68 PROTECTION OF PLANTS— 1924-25 



on plants that were flowering, then those with half grown pods and lastly seed- 

 lings. The lesions were generally noticeable in from five to six days after ino- 

 culation as brown flecks that slowly developed and took on the characteristic 

 color for the part infected. It was found impossible to distinguish between the 

 ear y stages of this disease and anthracnose. Special attempts were made to 

 get infection upon the full grown pods. They were placed in a spore suspension 

 for from 48 to 70 hours and this failed. The epidermis was rubbed to remove 

 the trichomes but without result. An attempt to get infection with spores in a 

 dilute agar gave very confusing results as the checks also gave a browning of 

 the epidermis like a lesion. 



A brief study of the method of infection indicated that infection takes 

 place through the more unprotected parts of the plant and in one instance what 

 looked like infection through a stomate was observed. The tendency of the 

 disease to develop around tender parts and around the old wounds from the 

 dropping of the cotyledons would make it seem that it needed a break in the 

 epidermis to establish itself readily. 



The organism was reisolated repeatedly from the lesion, the affected tissue 

 being first externally sterilized. 



Summary and conclusions. 



I. An organism isolated from a bean pod secured from Annapolis county, 

 Nova Scotia, apparently infected with C. lindemuthianum is temporarily consi- 

 dered as being Phyllosticta phaseolina Sacc. and distinct from the conidial stage 



• of Diaporthe phaseolarum (C. & E.) Sacc. commonly considered as Phoma sub- 

 circtna a and which primarily causes a pod spot of lima beans. 



II. The organism seems to agree very close'y with the descr'pt'on given 

 by Smith of Phy losticta phaseolina but further work is necessaey actual y to 

 dete-mine by comparative cultures whether the present isolation is essentially 

 P. 'phaseolina. 



III. The organism has already l}een reported by Dearness from Canada as 

 occurring on Phaseolus paj-ennis. 



IV. It has not been possible to determine its economic importance and the 

 disease has been studied only from articificial inoculations on Phaseolus vulgaris 

 ■n the greenhouse. Under such conditions it is important because of the 

 •njury to blossom. 



Dept. of Botany, 



Macdonald College, 

 P. Q. Can. 



Note. — Since this paper was submitted for publication Dr L.L. Harter, to whom a culture 

 was sent, writes as of June 15, 192.5. "It resembles very closely the organism which I have isolated 

 and studied frequpnty from material collected from various parts of the United States." 



