December, 1908.] 



559 



Plant Sanitation. 



" If the dead tree is not immediately 

 destroyed by fire the disease rapidly 

 spreads to the neighbouring trees, and 

 finally throughout the whole plant- 

 ation." 



A bud rot in Travancore is described 

 in a letter in Ferguson's " All about 

 the Coconut," and in the Indian Forester 

 for 1894. It is a " decay of the tender, un- 

 expanded leaf shoot. At first the lower 

 end of the shoot grows discoloured, 

 and, in a few days, general putrefaction 

 of this and more or less of the 

 cabbage ensues ; the shoot drops, and, in 

 some cases, falls to the ground ; the tree 

 decays soon after and we are left lookers- 

 on and losers. ... It is only the 

 most vigorous trees that are, as a rule, 

 affected." The natives ascribe it to 

 falling stars. 



A bud rot of the Palmyra and other 

 palms near the mouth of the Godaveri 

 River is said to have been seen as long 

 ago as 1894, but was not reported until 

 1904, and not on coconut until 1905. E. J. 

 Butler published a careful study of this 

 disease in 1907, at which time it infested 

 a circle of about 14 miles radius. 



The first symptom is a discolouration 

 of a recently-expanded leaf, which then 

 turns white and withers ; other leaves 

 follow ; the nuts fall prematurely and no 

 more are formed. 



The leaf sheaths of all diseased trees 

 are marked by irregular, sunken spots 

 in greater or less number. In the earlier 

 stages . . . the spots are white ; 

 later on they become brown. They are 

 always sunken and usually have some- 

 what raised edges. They begin in the 

 outer sheaths and may be traced in 



through succeeding ones toward the 

 heart of the bud. As the inner layers 

 are softer, the inside patches are often 

 larger than those outside, and may even 

 give rise to new patches which extend 

 out again to the outside sheath. . . . 

 The earlier patches are dry and either 

 free from any appearance of a parasite 

 on the surface or covered with a white 

 mycelial felt. Very soon a wet rot 

 follows, which extends with great; 

 rapidity in the delicate central tissues 

 and converts the whole heart into a 

 foul-smelling mass of putrefaction, in 

 which everything is involved, and the 

 original agent is lost sight of, 



It is only in the early stages before the 

 wet rot starts that the true cause can be 

 made out. This is a fungus of the genus 

 Pythium ... In quite young spots 

 the mycelium is found only within the 

 leaf tissues where its threads extend 

 between the cells, sending little branches 

 or haustoria in to them. . . Later on 

 it comes out on the surface, formiug 

 often a dense white felt of filaments 

 bearing sporangia. There is no positive 

 information as to its dissemination. No 

 remedial measures intended to cure trees 

 already attacked are possible. 



It was first recommended by Butler 

 that all infected trees be burned, and 

 that apparently healthy trees in infected 

 districts be treated with Bordeaux 

 mixture. A considerable force of men 

 has been employed in the immediate 

 restriction of the disease in this locality, 

 and, as a result of experience under the 

 local conditions, the use of fungicides 

 has been given up. The work is now 

 concentrated in the cremation of the 

 sources of infection. — Philippine Agri- 

 cultural Review, Vol. I., No. 5, May, 1908. 



