36 t)'i t»j-Ji!i I« >v". Vi n?) m "-^ äi n m w -^ 



On the genus lüisariitui a considerable amount of such work lias been done. 



Fusaria, as a rule, seem to require a high temperature for their most 

 virulcnl attack. 



Jones (190.S) sa}s that the damping off <if coniferous sccdings was 

 facilitaled b)' a high temjierature. 



Wollenwibc r (1913) sa)s that the wilt diseases, caused by Fusarium, 

 occiu- most se\'erel\' in warmer climates, 



\\'i)lf (1910) says that the wilt diseases of pansj', caused by Fusai'ium 

 Vio/ac, are found onl}- in Jul)', and then only when the beds in which the 

 plants were growing has been hiax ily covered with fresh horse manure, both 

 ol wliieh facts suggest a dependence of the fungus on high temperature. 



1 lumphre\- (1914) sa>s that Fusarium orthoceras and Fusaritmi oxys- 

 poiiiin cause the tomato blight when the temperature is high. The optimum 

 temperature of the fimgi is al)out 30°C. 



(iilman (KjiT)), who studied the cabbage yellow and the relation of 

 temjieraturi to its occurrence, observed that a high temperature (as 25°C) 

 was fa\drabk: to the mycelial growth of Fusarium couglutiiians, and the 

 germination of the conidia occurred within onl)' three hours at 33°C, and 

 cabbage set.-dlings were attacked most severl)' at 2S^C. to 30^C., but in low 

 temperature (as lO' to 12°C.) the conidia C(juld not germinate. 



Tisdale (iQij), who studied the relation of temperature to the growth 

 and infecting power of Fusarium lini, reported that for the gro\vth of this 

 fungus the minimum temperature is lO' to 11 C, the optimum is 26° to 

 28^C., and the maximum is 35^ to 36'C., on the potato agar medium ; and 

 the critical temperatiu'c for the infection of this fungus is 14° to l6°C., 



E-XPERIMEXT I. 



Effect of temperature on the nnxelial growth of the fungiis. 



1 used the synthetic solution of following formula for the cultural medium : 

 Ammonium nitrate (NHiNO;,) i.oo gram 



Potassium biphosphate (KH.,rOj) 050 „ 



Magnesium sulphate cr\'stal (MgSOj) 0.25 



Cane Sugar (Q.^L^O,,) 20.00 ,. 



