Vol. IX. No. 214, 



THE AGRICULTURAL NEWS. 



219 



TRINIDAD : BOARD OF AGRICULTURE. AN- 

 NUAL REPORT OF THE MYCOLOGIST, lUoU-jn. 



This report contain.^ much interesting information with 

 regard to diseases of the principal crojis in Triaidad, arrived 

 at as a result of Mr Uorer's first year of work in that island. 

 The plants dealt with include cacao, sugar-cane, cocoa-nut 

 pahns, and banana.s, in addition to several of minor 

 importance. 



The work on cacao consisted of cultural and inoculation 

 e.xperiments with the black rot funaus {Piii/lophthuni minii- 

 vora) and various species of Nectria. As a result of these 

 experiments, it was shown that cacao canker, as w-eli as 

 black rot of the pods, is due to the first-mentioned fungus, 

 and that infection may spread from the pods to the cushion 

 and bark, and vice versa. A fuller paper deaRng with this 

 point is to be published later. Some investigation of minor 

 disca.ses such as die back, thread blight and root disease, 

 was also made, and material suspected of exhibiting the 

 characters of the witches' broom disease of Surinam was 

 carefully examined, with the result that it appears unlikely 

 that this disease occurs in Trinidad. Careful spraying 

 experiments on cacao were carried out in September and 

 December o( last year, and in February of this year, as 

 a re.->ult of which Mr. liorer is able to state that spray- 

 ing, if thoroughly conducted, pays; for it not only 

 naturally increases the number of healthy pod.s, but also 

 jirevcnts loss of trees from canker, by checking the spread of 

 the black rot fungus on the pods, and from these to the tree 

 itself. It also has a beneficial etiect in keeping the minor 

 diseases in check. A paper dealing fully with the results so 

 far attained is to be issued later, and should prove of great 

 interest. 



As a result of the field examination , of sugar-cane, 

 !Mr. liorer states that the root di.sease and the blight 

 are not connected with one another, as one may occur 

 without the other, though both are sometimes found 

 in the same field. A fungus, identified by ]\Iassee as Srjttn- 

 ri/liiiJnam xusjicHinii, was found on dead adult frog hoppers 

 and may prove to be of economic importance if it is capable 

 of causing disease of living insects. (See Few Bulletin, 

 1910, No. 1.) 



Bud rot and root disease are the most serious diseases of 

 cocoa-nuts in Trinidad, though their causes or cause are not 

 yet definitely determined. It is suspec!ed that some connexion 

 may exist between them; that both are due possibly to the 

 same organism. The only method of dealing with them is 

 thoroughly to destroy infected trees, and for this purpose 

 a sum of ^375 has been so far expended on work under the 

 direction of an inspector. Mr. Uorer recommends that the sum 

 of ^oOO, originally voted, should be voted again, and that the 

 work .should be continued next year, when he also proposes 

 to make a more thorough investigation of the diseases. Other 

 cocoa-nut diseases are bleeding disease of the stem, due to 

 Thiclnviojisis ethnceticiis, and leaf disease, in addition to one 

 known as 'little leaf di-sease', the cau.se of which is not under- 

 stood. 



Three banana diseases are reported: the Panama disease, 

 possibly due to a .species of Fusarium; the Moko disease, shown 

 by Mr. Uorer to be bacterial in origin; and a root disease, 

 caused by a species of Marasmius, which is probably that 

 known as Marnsinius semiustus. 



Anthracnose of mangos, due to Ghieoip yrium mangit'erae, 

 was of rather common occurrence. The fungus attacks the 

 flowers and leaves, as well as the fruit. If this fruit and the 

 avocado pear are to be grown for export, on any industrial 

 scale, a policy of thorough spraying will have to be adopted. 

 Leaf spot disease of cassava, leaf mould of tomatos due to 

 Cladosjjoriicm ftdmim, and rose mildew are also mentioned, 

 but were controlled on a small scale by spraying. Weak 

 lime sulphur mixture is recommended for roses, and Bordeaux 

 mixture for tomatos. 



As will be seen, the report contains much valuable 

 information. Some of it has already appeared in the Biillelin 

 of the Department of Aijriculture, Trinidad, and part of this 

 will be incorporated into suitable articles under the heading 

 of Fungus Notes, so as to render more details available to 

 readers of the A'jrirnltiu-nl Naws. Meanwhile, further results 

 obtained from continuation of the work already begun, 

 especially the cacao spraying experiments, will be awaited 

 with interest. 



SUITABLE MANURES FOR MAIZE. 



The Bureau of Soils of the United States Depart- 

 ment of Agriculture has just issued Bulletin Q-i, entitled 

 Fertilizers for Corn Snils, in which the following 

 summary of conclusions in regard to the subject is 

 given : — 



The ex[ieriment stations have reported the lesults of 

 6,391 tests with fertilizers on corn soils. 



Duplicate control plots show such variation.?, and the 

 range of crop increases due to fertilizers is so wide, that 

 considerable latitude must be allowed in the interpretation 

 of all results, and quantitative conipari.sons should not be 

 given too great weight. 



The chances for increa.sed yields, and the actual increases, 

 are greater with two or three materi^ils mixed, than with 

 single fertilizers. 



Increasing the aiudunt of any single fertilizer from 1 to 

 10 times does not appear to have any significant effect upon 

 the increased yield obtained from the smaller amounts, applied 

 within the limits of the experiments. 



From the records, fertilizers appear to have yielded, on 

 the average, about the .'^ame increase in the crop on the more 

 productive and on the less [iroductive soils. 



In the great majority of cases, and on the average, the 

 increase of product due to the use of fertilizers on corn soils 

 does not appear to be equal to the cost of the fertilizers ased 

 to produce the increase. The average cost of the fertilizers 

 used in all experiments was $7-06 per acre, the average 

 increase in crop was 9-2 bushels of shelled corn worth, at 60 

 cents per bushel, .■?") .52 indicating a net average loss of 

 si -42 per acre. 



It would appear that much yet remains to be determined 

 as to how fertilizers act, before a ration il and economical 

 fertilizer practice can be worked out. 



As these results have been obtained from a large 

 number of .^oils, with a considerable range of productivity, 

 over a number of years, these general conclusions, besides 

 others of a qualitative value which can be drawn froiu the 

 tables, can, in the absence of any more specific knowledge of 

 any particidar soil, be safely followed as a guide to the 

 immediate selection of fertilizers for a corn soil. 



