40 



C1IMA.TB AUD OTHER FACTORS IN RELATION TO THE DISEA.f?B 



Clinate has a very marked effect upon tlie amo-Ltnt of ergot 

 infection. In dry seasons there is usually very little ergot infection, 

 hut during wet seasons, especially when there is considerahle sunshine 

 during June, it develops abundantly. Warm and sunny seasons are very 

 favorable for ergot infection in the northern part of Erjrope, according 

 to Miiller (185). Ravn (208), viho studied the relation of weather to the 

 degree of infection of various fungi, writes the following for ergot. "For 

 C . purpur ea the temperature condition does not seem to play any role. On 

 the other hand, there exists a close relation between the degree of ergot 

 infection and amount of sun during June, With the exception of the year 

 1894 the rye remained free from ergot in years with a dry June," Rev, 

 Canon Du Port (58) reports a considerable quantity of ergot among the 

 marshland wheats in the year 1879, in which the suirmer was abnormally wet 

 and stmless. Rostrup (216) states that in 1893, because of the dry weather 

 that lasted during the time of blossoming, there was only a very small 

 degree of infection, while the T/et -season in 1894 favored the development of 

 C., t)urpurea so that it occurred very abundantly. In dry and warm air and 

 soil the flowering takes place very rapidly (274) often wholly within the 

 blade (ttiis is true primarily for barley), fhe possibility of infection 

 under such conditions, therefore is very sirall. On the other hand, sudden 

 heat on moist soil causes rapid heading and the coming out of heads long 

 before the flowering. It also causes a wide opening of the glumes. Cool 

 weather prolongs the flowering outside of the blade and so favors infection. 

 Anything tliat prolongs the duration of the flowering period and the time 

 that the glumes remain open also favors ergot infection. For this reason 

 ergot is found more commonly on isolated plants, on those in poorly over- 



