4334, 4342, May, 1912, 4351, Feb. 3, 1914, 1342, Nov. 28, 191G, 5816, 

 Feb., 1917, 6313, 6403 ; Ponce, Jan. 11, 1912, 4150, 4155, 4160 ; For- 

 tuna, April 27, 1912, 4356 ; Fa jardo, March 25, 1912, 4292 ; Yauco, 

 March, 1912, 4299, 4300 ; Canovanas, May 29, 1912, 4343 ; Carolina, 

 Jan. 9, 1915, 2521. On Carica papaya, Rio Piedras, Oct. 24, 1912, 

 4645, Dec. 1912, 4731. Common in all parts of the Island on dead 

 and dying cane stalks and leaves. (PI. XX, fig. 4; pi. XXVIII, fig. 

 9, 13, 14, 16, 17.) 



RIND DISEASE {Melancomum sacchari). 



The rind disease of cane has been the subject of a paper recently 

 published in this Journal (52) and was there treated in .such detail 

 as to make it unnecessary to give more than a summary for the sake 

 of completeness in the present account. 



Rind disease has been reported and studied under a variety of 

 names and with much confusion with other fungi,, (in particular with 

 Thielaviopsis) , in practically all of the cane growing countries of 

 the world, including Louisiana, Georgia, Texas, Florida, Cuba, Ja- 

 maica, British Guiana, Barbados, Trinidad, St. Vincent, Antigua, 

 Grenada, St. Lucia, Nevis, Argentina, Brazil, ^Mauritius, Java, Indo- 

 China, Queensland, New South Wales, and Hawaii. In some instances 

 it has been considered as a serious parasite, and in particular has 

 been held to be the cause of a serious epidemic of disease wliieli nearly 

 destroyed the cane industry of Barbados in 1895-99. i\Iost workers 

 are now agreed, however, that as a general rule Melanconimn is but 

 a wound parasite or an enemj- of weakened or over-mature canes. 

 This view is held for Porto Ricrai conditions where it is one of the 

 commonest, if not the commonest fungus present in the cane fields. 



Circumstances under Avhich the rind fungus have been noted in 

 Porto Rico are extremely variable. It has never been observed in 

 fields of young green cane excepting in shoots injured or killed by 

 some other fungus such as Marasmius sacchari or by such insects as 

 the changa, white grub, or the moth stalk-borer. In such cases it 

 is certainly only a saprophyte. 



In cane of six or eight months, it can commonly be found on the 

 leaf-sheaths of many stalks and especially on certain varieties. The 

 fungus occurs not only at the base on the outside of the leaf-sheath 

 but occasionally near the union of the leaf-sheath Avith the leaf-blade. 

 On the leaf-sheaths it may hasten the dying of the leaf but does not 

 necessarily pass from the sheath into the stalk. Numerous canes have 

 been watched 1o maturity, which remained perfectly healthy as far 



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