200 



GRASSES OP IOWA. 



of the grasses "when grown in moist, 

 shady places, and becoming rank, 

 suffer from this disease From this 

 it would seem that proper drainage 

 would alleviate the trouble. In Eng- 

 land wheat is commonly affected and 

 greatly injured. In moist and shady 

 places in this country it is affected. 

 Eriksson reports the fungus severe 

 Fig. 90A-a, mycelium and erect on wheat at Stockholm, Sweden. Bar- 



conldlophores; ^, c, conldla. . ^ t «. t -rx 



ley and oats are also affected. Von 

 Thumen* states 1hat the fuugus is abundant on Loliumperenne 

 and Dactylis glomerata. The writer has observed it abundantly 

 on several species of Poa, especially Poa ivolfii, near Golden, 

 Colorado. 



Fig. 91. Powdery mildew of grass (Erysip^te gramini^}, 4, Oldlum stage and myce- 

 lium m; B, perltheclum with appendages and mycelium m; C, perltheclum with ascl 

 and ascospores. (Frank.) 



*Bekampfung d. Pllzkrankhelten. 39. 



