Bui. 227, U. S. Dept. of Agriculture 



7 40 



Plate IV, 



Toxicity Studies: Petri-Dish Cultures of Fomes annosus and Fomes pinicola.— III. 



Figs 40 to 45 — F. pinicola on different concentrations of wood tar (hardwood) after 2 weeks: 

 40, Check; 41, on 0.2 per cent; 42, on 0.3 per cent ; 43, on 0.4 per cent : 44, on 0.5 per cent; 4o, on 

 6 per cent. Figs. 4(5 to 4s.— F. annosus on different concentrations of wood tar (hardwood) 

 after about 3 weeks: 4G, On 0.1 per cent: 17. on 0.5 per cent; 48, check. Figs. 49 to 51.— i >. 

 annosus on different concentrations of copperized oil: 49. On 0.5 per cent after aDOUt3weefcs. 

 50, on 1.75 per cent after about 3 weeks: 51, on 36 per cent after about. 5] ..weeks, * IG. M.— 

 F. pinicola on 50 per cent concentration of None-Such Special after about .,', weeks. J<IGS. . 

 and 54.— .F. pinicola on different concentrations of zinc chlond (commercial) after 4 weeks. 

 53, On 0.7 per cent; 54, on 0.75 per cent. 



