RABBIT-POISONING WITH STRYCHNINE.

New Zealand Journal of Agriculture, Volume XXVIII, Issue 1, 21 January 1924, Page 32

RABBIT-POISONING WITH STRYCHNINE.

VARIOUS BAITS AND METHODS.

Live-stock Division.

(l.) CARROTS AS BAIT.

Poisoning in this form is very effective in winter, when the carrots are fresh and crisp. If carrots are allowed to become soft and dry, the rabbits do. not eat them so well. The methods adopted are . as follows :—• (a.) Strychnine and Sugar sprinkled. ' - ■ ■ Cut up 15 lb. of carrots into small cubes, add 1 lb. of icing-sugar, and drain off any liquid after sugar has dissolved. Lay the sweetened cubes in light plough-furrows or scrapes, two cubes every 4 yards apart. Feed in this manner for three nights, and if the rabbits eat the carrots proceed as follows : Cut up 12 lb. of clean carrots into small cubes, add 1 lb. .of icing-sugar, and allow carrots to drain until all surplus liquid runs off grind 1 oz. of strychnine into fine powder, and sprinkle a teaspoonful at a time over the carrots until the ounce is all mixed, stirring well after each application of strychnine ; then add 1 lb. of icing-sugar to cover taste of strychnine, and allow carrots to stand for two hours before laying. One poisoned cube every 3 yards is sufficient. (b.) Strychnine and Sugar Paste. Commence operations by free-feeding the rabbits for two nights in succession with unpoisoned carrots, laid 3 ft. to 4 ft. apart in plough-furrows, scrapes, or spade-chips freshly made. The advisability of liberal free-feeding for at least two nights is strongly recommended — in fact, it is practically essential to success. The baits in free-feeding should be similar to those which are poisoned, and should be laid in the same way. If the baits free from poison are well taken, lay the poisoned carrots on the third day. It has been found advisable to put out about four times the quantity of free-feed as compared with that poisoned. The poisoned baits should be laid from about 6 ft. to 9 ft. apart, according to the infested state of the land. The mode of preparing the poison is as follows: To 1 oz. of strychnine - crystals add 2 oz. of icing-sugar, '■ and after thoroughly mixing this add enough water to make a thick paste. -(Note that the strychnine-crystals will require to be powdered before adding the sugar.) ■ A 4 oz. bottle • with wide neck and glass stopper is most suitable for mixing the poison. When ready to commence laying, have the. carrots clean, not washed. Cut the carrot straight across the top with a clean knife, smear the top of the carrot with a little of the poisoned paste, and immediately commence slicing off the baits', so that each bait will have at least a smear of the poison. When all the smeared part is cut from the carrot again apply the paste as before. The baits should be thin, not more than |in. thick and about fin. across. Each bait only requires a very small portion of the paste-smear (poison).

It is preferable to lay . the poisoned baits in the afternoon, and if rain comes on and the result is spoiled in consequence, immediately relay when the weather is again fine. All stock should be removed before poisoning, and if any poisoned baits are left after two or. three days gather up and bury. Carrots should be of good quality and clean cut, not bruised. (c.) Method for Large Quantities. When large quantities are being dealt with the carrots may be cut into cubes by being placed in a strongly made box and chopped up with a spade, then put through a sieve to take out the larger pieces for rechopping. The method of mixing the chopped carrots and sugar (without strychnine) is to place alternate layers of carrots and sugar in the box, and thoroughly stir up and mix together. When the poisoned baits are being prepared, mixing is done in the same way, with the addition of a sprinkling of powdered strychnine on each layer of carrots and sugar, the whole being thoroughly mixed together before removing from the box, so that each piece of carrot may get its share of the strychnine. If this mixture is considered by the user to be too strong it can be weakened by the addition of a few pounds more carrots. Minced carrots are sometimes used instead of the chopped-up article, and where laid fresh, results have been found satisfactory. Note.—Apples and swede turnips have been successfully used in place of carrots in the foregoing methods. (2.) OATS AND MOLASSES AS BAIT. This method has proved very effective, satisfactory kills having been made, and it can be used at any season of the year. It has been tried when there was plenty of pasture, also when - feed was scarce, and in both instances results were good. The method is as follows — Boil 15 lb. of oats (Garton's preferred) with 2 lb. of molasses or treacle and sufficient water until the oats are soft, draining off any surplus liquid. The oats are then ready to lay for feeding purposes. Run light plough-furrows about 2 chains apart on the land where rabbits feed principally at night, and lay baits of a dessert-spoonful every 4 yards apart in the furrows. In country too rough for the plough lay the baits in scrapes or spade-chips. Continue this for three nights, and if the rabbits are then ; eating the sweetened oats well, proceed with the poison as follows : Weigh out 24 lb. of boiled oats treated as before mentioned; pour into a wide bath or tub; grind 1 oz. of strychnine into fine powder, and sprinkle a teaspoonful at a time over the oats, stirring well after each sprinkling until the strychnine is all mixed ; after which add 2 lb. of sugar to give a sweet coating, as the rabbits having been fed on sweetened oats it is advisable to cover the taste, of the strychnine. Allow the oats to stand for two hours before laying. In laying the poisoned oats one teaspoonful is sufficient every 4 or 5 yards. The furrows used for feeding purposes will also do for. the poison.

(3.) GENERAL POINTS. Special care should be taken that all utensils used in the preparation of the poison are perfectly cleaned, and personal cleanliness should be observed and the baits handled as little as possible. It is held by some that the addition of a small quantity of oil of aniseed to the poison immediately before laying is of advantage in attracting rabbits to the bait, and also in destroying all traces of human handling. The strychnine should be ground as fine as possible, no grittiness to be observable. As strychnine is highly poisonous, the hands require to be thoroughly washed after the poison has been handled.

STEEPING TURNIP-SEED IN TURPENTINE.

In connection with the method of steeping turnip-seed in turpentine before sowing, with the object of warding off attacks of the “turnipfly,” a question has been raised as to the effect of such steeping on the germination capacity of the seed. A series of experiments recently carried out at the Department's seed-testing station showed that turnip - seed suffered no diminution in germination after soaking for seven days at a temperature of 65° to 70° F. in pure turpentine. As about twelve hours’ steeping is the practice usually followed, a good margin of safety is thus indicated. After seven days the vitality of the seed in the test began to be affected, a loss of 5 per cent, to 10 per cent, in germination capacity resulting from steeping for fourteen days.

SPENT OXIDE AS A MANURIAL DRESSING.

Some criticism has been expressed of the following paragraph, published in the Journal for November last : “Spent oxide, which can often be had from gasworks for the cartage, is rich in sulphur, and also in nitrogenous compounds which when allowed to oxidize on the surface of pasture are transferred into useful nitrogenous fertilizers. The sulphur is also of value on some soils.” It is pointed out that spent oxide is used as a destroyer of vegetation, and that nothing will grow where it has been deposited ; further, that when lying in bulk its fumes are deleterious to any adjacent vegetation. Commenting on this criticism the Department’s Chemist states that the position of spent oxide is analogous to that of salt, which in large quantities is. an excellent weed-killer for paths, &c., and is often used as such, whereas in small quantities it makes an equally good top-dressing for many grasslands or for mangolds and other plants which crave for salt. The Department has used as much as 5 cwt. per acre of spent oxide on pasture with excellent results,. a 5-acre paddock having been top-dressed with it. Outside authorities can also be cited as to the fertilizing-value of this material. Care should be taken, however, not to leave it lying in heaps on ground where any growth is desired, nor to apply it heavily for fertilizing purposes.