Bui. 227, U. S. Dept. of Agriculture 
7 40 
Plate IV. 
r r;Y 
Toxicity Studies: Petri-Dish Cultures of Fomes annosus and Fomes pinicola.— ill. 
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; 45, on 
0.6 per cent. Figs. 46 to 4S.— F. annosus on different concentrations of wood tar (hardwooO) 
after about 3 weeks: 46, On 0.1 per cent; 47, on 0.5 per cent; 48, check. Figs. 49 to 51.- Jf. 
annosus on different concentrations of copperized oil: 49, On O.o per cent after about 3^e_eks. 
50, on 1.75 per cent after about 3 weeks; 51, on 36 per cent after about o^weeks x l £- oZ -— 
F. pinicola on 50 per cent concentration of None-Such Special after about 3' -weeks. ±igs. ci 
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. 
