Vol. V. No. 113. 



THE AGKICULTURAL NEWS. 



267 



DESTRUCTION OF RATS BY VIRUS. 



In view of the interesting experiments that have 

 "been carried out in the West Indies, by the Imperial 

 Department of Agriculture, in the use of virus for 

 destroying rats, the following note from the Journal of 

 the Board of Agrictdtitre (Great Britain) for June is 

 likely to be of interest : — 



During recent years rats appear to Lave become much 

 more numeious in most parts of the country, and the damage 

 they cause to crops, poultry, game, and even young trees is 

 undoubtedly very great. Until recently the usual means of 

 destruction consisted of traps, poison, and ferrets, but during 

 the past few years attention has been given to inoculation 

 with a virus, which sets up a virulent disease in the animals 

 and quickly kills them. There are several such preparations 

 before the public, some of which are fluid and some solid. 

 Perhaps, on the whole, the fluid preparations are the most con- 

 venient to use, and they are certainly quite as effective as the 

 others. The material consists of a nutrient medium containing 

 the organisms (bacilli), which, when introduced into the body 

 of a rat, set up a disease allied to -the most virulent form of 

 typhus fever. Dry bread, cut into small cubes, is soaked with 

 tfie virus, and these cubes being laid down in suitable places 

 are readily eaten by the rats, usually with fatal results. No 

 ■domestic animals are at all affected by the preparation. 



In order to test the value of the method, the Agricultural 

 Chamber of the province of Saxony obtained a supply of 

 one of the preparations and distributed it amongst seven 

 selected farms. The results show that at six of the farms 

 the rats were practically exterminated. At the seventh the 

 virus appears to have had little effect, a result that has also 

 been noticed elsewhere, and which is supposed to be due to 

 the fact that a natural attack of the same or a nearly-related 

 disease had rendered the surviving rats practically immune 

 to infection 



Information of a similar character has reached the 

 Board with regard to the use of rat virus in England, and 

 they would therefore direct the attention of agriculturi.sts 

 to this means of getting rid of a troublesome pest. While 

 there seems to be little doubt that, in the majority of cases, 

 a single farm may be temporarily cleared of rats by this 

 means, it is evident that but a short time may elapse before 

 such a farm is again invaded by animals that move on to it 

 from infested places in the neighbourhood. It would there- 

 fore appear to be highly desirable that agricultural clubs 

 should take the matter up and act on a large scale, or the 

 farmers in a parish or county might enter into a temporary 

 association for the purpose of using the virus on every farm 

 on a definite date. Operations on a large scale would mean 

 considerable attention as to organization, but the probable 

 result would appear to warrant the necessary steps being 

 taken. 



the crop matures in three months. Bending of the brush was 

 prevented by lopping or bending down the heads as they 

 pushed from the sheath. 



The brush was reaped at three different times, and after 

 cleaning off the seeds by a home-made comb, was dried under 

 cover. The yield from the plot was 63 Bb. of dried brush ; 

 this was at the rate of 5iO B). per acre. 



A shipment of a sample bale, weighing 56 fti., consisting 

 of 49 lb. of long brush and 7 lb. of small heads, was made to 

 Mr. J. llu.ssell Murray, of Montreal, Canada. His report on 

 the shi[>ment was as follows : — 



' I have thoroughly examined the broom corn, and beg 

 to report that it is of first quality in every respect. It is of 

 good colour and free from seeds. The sample of dwarf corn 

 accompanying it is fairly good. This corn can be marketed 

 in Montreal or any eastern seaport town at from 410. to 6c. 

 per lb. At present it is bringing 6c. This, of course, includes 

 freight and shipping charges. 



' Should this cultivation be increased, you would be able 

 to grow two crops per year, and there is no competition here, 

 as broom corn is not grown in Canada, and heavy rail charges 

 have to be met from the states of Ohio and Illinois. 



' I shall be pleased to take charge of any shipment you 

 can send me, and if you can assure buyers here of a steady 

 supply, they will make contracts for all you can produce.' 



In view of the above encouraging report, it yet remains 

 to be seen whether this crop can be hcindled with sufficient 

 skill to make it profitable. It does not seem probable that 

 a much higher yield of brush could be obtained per acre ; but 

 as two crops could be reaped from the same land in six 

 months, this would mean, at the price quoted, a gross return 

 of about £11 per acre. 



The chief items of expenditure, exclusive of preparing 

 land, manure (if any), and weeding, would be : — 



£ s. d. (Estimated) 



Lopping brush 2 per acre. 



Reaping b „ ,, 



Cleaning 10 „ „ 



10 „ „ 



This would mean for a single crop. 



On estates, where work is generally done by the task, 

 this expenditure would probably be much less. 



On a large scale it would be almost necessary to have 

 a machine to sow the seeds. 



BROOM CORN IN MONT3ERRAT. 



lu view of the efforts that are being made to 

 ■develop a small industry in broom corn in Montserrat, 

 the following extract from the Annual Report on the 

 Botanic Station for 1905-6 is likely to be of interest : — 



A second trial has been given to this croi>, and the 

 results show an improvement. The area under cultivation 

 was /ij acre. The land was spaded, and one half of the plot 

 manured at the rate of 36 tons per acre. 



Seeds were sown with the Planet Junior drill on October 

 12; one half of the plot 3 feet apart, and the other half Si- 

 feet between the rows. The cultivation is very simple, and 



DEPARTMENT NEWS. 

 The Imperial Commissioner of Agriculture is 

 expected to leave the United Kingdom on August 31 

 for Canada. 



Mr. Henry A. Ballon, M.Sc, Entomologist on the 

 staff of the Imperial Department of Agriculture, has 

 returned to the West Indies, having resumed the 

 duties of his office at St. Kitt's on August 18. As already- 

 stated in the Agricidtural News, Mr. Ballou will 

 spend some time investigating insect pests in the 

 Leeward Islands and in St. Lucia before returning to 

 Barbados. 



Mr. F. A Stockdale, B.A., Mycologist on the staff 

 of the Imperial Department of Agriculture, returned 

 to Barbados from Trinidad in the S.S. ' Ocamo ' on 

 Wednesday, August 15. 



