Vol. IV. No. 80. 



THE AGRICULTURAL NEWS. 



13.5- 



WITCH BROOM DISEASE OF CACAO. 



Tlie following article contuining hint.s for the 

 treatment of the 'witch broom' disease of cacao appeared 

 in the Demerara Daih/ Chronicle of April 19: — 



Since it has become known to the puhhc that 'witcli 

 broom' has been found b}- the Government Rutanist and the 

 Instructors in Agriculture on an estate up the Demerara 

 river, it behoves all cacao planters to keep a sharp look-out 

 for this destructive fungoid disea.se, which has done so much 

 damage to the cacao industry in Surinam. As far as is 

 known, the disease is only on one estate in the colony, and 

 it is with the idea of preventing it from spreading to other 

 estates, that these notes are written. 



THE SYMPTOMS OF THE DISEASE. 



'Witch broom' consists of curiously swollen, gouty and 

 abnormal twigs, bunched together and growing in tufted 

 masses from the normal stems of the tree. The trees, when 

 attacked, very soon give up bearing healthy pods, as the 

 pods of a tree attacked by 'witch broom' are themselves 

 attacked by a fungus which makes them become hard and 

 v.ciody and absolutely useless. The productiveness of the 

 tree is so seriously impaired that it is fonnd most advisable 

 to cut down any tree that may be attacked and to burn it, 

 with the hope of checking the spread of the disease. 



The disease seems to have been first noted in 1898 

 when, it is understood, specimens were forwarded to Professor 

 Ritzema Bos, of Amsterdam, who discovered fruiting organs 

 of the E-irxisciis type, on the underside of some of the 

 rudimentary leaves borne on the tufts of 'witches' broom.' 



Profes.sor Ritzema Bos considered that the disease was 

 due to a new fungus. The disease has been studied by 

 Professor F. C. Went, of the University of Utrecht, who 

 came out to Surinam, so as to be able to study it on the spot. 

 The conclusion that he came tr> was that the disease was due 

 to a fungus, but he was unable to .say, with any degree of 

 certaint}-, what that fungus was — owing to the fact that he 

 had been unable to observe any formation of spores. 



KEMEDI.VL MEASUEES. 



Although little scientifically may be known of the 

 disease, planters know that an estate overrun with this 

 fungus is practically worthless. As the fungus that produces 

 this disease is so little known as to he not yet named, no 

 .'spores having been observed, it is difficult to suggest any 

 remedial measures beyond the 'axe and fire-stick.' But 

 planters can adopt preventive methods, and we would 

 strongly advise every cacao grower, on the Demerara river 

 especially, to adopt some methods C'f a preventive nature. 

 The following measures should be adopted to keep trees in 

 as healthy and as sound a condition as possible. Healthy 

 and vigorous growing trees arc the least likely to be attacked 

 by any prevailing disease. 



PREVENTIVE MEASUEEs. 



1. Attend more carefully to your pruning. Follow your 

 pruners and insist on their making clean, smooth cuts, close 

 to the stem, and well rounded, so that the bark has every 

 chance of healing over the scar. 



2. Tar all wounds and cuts. 



3. Remove all diseased pods and branches and burn. 

 them. All old shells and pods should be buried, with 

 a little lime, and not allowed to remain in the fields — hot- 

 beds for any fungoid diseases. If burning the pods be too 

 expensive or inconvenient, break them at the factory and 

 throw them (if your estate is on the river's bank) into the 

 river, to be taken awav with the tide. 



4. Improve the health of your trees by careful forking; 

 and by keeping 3'our estate ircll draincl. Bad drainage is- 

 at the bottom of many more diseases than you would think 

 possible. 



•"). Do not overshade your trees. 



6. Have a daily watcli kept for the first signs of this- 

 disea.se, and should it apiiear on any tree, cut it out and 

 burn it at once. 



A MODEL CACAO ESTATE. 



One of the best-drained cacao estates in the colony is- 

 plantation Coverden on the Demerara river, and although 

 the area is large, consisting of nearly 340 acres, yet this 

 estate is singularly healthy and almost free of any dangerous- 

 fungoid disea.ses. This is duo to the good drainage of the- 

 estate, and to thorough and good cultivation. Let all 

 cacao growers bear this in mind and give their trees the 

 best of drainage and the best of cultivation that their 

 means can afford. 



SPECIMENS OF WITCH BROOM. 



It is advisable for growers to pay a visit to the oflftce of 

 the Government Botanist, for the purpo.se of seeing specimens- 

 of ' witch broom ' so that, should it appear on their estates, 

 they would at once recognize the disease. It has to be seen 

 but once, when it will bo readily recognized on any other- 

 occasion. 



ECONOMIC PLANTS FOR SALE. 



The following is a list of ocon(.imic plants in pots 

 (and in beds) available for sale at the Botanic Station,- 

 Grenathi. Applications from other colonies should 

 be addressed to the Hon. the Colonial Secretary, 

 St. George's, Grenada. The cost of the plants vary 



from If?, to 3f?. each — p; 



Achras Sapota 



(Sapodilla or naseberry) 

 Acoumar (Timber) 

 Anona muricata (Sour sop) 



,, .squamosa (Sweet sop 



or sugar-api>le) 

 Anona Cherimolia 



(Cherin-ioyer) 

 Averrhoa Carambola 



(Carambola) 

 Basel la cordifolia 

 Blighia sapida (Akoe) 

 Carica Papaya (Pn-paw) 

 Castilloa elastica 



(Central American Rubber) 

 Casuarina equisetifolia 



acking and freight e.xtra : — 



Cola acuminata (Kola) 

 Enterolobium Timbouva 

 Eugenia caryophyllata (Clove) 

 Funtumia elastica (African 



Rubber tree) 

 Ficus Yogelii 

 Hevea brasiliensis (Para 



Itubber) 

 Jatropha multifida 

 JIangifera indica (ilango)- 



(Grenada Ceylon) 

 iMangifera indica (Grafted) 



Ceylon, No. 2. 

 Mangifera indica (grafted 



Pesters) 

 JIangifera indica (\-arious 



kinds) 



Catalpa longissima 

 Cedrela odorat<i (West Indian iMelicocca bijuga (Genip)- 

 Cedar) ]\Iyristica fragrans (Nutmeg) 



Citrus Aurantium (Sweet Passitlora laurifolia (Water- 

 Orange) lemon) 

 ,, ,, (var. Portugal) Pereskia aculeata (Barbados 



„ ,, (var. Navel gooseberry) 



budded) Persea gratissima (Avocado- 

 ,, noblis (var. Mandarin) Pear) 

 „ ,, (var. Tangerina) Psidium Gua.va (guava) 

 ,, medica (var. acida) Sapindus inaequalis 



Coffea liberica (Liberian Terminalia Catappa (Almond) 



Coffee) Theobromi Cacao (Cacao) 

 „ arabica (Arabian Coffee) Vanilla planifolia (Vanilla) 

 ., stenophylla 



