osf; 



THE AGEICULTUEAL XE^^■S. 



AiGii^T -2'.). 1914, 



FUNGUS NOTES. 



COCO-NUT BUD ROT IN INDIA. 



Further iiifDriiiatinn re.speetiiig l>ud rot of coco-nut palni,< 

 ill MalaViar is contained in two recent papers by F. .J. F. Shaw 

 and 8. .Sundararanian in the Af/ricultural Journal of Indii 

 <Vol. IX, pp. 111-117) and Annates Mr/roloinci (Vol. XII, 

 pp. lT, 1-261'). 



While diseases sntticientl^y alike in their general symp- 

 toms to be described as bud-rot occur both in the West Indies 

 and in India, there has been a strong tendencj- for mycolo- 

 gists working in the former region to attribute the disease 

 occurring there to bacteria, and for those in the latter country 

 to definitely associate the Indian form with fungi, a difference 

 of results which becomes .sharper as investigations proceetl. 

 Although it cannot be said that the causation of the West 

 Indian di.sease has been proved to he confined to any one 

 jiarticular bacterium, yet consideration of the work of 

 Johnston, Korer and others (see Aiiricultuml Kefs, Vol. XI, 

 pp. 94 and 110) makes it appear quite certain that the di.sea.se 

 can be and is produced without the intervention of a fungus. 

 It .seems to be tlie case that there are at least two distinct 

 diseases with similar .symptoms, the one l>acterial and the 

 other, as will be seen, due to Pythium 2Mlnuvorum. The 

 latter has not yet been met with in the Western Tropics. 

 We cannot speak .so definitely with regard tC' the non-occur- 

 rence of the West Indian form of disease in the East, in view 

 of the description by Fetch of a bacterial bud-rr.t in Ceylon, 

 which may or may not be the same. 



Two palm di.seases in India have previously been made 

 the subject of detailed investigation, one a disease of the 

 Areca palm {Areca catechu) due to Phytojihthora omnivora. 

 var. Arecae (see Af/riculturnl Siwr. Vol. X. p. 206) and the 

 other a bud-rot of the Palmyra palm ( fioiassus flahdliier) 

 due to Pythium palmivorum, Butl. {Ar/rtcultural Nevs.Xol- X. 

 pp. 14 and 30). Each of these diseases has made serious 

 ravages in certain districts. 



The papers now before us deal with an extension of the 

 Palmyra disease to coco-nut palms. In the Godavari district, 

 where the epidemic on the Palmyra is most severe, it had 

 been noticed that coco-nut palms were liable to be attacked, 

 but )iot to any .serious extent — a result attributed tr. the 

 more woody nature i:>f the latter. 



In the year 1912, a serious disease of coco-nuts in 

 Malabar began to attract attention, and has been since found 

 to lie common in the district, affecting coco-nut pahns of all 

 ages. The disease appears to be of about ten years standing, 

 and its progress is slow. 



The first notable symptom is the collapse of the central 

 leaf, which turns browTi and dies. The older leaves droop 

 and fall oft' as the disease progresses. A characteristic sign of 

 the disea.se is the presence of a row or rows of brown spots 

 .stretching across a leaf, produced by the fungus eating its 

 way through the fnlds of the leaf while it is still in the bud. 



The fungu> Pythium paliiuroru/ii is abundant in all the 

 diseased tissues, and produces al>undant sporangia, the spores 

 from which are washed down by rain and spread the infection. 

 Inoculation experiments from pure cultures have established 

 a causative connexion between the fungus and the disease, 

 and have further .-ihown that the condition of successful 

 infection is a .state of saturation of the bud and the surround- 

 ing air with water. 



The climate of Malabar in the month.> of June, July 

 and August is such as to amply .satisfy this condition. As 

 mea.sured at one station the average rainfall for twelvemonths 

 is 169 inches, of whidi 128 inches fall in the three months 



named above. The climate of the Godavari i- much drier 

 and this is regarded by the authors as the reason for the 

 relative freedom of coco-mit i)alms from the disease in that 

 district, in .spite of its abundance on the more easily infected 

 Palmyra. 



No treatment r>f the disea.sed trees is regarded as feasi- 

 ble; their vigorous and ruthless destruction is advocated a.s- 

 the surest and cheapest means .if dealing with the outbreak. 



CACAO CULTURE IN THE BELGIAN 

 CONGO. 



In the Bulletin Aiiricih du Conj/o Belye for June 1914,. 

 an intere.sting and important article, by Mons. J. Clae.ssens^ 

 appears, dealing with the cultivation of cacao in the region of 

 the Belgian Congo known as Mayuml>e. At pre.sentin this terri- 

 tory there are 3,-500 hectares under cacao one to si.xteeu 

 years of age: this is approximately 8, .500 acres in young cacao, 

 and since it is further shown in the article under review that 

 planting is still going on, one is led to suspect that, like the 

 Gold Coast, the Belgian Congo may in time become a formi- 

 dable competitor* on the cacao market, and one more to lie 

 feared by the West Indies. 



The first few pages of the article contain information 

 relating to the climatic conditions under which cacao 

 grows in Mayumbe. The mean temperature is 24-56' C. 

 and the annual rainfall was for 1913, 1,123-2 mm. 

 which is .somewhat below the average. Wind intensity is 

 also referred to. and attention is called to the (juestion of 

 humidity. The atino.sphere generally contains considerable 

 moisture, and it is .said that it is owing to this ciicumstance 

 that the cacao can exist through four to five months of dry- 

 ness which is experienced e\ery year. After describing the 

 characteristics of the soil, the article proceeds to discuss the 

 clearing of land and the provision of .shade. In cutting down 

 the forest trees, the plan is adopted of saving the more u.seful 

 trees, like oil palms; and thfise trees like Eriodentlron, which 

 have a very high habit, are also saved for the shade and 

 shelter they pro\-ide. In discussing the question of shade, it 

 is agreed that this is necessary for young cacao, but as soon 

 as the trees themselves have covered the soil, artificial shade 

 is then di.spen.sable. This is the general view held in most 

 parts of the tropics. It will be admitted, however, that the 

 presence of shade trees on cacao estates performs more than 

 a single function, i.e., the reduction of temperature. ()n wet 

 land shade trees act as di-ains, and in windy places aftbrd 

 .shelter. These factors, though not di.scussed in the article 

 under review may, nevertheless, be taken into consideration 

 in connexion with the views therein expressed, as may also 

 the correlative circumstance that certain shade trees like 

 'Pois doux' which in estate ])arlance 'suck the land' and are 

 therefore undesirable where the soil is at all liable U< dry out. 



The variety of cacao cultivated in Mayumbe is the 

 Amelonada, a variety that ririginated in San Thome. It is. 

 said to be very productive and resistant to pests and diseases, 

 the principal ones being Sahlbergella singularis and Phytoph- 

 tora Faberi. 



Con.siderable space is devoted to the suliject of fermenta- 

 tion. This process, or rather .series of processes, lasts five to^ 

 eight days. The beans are dried directly they are brought in. 

 Washing has been tried liut abandoned. The planters of 

 Mayuml.ie u.se several methods for drving (a) in the sini, mi 



* The expiirt.iti'Hi 'f racan beans fiuni Mayumbe has risen 

 fr.iui 14.;5(Mi kilos HI l'.mL>. t.. '.»(-i7..snii kilM>. ii, Kti:! (I kil.i = 

 2-2 ft.) 



