PYTHIUM 



105 



Bud-rot of palms. During the past few years a peculiar 

 disease attacking palms in the Godavari delta, India, has 

 been investigated by Dr. Butler, Imperial Mycologist, Re- 



FIG. 23. Pythium de baryanum, i, seedlings of cress (Le- 

 pidium sativum] attacked by the fungus ; 2, mycelium bearing 

 conidia at the tips of the branches ; 3, sporangia in different 

 stages, also a free zoospore ; 4, an oosphere with the antheridium 

 or male organ, which has pierced the wall of the oosphere, and 

 inserted a slender tube for the purpose of allowing the contents 

 of the antheridium to mingle with those of the oosphere. After 

 this blending of the contents of the two organs, the oosphere^ 

 becomes surrounded by a thick wall to form the oospore, of 

 sexually produced resting-spore ; 5, a germinating conidium. 

 Fig. i. nat. size ; remainder highly mag. 



search Institute, Pusa. The palmyra palm (Borassus flabel- 

 lifer) suffers most, but the cocoanut palm is also attacked. 

 The symptoms are such that the disease can be recognised 

 fairly easily. The earliest sign is the turning white of one of 

 the leaves recently expanded, towards the centre of the bud ; 

 withering follows. Other leaves are attacked in turn, and 

 finally the whole top withers and falls off. The primary cause 

 of disease is Pythium palmivorum (Butler). Irregular, sunken 

 patches are formed on the leaf-sheaths, particularly in the 



