OCCURRENCE OF THE DISEASE ON OTHER PALMS. 155 



and the course of the decay seemed to have been alonp; the line of the bases of the leaf 

 sheaths which form the protective covering of the tender growint; ])oint of the stem.' 



Coleman made infection experiments ])oth in tlio nuts and at the 

 growing point of the tree, using Phytophtliora for that i)urposc. Tlie 

 inocuhitions of the nuts took very easily, as did that of the growing 

 point. In regard to the latter he says: 



An examination made two weeks after inoculation showed that the fungus had 

 grown right through the several underlying leaf sheaths and had attacked the 

 growing point. ^ 



In view of these inoculations by Mr. Coleman there can be little 

 doubt that he has found the cause of the disease. The resemblance 

 between this betel-nut-palm disease and the coconut-palm disease is, 

 however, most strikmg, infection occurring as blackening of the 

 tissues either in the flower stalks or in the crown of leaves, or in both; 

 subsequent infection of the growing pomt; soft rot and death of the 

 tree; in the case of the betel-nut palm or areca palm, Phytophtliora 

 believed to cause the disease, although numerous bacteria are present 

 in the diseased growing point; in the case of the coconut palm, 

 Bacillus coli proved to be the cause of the disease, although Diplodia 

 is usually abundant on diseased nuts and the upper part of the 

 middle leaves. 



In some ways the disease of the ro3^al pahn of Cuba resembles more 

 closely the areca-palm disease than it does that of the coconut palm. 

 It is not at all improbable that some fungus may be found to occasion 

 this. 



The palmyra palm of India has a disease similar in general aspect 

 to that of the areca palm, but it is said to be due to a species of 

 Pythium. The following is from Mr. Butler:^ 



The earliest sign is the alteration in color of one of the leaves, usually one of those 

 recently expanded toward the center of the bud. This turns white and soon after- 

 wards commences to wither. Other leaves are attacked in turn; the heart of the bud 

 is reached, and the whole top withers and falls off, the last stage being reached only 

 after a considerable time. 



The leaf sheaths of all diseased trees are marked by irregular sunken spots in greater 

 or less number. In the earlier stages, and particularly in the inner layers where 

 young ones are often numerous, the spots are white ; later on they become brown . They 

 are always sunken and usually have somewhat raised edges. They begin on 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. 

 In all cases, however, the first appearance is on the outer sheaths. The earlier patches 

 are dry and either free from any appearance of a parasite on tlie surface or covered 

 with a white mycelium 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 



1 Coleman, Leslie C. Op. cit., p. 54. 2 Coleman, Leslie C. Op. cit., p. 58. ^ Butler, E. J. Loc. cit. 

 228 



