106 



THE AGRICULTURAL NEWS. 



April 5, 1919. 



INSECT NOTES. 



THE CONNEXION OF SKIN DISEASES IN 

 CATTLE WITH TICKS. 



In the IVest Indian Bulletin, Vol. XV, p. 36, there 

 appeared a paper on Skin Diseases of Cattle in Antigua, by 

 Mr. P. T. Saunders, M.R.C.V.S., formerly Veterinary Officer 

 to the Imperial Department of Agriculture for the West 

 Indies. This disease was supposedly identical with a disease 

 of cattle which eiisted also in Guadeloupe, and was known 

 there z& farcin de boeuf. 



In Guadeloupe the disease was said to aft'ect horses and 

 mules as well as cattle, whereas in Antigua Mr. Saunders 

 found it confined to cattle only. The disease was considered 

 by Mr. .Saunders to be probably due to fungus infection 

 through wounds in the skin, and that the lesions following 

 the punctures of the 'Gold tick' {Atnblyomma variegatum, F.) 

 were the principal seat.s of infection, although other wounds 

 caused by thorns, barbed wire, and other means ought also 

 to be taken into account. 



Mr. Nowell, the Mycologist on the staff of the Imperial 

 Department of Agriculture, reported after investigation of the 

 matter contained in such wounds, that at least two of the 

 various fungoid organisms which he found therein might be 

 likely to be the cause of a skin disease. 



The diagnosis of this disease, and its connexion with the 

 punctures of the skin effected by Amblyomma, which were 

 put forward by Mr. Sauntlers, tend to be confirmed in a paper 

 by Mr. E. M. Jarvis, which was published in the Vttennary 

 Journal, February 1918, on Ixiodic Lymphangitis during the 

 German Ea-st Africa Campaign, 191617. A summary of 

 this paper, which appeared in the tievie'M nf Applied Ento- 

 mology, .January 1919, is given below. 



The paper describes a number of conditions due to the 

 secondary infection of wounds caused by the bites of ticks in 

 horses, mules, asses, and more rarely cattle and sheep The 

 micro-organisms concerned include the Preis Nocard bacillus 

 (Cryptococcus Jarciminoius) occasionally, the necrosis bacillus, 

 staphylococci, etc. In Southern Rhodesia the disease was 

 almost entirely spread and mechanically conveyed by a tick, 

 Amblyomma variegatum, but it seems to have disappeared 

 from there since? tick eradication was efifected. It is stated 

 that an examination of over 1,000 cases in 'German' East 

 Africa showed that 75 per cent, contracted the disease through 

 the agency of Amblyomma and 20 per cent through the agency 

 of Stomoxys. The remaining :> percent, were directly inoculated 

 through the entry of organisms by abrasions from thorns, etc. 

 That this one genus of ticks should be so pernicious, is due to 

 the length of the rostrum, to the habit of keeping the rostrum 

 pendulous, and so scooping up the vims off contaminated 

 ground, to the polyandions habit aggravating the lesion, and 

 to the considerable longtvity of the lick, atfotding it an 

 opportunity of leaving an infected host, and attaching itself 

 to another. .Stomoxys and Tabanids have been observed to 

 infect unabraded tissue by direct inoculation, and tick birds 

 Miay be mechanical carrier?, as they peck at open wounds. 



and go from one animal to another. As regards prophy- 

 laxis, the author found in Southern Rhodesia that if ticks 

 were pulled off within twelve hours no infection resulted, as the 

 rostrum had not penetrated to the sub-connective tissue. In the 

 East Africa campaign this measure proved fairly successful 

 in the 4th S. A. florse on the march. Even up to twenty four 

 hours the disease could be prevented by pulling the ticks off 

 (rostrum aud all), squeezing the minute sinus which exudes a 

 serous discharge, and painting with iodised phenol 0:4). 

 This method was eminently successful in South Africa, and 

 all the B.S.A. police were supplied with a small bottle and 

 brush, and not one case occurred in the force after its p.-actical 

 application. It could not be employed during this campaign 

 as drugs were unobtainable. Under peace conditions, tick 

 eradication, the destruction of flies and of refuse, and th«) 

 segregation of malignantly infected wounds may be adopted, 

 but this policy would require a few years. 



It may be noted that the skin disease of cattle is attract- 

 ing much less notice in Antigua at present, probably owing to 

 the fact that more attention is being paid to tick control 

 and eradication by means of sprays and dips, and that these 

 are proving efficient. 



SISAL AND HENEQUEN. 



The two fibre plants, to the cultivation of which atten- 

 tion is being seriously directed in some islands of the West 

 Indies, are Sisal {Agave sisa/ana), and Henequen (Agave 

 foiircroydes). There is a considerable area at present in 

 Jamaica under these plants, and very valuable notes on the 

 cultivation of them are contributed by Mr. William Harris, 

 F.L.S., Government Botanist and Superintendent of Public 

 Gardens, to \ht Jour nil of the Jamaica Agricultural Society, 

 February 1919, most of which is reproduced below. As 

 Mr. Harris says, much probably has to be learnt to secure 

 the best results under local conditions. It is not advisable 

 blindly to follow methods that are adopted in other countries 

 where possibly very different conditions obtain: exact know- 

 ledge can only be gained by experience. These notes appear 

 to be compiled after considerable experience in the cultiva- 

 tion of the plants in Jamaica, and will probably be found 

 useful to intending sisal growers in other of the West Indies. 



Sisal {Agave sisalana) is more widely distributed than 

 any other fibre-producing agave. Although it is a native of 

 Central .\merica and Mexico, it is not there cultivated for 

 producing fibre for export. Henequen {Agive fourcrovdes), 

 also a native of .Mexico, is the species cultivated in Yucatan 

 for the production of fibre for export; aud in the markets of 

 .A.mefica and Europe this fibre is usually also called sisal. In 

 fact it constitutes more than 90 per cent, of the sisal fibre of 

 commerce. 



The leaves of the si.sal plant are dark green or slightly 

 glaucous, each 3 to 4i feet long and 3 to i\ inches wide at 

 the middle: each plant produces about forty to sixty of these 

 leaves at a time. They are furnished with a slender dark- 

 brown terminal spine, about 1 inch long, and usually there are 

 no spines .along the margins of the leaves, although occasionally 

 they are furnished .sparsely with small out;ward-pointing spines. 

 The leaves of the honequen are produced on a trunk often 4 to 

 6 feet high; they are 80 to 100 per number per plant, and 

 from 4 1 to .5 feet long and 4 to 6 inches wide at the middle 

 of a light bluish-green colour. Unlike sisal, the henequen 

 produces uniformly blackish spines straight or gently 

 curved upwards, along the margins of the leaves. Both of 

 these species prrjduce a flower stalk or pole froin 12 to 25 



