The Farm. (Extracts from New Zealand Farmer, Bee, and Poultry Journal.) Management of Silkworms.

Te Aroha News, Volume IV, Issue 197, 2 April 1887, Page 2

The Farm. (Extracts from New Zealand Farmer, Bee, and Poultry Journal.) Management of Silkworms.

In our last we gave an extract from Mr Schoch's pamphlet on Silk Culture, which described the various stages and treatment of the silkworm up to the spinning of the cocoon, from which point we continue the extract as follows : Cocoon. — The cocoon consists of an outer lining of loose, woolly silk called "{lotssilk," and an inner pait, " the pod," which should be strong and compact, composed of a iirm continuous thread. This is the part u?ed for iceling, and upon its consistency (quantity of silk) and the fineness and gloss of its texture depends the commercial value of the cocoon. The Chrytalis requires no special description. It makes excellent manure. The chrysalis state lasts tvom twelve to twenty days, when the skin bursts, and the moth emerges. After about eight days from the time spinning commenced the cocoons may bo gathered, and aie now leady for the market. Wheru reeling establishments aie at hand the cocoons may be delivered at once, after tho floss silk has been taken oif. lv New Zealand (theie bung no filatures as yet) it wih be better to choke the chr^sali^ and dry the cocoons. Their weight .ull decrease about GO per cent., but their price will increase in exact piopoilion that is, 31b. become lib. ; but it is the chrysaluwl.ich dnot> and causes the decrease of weight, ai.d no" the silk. Cocoons wi<h the grubs due< l tiro called " dry cocoon*," the others " f nth cocoons. 1 ' Some people having hand reels might choose to 10 d their cocoons. To the-e I would recommend not to leel only one cocoon afc a time, as such ?^lk us not maiketablc. Kaw frilU coiw-ts of the threads of fiom thiui to -ix cocoon^ combined in one, ac^o.ding to tho diflerent si/os required in tho nuv. ket. Italian and French reelera h.ivo acquir.nl perfection, and we canno. compete, tui vaiiou.-* reason.^. Bur pcison^ reeling fur amuMiiwut might make excellent fashing-lines ('hoKnuj (he Chi'tfaahx — All cocoons which are not intended for 10 pioduction (about which lutei on) must undergo the pioces^ of ht\ing the giubs killed, otherwise all tho moths would in coui&e of time woik their way out of the cocoons Such cocoon.^ — pierced cocoons -cannot be leeled, but have to be carded like cotton or wool They a\e of ittle value. Cocoons niav be choked by dry heat or by Steami-.g. Put them in an oven with a tempei.it me of about loO° Fahr. Two hours will i-ulhce By this method the .-ilk is often binned, if not caroiully lookei after. Where facilities are at hand steam ing is by tar the better and surer method. Put the cocoons in a tightly-fitting box, make a hole, and turn the Pteam in. Halt an hour wi.l do it. For sm ill quantities it is recommended to put them in shallow basket* or boxes and expo&e them to the rays of the mvi for two or three days ; cover w ith glass panes, and leave a small opening ior moisture to evaporate Cessation of a ceuain humming noise is an indication of the chrysalis being dead ; but the surest way of ascertaining the fact is again to cut a few cocoons and examine the chrysalis by pnckii.g it with a pin. This operation completed, the cocoons «.r e nnt j^cr-iiu on shelves, not more than '. i*. dl*^ *** M% to fc?. fbmtj &*& yhould be admitted, and the cocoons frequently stined. After this they may be kept for any length of time, but they a- c still liable to attacks from rats and mice. Selecting Cocoons for Reproduction.— Those people who intend to raise silkwoi m eggs for the next season will have to make provision accordingly. When the cocoons are taken from tho bush the largest and firmest should be selected for breeding pmpone*. Double cocoons must not be used. They aie recognizable by theii extraordinary size and unusual shape. Soiled cocoons, if large and iirm, may be used. Take, say, fifty cocoons, half males, half females (more or les«), which will produce about ten thousand eggs. _ Male cocoons are, as a rule, constricted in the middle ; female cocoons are not, but more round, and rather larger. However, it ie not always safe to go by this rule. A safei method seems the following, recommended by Riley : Weigh a hundred cocoons, and strike the average : all above the average tvill be found to be iemales. Paste these selected cocoons on paper or cloth, and in from twelve to twenty days the moth will Have worked itself out of the cocoon, The Moth.— The fourth and last state of the silkworm. The moth emits a strong fluid, which moistens the end of the cocoon, and dissolves the gummy lining, Then the jpoth emerges. The moth is of cream colour, Neither sex flies, but the male* flutter continually with their "wings'. Females have larger bodies than males They ipoiie mostly early in the morning, and couple soon afterwards. Egg laying, or Reproduction.— Keep the room dark. If necessary, place sexes together Destroy all that are deformed. Should more males issue the first day than females, keep them in a box until the next day, when the reverse may be tho ' case. Strong males may be used twice They Bhould i amain together six to eight hours. If not uncoupled after twelve hours, separate them. Handle them gently, by fetting hold of their wings and bringing eir heads together. The males may be thrown away when all the females have been impregnated. Put the females on blotting-paper first, where they will discharge a yellowish fluid. From there put them on woollen or linen stuff or paper (in & slightly-slanting position, where the moth will lay her eggs (300 to 400). They are laid very regularly, as the moth very ■eldom leaves the spot. After two days the moth is removed, as all eggs worth having will be laid by that time. \ Let the eggs dry, and after a week they may be stored ay/ay in a cool, dry place until the following season. They are best kept on tho cloths they were laid upon. When deposited the eggs are yellow, and this colour they retain if unimpregnated ; otherwise they assume a darker colour, and become indented. The female moths may be thrown away also. In Italy and France the female moths are kept for the purpose of microscopical so as to ascertain whether tho eggs are healthy or not. Silk culture is in its infancy yet in New Zealand, and I am not aware of a^ diseases having shown themselves in the few cases where people have raised silkworm eggs. I refrain, therefore, from givi*ig a description of those terrible diseases which made their first appearance in Europe about twenty years ago, and nearly ruined the industry, put which, thanks, chiefly, to the researches Of Paateur, were successfully combated I trust I shall never have occasion to refer to them as existing in New Zealand. From the facts and figures given on the page of the manual we gather the Uowing information :— , The iisue of one ounce of silkworm egg is £0,000 wgrmi. The proper temperature at

which the worms should be kept is from the fifs"t~to*~£rtlf clay after hatefiing 75 5 To"80* Fahr. From the seventh to the twenty -third day when the fourth moult occurs the temperature should be 72* to 75°, and after that 75°. Cleaning :- After first moult; between second and third moult, once ox' twice ; between third and fourth moult, twice j after fourth moult, three or four times. Professor Riloy gives the following figure-* as to food and space required for the produce of one ounce of eggs :—: —

These figures are based on practical experience in Italy and the United States. Raisers will, however, do well to be guided by their own common sense and observa tions as to renewal of food and increase of accommodation. Average number of eggs per ounce, 37,000 to 40,000 ; average number of fresh cocoons per lb., 300 to 400; maximum amount of fresh cocoons from loz of eggs, 1501b ; average amount of fresh cocoons from loz. of eggs, 801b. to 1001b. Two adults can easily take charge of 20z., or 80,000 worms. 31b to 3^lb. of fresh cocoons equal to lib. dry cocoons. One moth lays three to four hundred eggs. 3Jlb. to 4lb. of dry cocoons make lib. raw silk. 101b. to 121b. of fresh cocoons make lib raw silk. Length of thread from one cocoon, 800 to 1,500 yards, according to breed.

First nge Second age rinrd ago Fourth uge Fifth age Food. "., Sib. .. 2ilb. .. Gslb. ... 2001b. .. 1,2001b. Space. 10 so 50-75 100-100 /320 U3O-W0 squaro feet » ii