486 THE FUNGI WHICH CAUSE PLANT DISEASE 



P. circumscissa Cke. 



Amphigenous; spots orbicular, reddish-brown, at length de- 

 ciduous; pycnidia scattered, minute; conidia elliptic, 8 x 2 /u. 



Spots and shot holes are formed on drupaceous hosts. 



P. prunicola Sacc.^^ 



Spots subcircular, epiphyllous, sordid-brownish or ochraceous, 

 margin subconcolorous; pycnidia scattered, punctiform; conidia 

 ovoid to ellipsoid, 5 x 3 ju. 



It is foimd on Prunus, causing leaf spots in Europe, America 

 and Australia. Scurf is also produced on apple bark. 



P. annenicola Far. is associated with an apricot fruit disease. 



P. grossularise Sacc. grows on Ribes grossularia. 



P. fragaricola D. & R. is widespread in Europe on the strawberry. 



P. vitis Sacc. and P. succedanea (Pass.) All. are fovmd on grape 

 in Europe. 



P. vialse R. & G. also parasitizes the grape. 



P. bizzozeriana Mass. in Hungary produces a grape disease 

 superficially resembling black rot.^' 



P. putrefaciens Sh. occurs on cranberry. 



P. oleae Pet. and P. insulata Mont, cause leaf spots on the olive. 



P. cannabinis Kirch forms spots on hemp leaves; 



P. humuli Sacc. & Speg. on the hop. 



P. bataticola E. & M. Pycnidia scattered, minute, black; spots 

 small rounded, whitish with a purple margin; conidia ellipsoid, 

 5 X 2|t. Ijeaf spots are produced on the sweet potato. 



P. nicotiana E. & E. 



Spots brown, reddish, zonate; pycnidia 200 fi, black; conidia 

 3.5-5 X 1.5 fi. It causes leaf spots of tobacco;" 



P. tabaci Pass, also occurs on Nicotiana. 



P. medicaginis (Fcl.) Sacc. occurs on alfalfa; " 



P. japonica Miy. and P. miuria Miy. parasitize rice. ^' 



P. betae Oud. 



Spots grayish-ochre, large and irregular; pycnidia epiphyllous, 

 minute, densely clustered, brownish, subimmersed; conidia elliptic, 

 5-6x3/1. 



It is mentioned by Stewart " as the cause of leaf spots of beets. 



P. malkoffi Bub. causes cotton leaf spots in Bulgaria. 



P. coffeicola Del. and P. comoensis Del. are on coffee; 



