THE BUD-ROT OF PALMS IN INDIA. 



263 



village such scattered cases continued to recur with the greatest 

 persistence. In two small areas kept under continuous observation 

 which had been cleared of a large number of diseased trees in Nov- 

 ember 1906, five subsequent inspections up to September 1908 

 yielded fresh cases. It was impossible that outwardly diseased 

 trees could have escaped cutting on these occasions, since the plots 

 were close to the road through the village which was frequently 

 traversed by those in charge of the work. Similarly outside infec- 

 tion was scarcely to be thought of, for the whole village, as well as 

 those adjoining, had been very thoroughly and repeatedly worked 

 over, being the head-quarters of the Taluk where the campaign was 

 prosecuted with the greatest energy. Examination of several of 

 these cases showed that the outer leaf-sheaths bore unmistakable 

 evidence of previous infection, the old brown spots on the outer 

 sheaths being split and dried up. The sheaths of at least two years' 

 leaf supply often remain attached to the tree, and there was every 

 reason to suppose that some of the spots seen on this and other occa- 

 sions on the outer sheaths may have been two years old. It is now 

 believed that such old spots may serve for a considerable time to 

 re-start an active phase of the disease. This is probably brought 

 about through the tardy germination of resting spores, which have 

 several times been found in the dried mycelial webs on the surface 

 of old spots. The mycelial growth resulting from the germination 

 of the resting spores is small and soon terminated by the formation 

 of one or two sporangia. The spores from these would settle on 

 the sheaths in contact and might succeed in penetrating them, where- 

 as from their small number and entangled position in tlio old sheaths 

 there would be little likelihood of tlie sporangia being carried to 

 other palms before germination. 



Several cases of arrested penetration have been seen. In one, 

 a previously healthy palm was found with fresh spots on the outei- 

 sheaths on the 6th July. On October 23rd it was cut and spots 

 found extending through 4 sheaths, after which the spread had 

 apparently stopped. In another, some 10 sheaths had been pene- 

 trated but all the spots were old and the innermost appeared to have 



