L. S. SUBRAMANIAM 183 



There also a Pythiuni was found in, all diseased plants. Slabs cut out ^nth a 

 red hot knife from the interior of steins that were only slightly diseased, and 

 grown under aseptic conditions, gave pure cultures of the Pythium only. He 

 did not carry out inoculation experiments. 



McKae studied th,e field characters of the disease in detail and gives the 

 following account of it : — " The first outward indication of the disease in the 

 growing crop is a general but slight paleness of the leaves of a shoot, then the 

 tips of the leaves turn yellow, and this yellowing gradually spreads along the 

 leaf towards the leaf -sheath, often more rapidly along the margins. Then 

 the leaf-tissue dies and becomes scarious from the tip, the dead area gradually 

 extending towards the leaf-sheath followdng in the wake of the yellowish dis- 

 colouration. The leaves droop and hang dow^n along the stem, till finally the 

 whole shoot becomes dry and withered. Meantime the collar, that part of 

 the aerial stem between the place where it arises from the rhizome and w^here it 

 emerges from the ground, becomes of a pale, translucent brown colour, and, 

 by the time the leaves are w'ell yellow^ed, it is very watery and soft so that the 

 whole shoot can easily be lifted of£, breaking aw^ay at this point though not 

 falling over spontaneously. This soft rot also extends beyond the collar into 

 the rhizome. The rotting is accelerated by the combined action of other 

 fungi and of small eehvorms and the larvse of flies which act as secondary agents. 

 Both the discolouration and softening extend to the whole rhizome, which 

 gradually rots and disintegrates, forming a loose w^atery mass of putrefying 

 tissue enclosed by the tough rind. The vascular strands lie isolated inside. 

 The roots attached to the affected parts also present the same symptoms." 



During the last few years, numerous cases of an obscure disease like the 

 " foot rot " of Citrus trees w^ere observed on papaya trees {Carica Pajjmja) in 

 the vicinity of Pusa. It has also been reported from Kathiawar (Western 

 India), Dacca and Burma. Especially during the rainy season of 1909 the 

 disease was very severe in the kitchen garden of this Institute. 



The first indication of the disease is the whetting of the bark at the region 

 of the collar and softening of the tissues with a copious exudation of 

 latex which turns brown on coagulation. The patch expands gradually on all 

 sides, sometimes to two feet in length from the base upwards. The tissues 

 inside get discoloured and rotten and give rise to a foul-smelling mass wherein 

 maggots breed in large numbers. The decay travels through the bark into 

 the cambium and thence into the wood, causing rot as it progresses. This 

 rotting continues as long as the weather is damp but is checked by dry weather. 

 The outer bark is then thrown off and a patch is formed, exposing the inner tissue 



