22,6 Lee: A Disease of Orange Fruits 613 



In the fifth experiment, with similar methods, leaves of Unshiu 

 orange, sour orange, and pummelo were inoculated. The young 

 leaves of the Unshiu orange showed positive results and fell to 

 the ground; on placing in a moist chamber they developed 

 Gloeosporium acervuli. The leaves of the sour orange and pum- 

 melo remained negative as did also uninoculated leaves of the 

 Unshiu orange. 



These experiments, although apparently on a small scale, 

 would indicate that under unusual weather conditions Gloeospo- 

 rium foliicolum can attack normal leaves of the Unshiu orange, 

 but that the fungus is but slightly pathogenic, if at all, to other 

 Citrus species. The conclusions are also in agreement with 

 those of the present paper pointing to the host restrictions of 

 this fungus to Citrus nobilis and the validity of Nishida's Gloeo- 

 sporium foliicolum. 



Hemmi in his conclusions is apparently of much the same 

 opinion in regard to the pathogenicity of this fungus on foliage 

 as are investigators in California in regard to the pathogenicity 

 of Colletotrichum gloeosporioides ; that is, that unusual climatic 

 conditions must be favorable to the fungus for it to become 

 pathogenic to the foliage. In fruit inoculations we have found 

 that such unusual conditions do favor pathogenicity but are not 

 essential. 



The Japanese disease on Unshiu oranges is quite possibly iden- 

 tical with the disease of emperor mandarin oranges described 

 from Australia. Although the lesions on Unshiu oranges are 

 slightly larger than are the lesions shown in the photographs by 

 Darnell-Smith and Mackinnon(3) on mandarin oran ^ in AuS " 

 tralia, such a slight difference could easily be explained ^r 

 differences in host reactions. The cross ^^^^^^ 

 reported here cannot be considered as more than P^™^ 1 

 they warrant the consideration of Nishida 'sGloe ospon^ foln- 

 colum as distinct from Gloeosporium Umemcolum Clause and 

 Colletotrichum gloeosporioides ^J£^^t£ 

 plant quarantine work also it seems justifiable -to reg 

 disease of mandarin and Unshiu oranges as distinct father 

 kinds of anthracnose and wither tip on Crtrus hosts . ^ 

 nose of mandarin oranges does not yet ^ -JJjgSJJ 

 nor has it been reported from America It i espe *»" ^ impor 

 tant to the Philippines, where .mandarin oi.nge ar ^ the pnn 

 cipal commercial citrus crop, that this disease be exciua 



