L. S. SUBRAMANIAM 



185 



The night after this tree was examined there was heavy rain, and the next 

 morning there was copious growth of the fluffy mycelium on the cut portions 

 of the diseased patches. 



Inoculation Experiments. 



Tobacco. 



The inoculations with the strain isolated from tobacco were successful 

 only under moist conditions. In those cases where the plants were not covered 

 with bell jars they failed. The inoculated portion of the leaf becomes soft 

 and pale in colour within 24 hours, and the chlorophyll is destroyed. The 

 softening gradually extends to the whole leaf, without being limited by the 

 veins, and leads to total dissolution. Infections on the stem and the growing 

 point produce the same results. In Plate III is a plant drawn on the third dav 

 after inoculation. The softening of the infected part is gradually extending 

 to the healthier portions, and the pale-brown, small leaf sticking to the side of 

 the pot shows the wet lot induced as the result of infection from material 

 that ran down off the inoculated leaf. 



The mycelium enters through any part of the epidermis and branches 

 freely in the tissues. The hyphse become constricted before piercing the cell 

 wall. Sporangia are produced only when the infected leaf is floated on water. 

 Irregular swellings on the hyphse are quite common. Oospores are formed 

 both intra- and extra- matrically, the former in larger numbers. Inoculations 

 with this strain on ginger, castor, chilli, papaya, and potato were successful. 



Table I. 



Inoculations ivith strain isolated jrom tobacco. 



