238 



THE AGRICULTURAL NEWS. 



July 20, 1912. 



FUNGUS NOTES. 



A BUD DISEASE OF THE COCO-NUT 



PALM IN MEXICO. 



The important bud rot disease of coconuts has occupied 

 considerable attention of late, and the recent work of 

 Johnston attributing it to JJacillus coli was reviewed in the 

 Afjriindtural News, Vol. XI, pp. 94 and 110. This work 

 wa.s done on the form of the disease that occurs in the West 

 Indian Islands, and does not necessarily apply to all such 

 diseases. In the Agricultural News, Vol. X, pp. 14 and 30, 

 some account was given of a bud roc of palms in India 

 attributed by Butler to Pyfldum palmivorum, and it was 

 stated that one of the species occasionally subject to this 

 disease was the coconut. In the English section of the 

 Eenei" of Tro/'ical Agriculture, Vol. II, p. 29-5, appears an 

 article by Olssen-Seffer on a bud rot of coconut palms in 

 Mexico, particularly prevalent on the east coast. This 

 disease the writer attributes to Pi/t/mu/i pabnivorwin, the 

 cause of the Indian disease already referred to; as will be 

 seen from the account which follows, the Mexican disease 

 differs somewhat in its symptoms from the accounts given of 

 the West Indian disease, particularly in the appearance of 

 brown stained spots on the bole of the tree, in the exudation 

 of gum from these spots, and in the fact that the outer leaves 

 appear to decay first and not the central spike. Olssen-Seffer's 

 account is as follows: — 



'As far back as 1898 a disease similar in its effects to 

 the destructive "bud rot" disease of cocoanut palms in the 

 West Indies, was known on the eastern coast (of Mexico), 

 killing out the cocoanuts in many districts. 



^Bud rot due to a fungus. The parasite which is respon- 

 sible for the disease is a fungus {Pythium 2Mdiitirorum, Butl.), 

 which gains entrance through the leaf sheaths which closely 

 encircle the green tops of the stem below the point where the 

 expanded leaves open out into the spreading head. Its 

 principal characters of importance — from the point of view 

 of treatment — are that it only emerges from the tissues 

 of the leaf sheaths, to form spores in the inner layers of 

 sheaths, and that hence in the early stages liefore the dead 

 stalks drop off, it is not exposed to conveyance by the wind. 

 Furthermore, on account probably of the sugary nature 

 of the palm saps, its track is rapidly followed by hosts of 

 putrefying organisms which not onlj' lead to the putrid heart 

 rot of dead trees, but also rapidly destroy by "poisoning" the 

 parasite itself with the probable exception of its durable 

 spores 



'The spores of the parasite are of two kinds: a temporary 

 form suited for very rapid propagation limited in time and 

 space and quite ephemeral, and a lasting or durable form 

 whose structure shows it to be well capable of withstanding 

 adverse circumstances and probably of living many months. 

 'The full history of the latter is not yet known but it is 

 the proliable agent of extensive as opposite to intensive 

 infection. It is possibly capable of surviving even the 

 putrefaction of the bud which the rest of the fungus cannot 

 do, and after exposure by complete rotting of the "cabbage" 

 may be conveyed to fresh trees and secure their infection. 

 Water is necessary for the germination of the spores, but 

 rain drops or the film of dew in cold weather is suffici- 

 ent. Cases of infection are rare in the dry season, and 

 take place chiefly in the cold weather (when there is 

 much fog and dew), and to some extent during the rains. 

 The conditions necessary for the spread of disease are 



(1) the exposure of the diseased inner leaf sheaths to the air 

 (with some animal bird or insect capable of conveying 

 infective matter); (2) the prevalence of moist or foggy 

 weather or copious dew, to allow of germination of the spores. 



'I find (1) the first symptom visible is a slight brown 

 discoloration on the back of the centre rib of the heart limb; 



(2) as each limb appears it is more and more discoloured; 



(3) a brown stain appears in spots upon the bole of the trees; 



(4) later a clear gum appears in great gouts and hardens on 

 each discoloured spot on the bole; (5) all the outer limbs of 

 the tree begin to drop down: (6) the young blossoms of the 

 trees show signs of brown decay; (7) the whole spike of 

 heart leaves leans over and finally drops right out of the tree; 

 (8) the tree is dead. 



'I have observed the following also: (1) the trees ap- 

 pear to die in patches of three or four, (2) the trees never die 

 on a hillside; (3) the land where they die has always been of 

 a yellowish clay. 



'The treatment recommended. The first circumstance can 

 be prevented by destroying all diseased heads in the early 

 stages, before the "cabbage ' falls apart, the second seems at 

 present beyond human control, except that poison can be 

 applied to the seat of new infection; on these considerations 

 the treatment is based. I am confident that the burning of 

 diseased tops, thoroughly carried out, will in itself be suffi- 

 cient to check the disease.' 



THE PASTEURIZATION OP MILK. 



MEANING OF THE TERM 'pa.steueization'. Pasteuriza- 

 tion as applied to milk is the process of heating for a short 

 or long period as the different methods demand at temper- 

 atures usually between 140° and 185° F. The process must 

 be followed by rapid cooling. The term originated from the 

 experiments of Pasteur, in France, from 1860 to 1S64, on 

 the 'diseases' of wine, in which he found that the heating for 

 a few moments at a temperature of 122° to 140° F. was 

 sufficient to prevent abnormal fermentations and souring in 

 the wine. A little later Pasteur found that by a similar 

 heating beer could be preserved from souring. The applica- 

 tion of the process gave rise to the term Pasteurization. 



VALUE OF rASTEUiiiZATioN. The value of pasteuriza- 

 tion from a sanitary standpoint is of the greatest importance 

 when market milk is under consideration. 



In the first place, the pasteurization of milk, when the 

 process is properly performed, affords protection from 

 pathogenic organisms. Such disease-producing bacteria as 

 Bacillus tuberculosis, B. typhi, B. diplitlieriae, and the 

 dysentery bacillus, are destroyed, or at least have lost their 

 ability to produce disease, when heated at 140° F. for twenty 

 minutes or more. Although the infective agent in scarlet 

 fever is unknown, epidemics of the disea.se ha^c been traced 

 to milk supplies, and in such cases pasteurizuii 'ii has been 

 resorted to as a means of safeguarding the public, with 

 apparently satisfactory results. 



In the second place, pasteurization causes a reduction of 

 the infantile death rate due to the ordinary intestinal dis- 

 turbances. Numerous experiments definitely prove the value 

 of pasteurization in this connexion. While it has not been 

 possible to isolate any special organisms which act as the 

 causative agents in the common infantile intestinal troubles 

 other than the one producing dysentery, it seems that high 

 bacterial numbers in the milk consumed are associated with 

 such diseases. 



In the third place, pasteurization is of value from a com- 

 mercial standpoint in so far as it increases the keeping quality 

 of the milk and prevents financial losses caused by souring. 



