RESISTANCE TO TEMPERATURES 103 



H. pulcherrimwm, Lentimis lepidens, Schizophyllum commune, 

 and Pleurotus o streams. The third group comprises Phlebia stri- 

 gosazonata, Stereum fuscum, Poly poms hirsutus, Ganoderma luci- 

 dum, Lenzites saepiaria, L. trabea, and Pamis riidis. 



Studies to date on the temperature relations of wood-destroy- 

 ing fungi have involved their Growth on artificial media rather 

 than on wood [Herrick (1939)]. It is conceivable that there may 

 be little, if anv, correlation of growth rates on such different sub- 

 strates. Lindgren (1933) indicated that two reasons may be as- 

 signed for a lack of correlation: (1) the chemical and phvsical 

 differences between nutrient agar and wood; and (2) the time 

 factor, cultivation on agar being confined to periods of short dura- 

 tion and on wood in nature to long periods. These reasons appear 

 to be sufficient to render unreliable anv predictions of the rate of 

 decay of timber on the basis of the rate of growth on agar of the 

 causal fungus. 



RESISTANCE TO LOW TEMPERATURES AND 

 HIGH TEMPERATURES 



Experiments to determine the ability of fungi to survive when 

 subjected to temperatures in excess of those known to inhibit 

 growth and reproduction are meager. The results of these experi- 

 ments, however, show that fungi are much more tolerant of low 

 than of high temperatures. Evidently, as the temperature is 

 elevated above the maximum for growth, desiccation and coagu- 

 lation of proteins occur, and these reactions become the proximate 

 cause of death. At low temperatures, on the other hand, these 

 profound changes in proteins may not be accomplished, and 

 other explanations are needed to account for the death of the 

 fungus. 



Low temperatures. The temperatures employed in ordinary 

 refrigeration and cold storage are^very effective in inhibiting the 

 growth of such fungi as those causing decay of meats, fruits, vege- 

 tables, and other foodstuffs. 



Lauritzen (1929) found that a storage temperature of less than 

 2° C is required to prevent decay of turnips, induced by Rhizoc- 

 tonia solam. At a maintained temperature of 8° to 10° C this 

 fungus caused 62 to 87% decay within a period of 2 years. 



Brooks and Cooley (1917) stored apples inoculated with vari- 

 ous decay-producing fungi at 0° C with the result that the rots 



