Vol. XL No. 261. 



THE AGRICULTURAL NEWS. 



U3 



ing, ribbing and folding of the heart leaf, provided no fruit 

 is present. The older leaves break off at the junction of the 

 stalk and the leaf sheath, turn yellow, and die in a few days. 

 The plants are quite dead a few weeks later. When fruit is 

 present, the stem remains with the bunch at the top, but 

 the fruit is without value, as even when it is apparently ripe it 

 has no taste. The root systems of diseased bananas do not 

 appear to be less strong than those of healthy plants. 



On cutting open a diseased bulb it is seen that the 

 vascular bundles are discoloured brown and that the dis- 

 coloration extends into some of the bundles of the leaf sheath 

 as well as, in some cases, into certain of the vascular strands 

 of the roots. The central portion of the bulb may commence 

 to rot when the disease is in an advanced condition, but the 

 outside remains firm for some time. The main differences 

 between this description and that of Levy are that there are 

 no external symptoms of disease in the roots, that the plants 

 dry up and do not rot, and that there is no smell The 

 absence of rotting in the bulb is a particularly noticeable 

 point of difference, except in the final stages of the disease. 



Drost has shown by infection experiments that the 

 Surinam Panama disease is due to a fungus named Leptoipora 

 musae which has Cephalosporium and Fusarium stages in its 

 life-history. It can penetrate the root hairs, and thence 

 spread into the central bundle of the roots, whence it passes 

 into the root stock and ascends the vascular bundles of the 

 leaf sheaths. Usually, however, it attacks directly the bundles 

 exposed at the place where the suckers have been cut from 

 the mother plant, under the surface of the soil. The fungus 

 is not as a rule found in the leaf blade or in the fruit stalk. 



It would seem, from a consideration of the literature 

 cited, that the disease described by Earle from Stony Hill, 

 Jamaica, has probably no connexion with the other forms 

 described, and is purely a leaf disease. This opinion is sup- 

 ported by some remarks made by Cousins, and published in the 

 Jamaica Gleaner for .January 19, 1912, in which he states 

 that the plants in that locality did not show any indications 

 of bacterial disease of the roots, but clear evidence of a fun- 

 gus disease of the leaves. Apart from this, there are two 

 fully described diseases affecting the vascular bundles, and 

 therefore the water-supply, of certain varieties of plantains 

 and bananas. The first is the Moko disease described from 

 Trinidad, due to Bacillus musae, occurring on certain varieties 

 of plantains and bananas, but not usually on the Gros Michel. 

 The second is the Surinam Panama disease, due to Le/Jtosjiora 

 musae, and attaining its greatest virulence on the Gros Michel. 

 Further, there seems to be a reasonable possibility that the 

 incompletely described forms of Panama disease mentioned 

 as occurring in Trinidad and Cuba will prove, on more com- 

 plete investigation, to be identical with that in Surinam; 

 while the similarity of the description of the disease in Bengal 

 with that of the latter cannot escape attention. It seems 

 advisable to regard the true Panama disease of Central 

 America as distinct from any of the above, at any rate until 

 it has been further investigated It may be that the noted 

 differences in symptoms between this and the Surinam Panama 

 disease are occasioned by secondary parasites, probably bac- 

 teria, which develop in the tissues damaged by the primary 

 agent, and that this primary agent is the same in both cases. 

 This, however, is purely a speculation. 



All these diseases are characterized by a destruction of 

 the vascular bundles which results in tne death of the 

 aerial portions, owing to the failure of the water-supply. At 

 the same time, the discoloration of the diseased bundles is 

 very similar in all the cases. This being so, it is natural 

 that there is some difficulty in determining the exact identity 



of any given disease by mere examination of the field symp- 

 toms, unless the inve.stigator is well acquainted with the 

 various forms, and with the minor differences by which they 

 may be distinguished. It is conceivable that, at certain 

 stages in the progress of the infection, even an experienced 

 observer might be mistaken; and, in any event, the isolation 

 and identification of the organism responsible for the disease 

 furnish by far the most satisfactory, and perhaps the only 

 definite, method of distinguishing them. 



Previous articles on the subject of banana diseases have 

 appeared in the Ayricultural Xews,\o\. X, pp. 110 and "2.54; 

 the latter deals more particularly with the work of Rorer 

 and Kssed, to which reference has been made above. 



PAINTING METAL PLANT LABELS, 



The following note on this matter has been received 

 from Mr. J. C. Moore, Agricultural Superintendent, 

 St. Lucia; — 



White metal plant labels, having the names formed in 

 raised black- faced type, are in common use throughout the 

 West Indian botanical gardens, and they are undoubtedly 

 the best form of permanent legible label for public gardens, 

 particularly in the tropics. An occasional scouring, followed 

 by a coat of paint over the raised type, is all that is necessary 

 to keep them perfectly legible. To paint over the raised type 

 without painting the white-metal body of the label may at 

 first appear a tedious and somewhat costly undertaking, when 

 several hundred labels have to be dealt with, but I have 

 devised a simple and expeditious method, which has proved to 

 be so successful that I think it is worth describing, in case it 

 may be found useful for trial in other public gardens. 



All that is required is paint well mixed to the consis- 

 tency of printers" ink, a slate such as is used in schools, or 

 some smooth, flat surface on which to spread the paint, and 

 a small rubber roller (I have employed a small roller intended 

 for use in connexion with photographic prints). 



A small quantity of the paint (about a teaspoonful) is 

 poured on the slate and rolled out into an even film. Pass- 

 ing the roller along the slate coats it with paint, and it is 

 then carefully rolled over the raised letters once or twice. 

 With a little practice, from forty to sixty labels can be 

 renovated in an hour. 



A table is contained in Bulletin No. 234 of the Bureau 

 of Plant Industry of the United States Department of Agri- 

 culture, just issued under the title The Cultivation and 

 Manufacture of Tea in the United States, which shows that 

 the quantity of tea imported into that country was, in 1 908, 

 94,149,564 ft, having an import value of .$16,309,870. 

 ( )f this weight, about 27 million pounds came from China, 

 47 million from Japan, and 20 million pounds from India 

 and Ceylon It is stated in the Bulletin that, although the 

 two last-named countries are increasing their trade in tea, in 

 the United States, the Chinese and Japanese teas remain in 

 the lead, perhaps because of the demand for green and oolong 

 teas. It is further considered that black teas are constantly 

 becoming more popular in the United States, and that they 

 may in time supplant the green tea, as has been the case in 

 Great Britain. 



