Plant Sanitation, 



558 



fDECEMBER, 1908. 



in 1905: — " Mr. Cradwick has been engaged 

 at intervals during the last two years 

 in applying various remedies suggested 

 by me. These experiments are still in 

 progress, but I may say that I find the 

 most effectual remedy is to spray with 

 Bordeaux mixture at intervals of six to 

 nine months until there is no trace of 

 the disease." The mixture used was— 



Copper sulphate... pounds 6 

 Lime ... ... do 4 



Water gallons 50 



The same report states that " in Grand 

 Cayman and in parts of Jamaica planters 

 have not been successful in growing 

 coconuts because the young plants die 

 off just at the time of the first flowering." 



F. A. Stockdale, of the Jamaica Stations 

 reported in 1907 on the bud rot in 

 Trinidad :— 



"The youngest leaves appear to stand 

 upright and do not unfold as they 

 should. Afterward they turn yellow 

 and then brown in colour, aud the whole 

 appearance is that of a withering tree 

 with the centre of the cabbage in an un- 

 healthy condition. Sometimes this dying 

 of the central bud could not be noticed un- 

 til many of the lower leaves had turned 

 yellow or brown. . . . After a time 

 the terminal bud falls over, frequently 

 leaving a ring of quite healthy-looking 

 leaves at the top of a "headless " trunk. 

 . . . This rot, in a diseased palm that 

 is still standing is invisible until the 

 harder outer coverings of the bud are 

 removed, and it is found to be limited 



to the softer tissues A badly 



diseased bud is generally full of fly 

 larvie, etc., and the smell is awful. 

 . . . Microscopic examination of the 

 roots and stem indicated that they were 

 quite normal, while those portions of 

 the terminal bud, in the advancing 

 margin of the disease, showed in most 

 cases bacteria of different kinds, only in 

 two instances was the advancing margin 

 marked by a reddish discolouration 

 produced by some fungus mycelium. 



The few isolated cases in the Cedros 

 district would indicate that this disease 

 is not of a very infectious character, 

 but large numbers have been killed out 

 in the Siparia district, the spread being 

 very rapid aud apparently from the 

 windward, I am inclined to the view 

 that this disease is similar to the 

 destructive disease of coconuts in Cuba, 

 but as far as Trinidad plantations are 

 at present concerned, it would appear 

 to be largely due to unfavourable con- 

 ditions of soil, drainage, etc 



With our present knowledge of the 

 nature of the disease it is impossible to 



suggest a remedy for trees that are 

 already infected, and therefore steps 

 must be taken for preventing its spread. 

 It is suggested that the top 4 or 5 feet 

 should be cut from the diseased trees 

 and buried deeply with lime." 



Bud rot appeared in Ceylon in 1906, 

 and is reported by Petch. It was found 

 only in a small isolated patch of 10 acres, 

 about 800 trees, of which 50 were dead 

 or dying. The infected trees were 3 or 4 

 years old, and old trees were not found 

 ailing. 



" The first indicaion of the disease (in 

 the case of young plants) is the wither- 

 ing of the youngest unfolding leaf. 

 This turns brown and can be pulled 

 out of its sheath ; it is then found to 

 end in a soft brown mass. . . . The 

 decay of this leaf is followed by that 

 of the other fronds in succession, com- 

 mencing with the youngest aud proceed- 

 ing outwards and downwards. The 

 fronds decay aud fall off until only a 

 conical stump remains. If the dying 

 fronds are removed and the bud exposed 

 there will be found instead of the 

 white cabbage a pale brown semi-liquid 

 mass which becomes dark brown with 

 age and possesses an odour resembling 

 that of a tanyard. In an advanced stage 

 this rot includes the whole of the cab- 

 bage, and stops only when the woody 

 portion of the stem is reached, 



"The organisms responsible for this 

 decay are bacteria which are found in 

 abundance in the rotting tissues ; they 

 are short, thick rods with rounded ends 

 which form whitish colonies of slow 

 growth on sugar agar. . . . These 

 bacteria appear to find an entrance to 

 the cabbage along the youngest leaf. 



" Diseased trees should be felled and 

 the terminal bud burned. They should 

 not be allowed to lie on the ground 

 and become dry. ... If steps are 

 taken to remove dead and dying palms 

 as soon as they are observed, there need 

 be no fear that this disease will become 

 a serious menace to coconut cultivation. 

 Felling and burning diseased trees is 

 no doubt an expensive process, but it 

 must be remembered that the work is 

 of the nature of an insurance effected 

 on the remaining trees, aud its cost 

 should be estimated in terms of the 

 survivors instead of being compared with 

 the actual value of the trees destroyed." 



Close planting favours the spread of 

 the disease, by preventing the evapor- 

 ation of moisture from the young shoots. 



The bud rot in East Africa is known 

 from a letter cited by Petch, who quotes 

 from it :— 



