly have any value as a preventive of rust. Some germina- 

 tion occurred in a solution twenty-eight times the strength of this 

 formula. 



Copper sulphate: — It has been found that plain copper sulphate 

 solutions of considerable strength may be used on carnations 

 'without injury to the foliage. Mr. C. W. Ward has used as much 

 as three pounds of copper sulphate to a barrel of water without 

 any noticeable injury to the plants. Prof. Taftf found a 1-1000 

 solution of copper sulphate, applied once a week, entirely suc- 

 cessful against carnation rust and recommended this treatment 

 as being the most satisfactory. 



Other fungicides which have occasionally been used and recom- 

 mended are: — Ammooiacal copper carbonate solution, fir-tree oil. 

 Littles' "Antipest," common salt, copper chloride, corrosive sub- 

 limate, sulphate of iron and arsenic. 



Spore-Germination in Fungicides. 



A fungicide protects a plant from the attacks of parasitic fungi 

 by preventing the germination of fungus spores which happen to 

 come in contact with the foliage of the plant. As a guide to the 

 intelligent use of a fungicide against a particular fungus it is, 

 therefore, important to know whether the fungicide is capable 

 of preventing the germination of the fungus spores. Fungicides 

 which prevent the germination of spores of some species of fungi 

 may not be able to prevent the germination of spores of other 

 species of fungi or else stronger solutions will be required. It is 

 nearly always advisable to make laboratory tests of spore-germi- 

 nation in the fungicide to be tested before undertaking spraying 

 experiments. Time is saved by so doing. 



The germination tests of rust spores herein reported were made 

 for the purpose of determining the best fungicide to use against 

 carnation rust. In all cases the spores were germinated in hang- 

 ing di'ops in Van Tieghem cells. In the check cells plain 



♦Stuart,' AVm., Some Studies upon Carnation Rnst.'^Sth Ann. Rept. .Vermont Exp. Sta., 

 1894, p. 116. Also American Fh.rist, Vol. IX., July'36, 1894, p. 1232.' 

 t Taft L. R., Carnation Rust Combated. IFlorists' Exchange, Vol. Vll., p. 123. 



