Vol. IV. No. 79. 



THE AGRICULTUEAL NEWS. 



117 



THREAD DISEASE OF CACAO. 



In a previous i.ssue of the Aijricultural Kev's (Vol. Ill, 

 p. 281) mention was made of a new disease then recently 

 reiiorted on cacao on one estate in St. Lucia. Information 

 was asked from readers of this journal as to whether the 

 disease occurred in any other localities and as to what 

 (if any) wild trees or bushes it attacked. The agricultural 

 officers in the different cacao-growing islands were also asked 

 to obtain inforniation on these two points. 



It was mentioned that there were two forms of the 

 disease, namely, tlie ' thread ' and the 'horse hair.' It is 

 possible, though not likely, that the two forms are two 

 distinct diseases. The thread blight is the more destructive 

 of the two forms. 



At the Agricultural Conference held at Trinidad in 

 January, a short note was read by ilr. L. Lewton-Brain, 

 B.A., F.L.S., Mycologist on the staff of the Imperial Depart- 

 ment of Agriculture, dealing mainly with the thread disease ; 

 the full note will be published, togetlier with other Conference 

 papers, in the West Indian Ihdh-tin. fJreat interest appeared 

 to be taken by delegates in the i)resence of a hitherto 

 unrecorded disease of cacao in the West Indies. Specimens 

 were exhibited by Mr. Lewton-ljrain and by ilr. G. 8. 

 Hudson, the Agricultural Instructor at St. Lucia. Subse- 

 quently, the disease has been reported from a cacao estate 

 near Sangre Grande, in Trinidad ; it is now known also on 

 another estate in St. Lucia. Quite recently Mr. A. W. 

 Bartlett, Superintendent of the Botanic Gardens in British 

 Guiana, has reported the discovery of this disease on 

 a neglected estate on the Demerara river. 



In St. Lucia the manager of the estate where the disease 

 was first noticed states that the damage done was very 

 considerable, and both he and ilr. Hudson report that the 

 fungus quickly kills every young twig and every leaf it 

 touches. In Trinidad the damage is said not to be very 

 severe. 



The fungus of the thread blight appears as dark-brown, 

 branching strands running along the twigs, so closely 

 attached to the bark that they cannot be removed without 

 tearing this away. The young threads are white and more 

 delicate. A thread will [lass along the .short leaf-stalk and 

 when it reaches the blade, will branch out into fine threads, 

 which at first follow the main ribs of the leaf. 



The threads are composed of numerous closely woven, 

 but for the most part parallel, hy[)hae of a fungus. From 

 the under side of the threads are given off numerous single 

 hyphae which grow into the crevices of the bark. These 

 Iiyphae seem unable to pierce a well-ffirmed cork layer, but 

 can enter a very young twig ; when they do so the cortex is 

 destroyed. The tissues of buds and leaves are also entered 

 and destroyed. 



Mr. Hudson repoi'ts that in St. Lucia the fungus appears 

 on a great variety of forest trees, including 'pois doux' 

 {Inga lauriiia), ' bois de basse ' (Coli/jitrcdifltes sericea), and 

 ' bois Creole.' In Trinidad the fungus attacks the 'immortel' 

 tree used for shade. 



The fungus probably spreads mainly by means of its 

 mycelium, attached to bits of dead twigs, leaves, etc. Birds 

 may carry the strands from one locality to another. 



In St. Lucia the disease, where it has been noticed, has 

 been stamjied out by prompt and thorough pruning. So 

 much .so, that in .lanuary it was not possible to get specimens 

 of diseased cacao twigs for exhibition. The specimens 

 exhibited by Mr. Hudson at the Agricultural Conference 

 were taken from the wild host plants. It is to be hoped 

 that similar prompt measures will be taken wherever the 



disease is noticed, as there can be little doubt that, when 

 neglected, great damage may be done very quickly. 



It is of importance that the distribution of the disease 

 in the West Indies should be known as accurately and fully as 

 possible. If any of our readers should notice it either on 

 cacao or on any of its wild host plants, it is requested that 

 they will communicate immediately with the local officers of 

 the Imperial Department, giving all the information possible 

 as to damage done, external conditions, affected locality, etc. 

 Dried sjiecimens of diseased twigs and leaves should also be 

 sent for examination at the Head Office. 



Though pruning, so far, has proved an efficient treatment 

 for this disease, there may be cases where this would have to 

 be too severe for the health of the trees; fungicidal treatment 

 might prove successful and is recommended for trial. 

 A similar disease of tea in India, known also as ' thread 

 blight' has been shown to yield to treatment with a lime- 

 suli>hur wash ; full particulars of this wash can be obtained 

 on application to the Head Office, Barbados. 



DOMINICA. 



Hints to Intending Settlers. 



The ibllowinCT circular, signed by the Secretary 

 of tire West India Committee, has been sent to the 

 heads of some 200 schools and colleges in England. 

 The publication referred to was issued as No. 24 of 

 the pamphlet series of this Department : — ■ 



I beg to send you herewith a copy of a pamphlet 

 entitled ' Dominica : Notes and Hints to Intending Settlers,' 

 compiled by his Honour H. Hesketh Bell, C.M.G., Adminis- 

 trator, which deals very fully with the advantages offered by 

 that island to young and active men with a moderate 

 amount of capital at their command. 



May I ask you to be good enough to luring this small 

 book before the notice of such of those with whom you are 

 in contact, who are considering the career upon which they 

 will enter after the termination of their studies ? 



Alreadj-, during the past tew years, a large number of 

 settlers of the best class have devoted themselves to the 

 cultivation of cacao, limes, and rubber in this beautiful 

 island, and it is with a view to increase this number that 

 I venture to trouble you, and I shall be glad to know if the 

 action we are taking meets with your approval. 



I need hardly add that I shall be most happy to 

 answer any inquiries which you may wish to make 

 regarding this fertile colony. 



TOBAGO STOCK FARM. 



The (Jovernment Stock Farm at Tobago contains 

 the following stud animals : — 



1. Government stallion (thoroughbred), ' Serpa Pinto.' 



2. Government sire donkey, imported from Spain, 14 

 hands high. This donkey is introduced for the production 

 of mules for which there is an excellent demand at remunera- 

 tive prices. 



3. Bulls of the following breeds : — Imported Hereford, 

 pure-bred Zebu, crnss-bred Red Poll, and Guernsey. 



4. Imported Shropshire ram sheep. 

 •5. Imported Berkshire boars. 



Inifiorted heifers for breeding can be purchased at 

 ordinary market prices, also young thoroughbred Berkshire 

 pigs. Eggs from imported Plymouth Rock fowls can be 

 purchased at 2s. per dozen. 



