

THE AGRICULTURAL NEWS. 



June 1'.', 1915. 



FUNGUS NOTES. 



THE CAUSE OF CITRUS CANKER. 



In I i volumi u ji lurnal, on pages 1 I. l ,; . 



< n ker, 



a new and extri I disease I is trees, 



..pi- fruit, which has appeared in the United 



II E. > n 124 of the Florida 



Experin - iie disease to a fungus of the 



Phoma : b h of two infecl ions 



ol negative results, by spraj 

 with i pure cultui 



In the J mil R ed by the 



U.S. Department of Agriculture, Vol. IV. No. I. dated April 

 1 5, 1 9 1 5, ap| pi • report on the subje< I ■ J 



Citru canker, bj Clara II. Hasse, Scientific Assistant in the 

 Bun a oi Planl [ndusl rj The author has isolated a bac 

 tri i . . in, b bich • ■ wnas citri, which 



is cl ! unimpi achable evidence, to 



be i hi 



'I'h. Following paragraphs are quoted from the report in 

 questi >n 



'Tin- inoculations were made on young, healthy, vigor- 

 |j growing grapefruit seedlings, which were kept in the 

 laboratory because the highly infectious nature of the 

 ease made it impos my mi the experiments in 



the Department green houses, Pure cultures ol the organism 

 were mixed with sterile distilled water, and the suspension 

 thus obtained was placed upon the upper and under leaf 

 surfaces by means of a sterile pipette in such a mannei that 

 the leaves were, for a short time al least, covered with a film 

 of the inoculating fluid. The main stem and branches were 

 treated in the same way. In some- cases the leaves and 

 stems were punctured with a sterile needle, but this is not 

 necessary, as infections may be obtained without thi- 

 procedure. As soon as the plants were inoculated they were 

 placed under bell jars and kept at a temperature of about 

 86 1-'. Under these conditions the organise i rigorous 



hold mi its host, and in three or four days evidences of 

 infection can be noted. At the end of a week definite, well 

 defined cankers which penetrate the tissue of the leaf have 

 been formed. Owing to the stimulating influence which the 

 organism has upon the infected leaf tissue, then- is a rapid 

 development of cells, and the tension resulting from the 

 abnormal growth quickly ruptures the epidermis and exposes 

 the soft, spongy, underlying canker tissue, which is distinctly 

 visible on both sides ol the leaf. The cankers produced by 

 artificial inoculation pp i i haracteristic appearance, and 

 closely resemble natural cankers in macroscopic as well as in 

 in- 1 1 . ii ipic itu They ] el rate the tissue of the leal 



and are more or less raised on both the uppei md lowei 



surfaces. Tl tline is circular, and there i- a sharp, 



disl incl - n the canker and th ding 



normal li it tissue. \ oun^ i ha vi a sofl spongj 



structure and at first -how a light-green colour, which I 

 turns r d-brown. The cells in ei tissue become 



Buberized and | tu< e a a n kj growth, whi i ... 



of the 'I ea Thi open, sp - anker is the 



' h due to favour..' . of 



temp i i ire. 



'While the canker is still soft and young, th organism 

 i- in a very active lily. 



Upoi out a small pii w ol in a drop 



reat numl 

 lilky, turbid appeal it ilitj of 



the organism can be most satisfactory observed by means 

 of a dark lield illumination. The organism was re-isolated 

 from thus,- cankers by plating oul on bee! agar, md was 

 found to be identical with the original organism, [nocula 

 tions on grape fruit plants with the organism obtained from 

 this re isolation produce characti ristic cankers. 



'The open surface of the can] he sp mgj character 



of its structun excellent lodging place for spores 



of all sorts, and it is not surprising to find fungi, some oi 

 which may perhaps play a minor pari in thi 

 the disease. A number of fun ed from old 



Citrus cankers, and a study of their relation to the canker 

 problem shows that the fungus flora of the Citrus canker 

 perhaps ma) bean interesting problem in itself.' 



AGRICULTURAL AFFAIRS IN ST. KITTS. 



A large and representative meeting of the St. Kitts 

 Agricultural and Commercial Society was held on Tuesday, 

 May 18, 1915, to iii. Mi Dr. Francis Watts. C.M.G., 

 Commissioner of Agriculture for the West Indies. His 

 Honour the Administrator presided at the invitation of the 

 Vice-Chairraan of the Society, and introduced Dr. Watts to 



the tting, paying a high tribute to the work of the 



Imperial Department in these islands. 



Dr. Watts, on rising, explained the functions of the 

 Imperial Department of Agriculture. By means of the 

 valuable literature and information that passed through their 

 hands they wire able to supply information on mosl 

 agricultural matters. The Commissioner pointed out that 

 agricultural societies were a useful means of disseminating 

 information, and other function- of such societies were also 

 briefly referred to. 



The subject of Cotton was then dealt with, more 

 especially in connexion with the guarantee from the Fine 

 Spinners of a minimum [nice for fixed types of cotton during 

 the season 1915-16. Dr. Watts pointed out the interest the 

 British Cotton Growing Association had taken in this matter, 

 and thought that it was entirely due to their action that 

 this minimum price had been guaranteed. Types of cotton 

 had been fixed, and in the telegram received, St Kitts and 

 St. Vincent had been referred to as a standard at I8d. per lb., 

 and other islands at I id; but it was his opinion that these 

 standards would be according to fixed types of cotton, so that 

 it would be possible for cotton from any island to secure the 

 higher price if it was up to standard. 



Dr. Watts carefully pointed oul the distinction that 

 existed between the British Cotton Growing Association and 



the Fine Spinners, the latter being the sole purchasers of our 



cotton, and a large wealthy combine. The British Cotton 

 ( Irowing Association purchased no cotton and, as in this case, 

 protected the interests of the cotton grower. Extracts from 

 correspondence were read bj Dr. Watts illustrating this. 



St. Kit i s -tan. lard of cotton was due to soil and climate, 



but the Commissioner strongly advisi ! tionof 



seed so as to keep up til)e high quality of the lint. The besl 



safeguard in the Wesl Indies was the insular position which 



id tbarriet ii feci ion from outside - .hot-. 



lb- was issured thai then- would be a greal demand in 

 the near future for West Indian cotton. 



Turning to the Sugar Industry, Dr. Watts remarked on 



the presenl flourishing idition, the war having been 



for a rise in prices. He compared the prices 

 i with those of this year, and pointed oul there 

 was little # need for anj depression with sugar at these prices 

 and cotton at a guaranteed [nice of 18rf. per ft). 



