6 Fig " Canher" caused by Phoma cinerescens Sacc. 



a badly diseased branch, showing numerous threads of spores, was 

 cut through ; immediately afterwards the same knife was used for 

 making an incision in the bark of a branch of a healthy young plant of 

 Ficus religiosa. At the expiration of 10 days the wound showed un- 

 doubted symptoms of disease and at the end of five weeks the white 

 threads of spores were found. This experiment proves that the disease 

 may be imparted to healthy plants by using a knife that had previously 

 been used for pruning diseased plants, and an examination of various 

 diseased plants suggests the idea that this method of spreading the 

 disease is not an unusual one." 



Since the above work was not conducted with a pure culture of 

 the fungus, and especially since we had found associated with the 

 Fig "canker" disease a quite distinct fungus from that described 

 by Mr Massee, it was important to obtain scientific evidence of the 

 parasitism of Phoma cinerescens. 



It was found that pure cultures could be obtained by two methods : 



(1) A portion of a tendril obtained from the canker shown in the 

 illustration (Plate I, fig. 1) was placed in a drop of sterilized distilled 

 water; after dilution a small drop containing conidia was transferred 

 to a tube of melted agar (prepared with an extract of prunes as nutrient) 

 and a "poured plate" made. One such plate produced six sporelings; 

 growth was rather slow and after eleven days the mycelial masses only 

 measured from 4 to 7 mm. in diameter. From each of two of these a 

 tube culture on an agar slant was prepared. In the tube cultures growth 

 continued with more vigour and in seven days each showed a rather 

 dense, flat, hyaline disc of mycelium about 2 cm. in diameter with 

 a raised white ring of aerial hyphae midway between the point of origin 

 and the periphery. Later these slant cultures consisted of a rich 

 growth of dark brown mycelium with a few whitish tufts. 



(2) An alternative method of obtaining cultures of the fungus 

 was also adopted. The canker referred to above was cut across and 

 transverse sections made through the discoloured wood. In this wood 

 the vessels were found to be blocked with hyphae, tyloses and "wound- 

 gum." Two small fragments of such sections made with a sterile 

 razor were each transferred by means of a flamed platinum wire to an 

 agar slant. The resulting growth resembled that obtained under 

 similar conditions with mycelium produced from the poured plate of 

 conidia, the white ring of aerial mycelium at a short distance from the 

 point of inoculation again being a characteristic feature. The inference 

 is that the mycelium in the aft'ected tissues of the xylem is that of the 



