60 



S. E. A. McCallan 



was then ready to be filtered at the same time as those described above. 

 It constituted the "new spore filtrate." The second spore filtrate was 

 prepared in order that possible changes occurring in the old spore filtrate 

 during the period of standing might be checked. 



The solutions after filtering were thus from (i) old spore filtrate, (n) 

 new spore filtrate, (in) distilled water on fungicide, and (iv) old spore 

 filtrate on fungicide. To test these solutions for toxicity, spore-germina- 

 tion tests were made with conidia of Sclerotinia americana. However, in 

 order to have comparative tests — that is, to balance the possible staling 

 effects of the spore filtrates — equal volumes of the spore filtrates were 

 added to equal volumes of solution in. This necessitated adding an 

 equal volume of distilled water to solution iv, so that the respective 

 dilutions would be approximately equal. 



The final solutions in which the spore-germination tests were then 

 made, consisted of (1) control, distilled water, (2) old spore filtrate, (3) 

 new spore filtrate, (4) solution in plus old spore filtrate, (5) solution in 

 plus new spore filtrate, and (6) solution iv plus distilled water. 



The germination tests were made in the usual manner. In general, 

 nos. 1, 2, and 3 were carried in duplicate, 4 and 5 in triplicate, and 6 in 

 quadruplicate, moist-chamber tests. In this manner six separate experi- 

 ments were made with bordeaux membranes and five with copper-lime 

 dust. The results appear, respectively, in tables 11 and 12. 



TABLE 11. Solvent Action on Bordeaux Membranes of Filtrates from Suspensions 

 of Germinating Spores: Percentage Germination of Sclerotinia americana 

 Conidia in the Filtrates 



