THE GRAIN MOTH.

Dominion, Volume 1, Issue 257, 23 July 1908, Page 3

THE GRAIN MOTH.

IS IT SERIOUS? SOMETHING. ABOUT I ITS HABITS. ! Tho arrival of mothy maizo at Auckland and the reports :that > have, been circulated ' about it hayo i caused a certain vague fear lost this now enemy battering our. shores for a: footing should add another to . the . farmers' many heavy burdens. They will like to' know -something about it. '■' - Oiir friend's Latin • name is sitotroga- corealella;. ,but to -modfernpractical ; farmers it 'will be' sufficient td call it the Ahgoumois grain' moth. / It won the name' of Angoiimois because of its conspicuous work in that French provinco on various occasions. Sitq T :. troga;; is-thought, to' be indigenous, to' Mediterranean regions; ." . ■/- ; How it Works. ' /: ! It is,: in.' its moth ' form, a minute ; long' shaped creamy grey creature. It lays its . -. eggs oji the /seeds," of grain crops as' they grow : in the fields or after .they .have been stored, and from. the: egg there hatches a . tiny- maggot. Tho; maggot immediately tun- : nols into, the' grain, ' closing up, the' entrance holebehind ;it :and settling': down.' in-,the . inside :i of the grain to a fife of ' ease- and abundance. It eats;-and eats .till''it has . made . the' grain quite' hollow.- Then,' with .. a- comfortable feeling of / satiation, it resolves to pupate. Hitherto it has'been a creamy white 'maggot j 1 but now: the: creami-' ness deepens. Wonderful Instinct! . .// But- before -it falls -into; itsvlong,'deep" . sleep it ■ has : one last act of prudenco to I , perform.:. It-idust cut an> exit, lest'it should . wake:-up-: on. the resurrection day an im-1 , prisone'd moth.! For now, while ; it is a'l - maggot, it 'p'ossiis'ses a, snout which,' in . its ' slow, persistent - way, can '.cut-/Slid;. worry and; tear and 'tuniiel -tho''substaricp' : of;.tho grain. \Vith: the .keenness of'a; chisel—a valu- / able instrument 'that will have, vanished when .;- it. has become a moth. -' So tho ' maggot , chooses" a spot'. on tho l inner surface of the, grain, and there' excavates till only a • thin film .separates it' from 'tho outer world—a film 1 so thin: that -a. push; from the-delicate . head :of ; a-: slender.- moth :by and ,byo can: burst through it. ' , • - ■ .'.. ■ What. a splendid exhibition of instinct i Who .can. tellwhat thoughts thrill'the mind ; of 1 this tiny, creature while he picks bo per- • sistently' at*..the: wall of: his cave', dwelling?: Does -he know, he ' will bo .a moth -later' on ? .Or.is he.simply obeying the dictates of some' mysterious impulse? ...It.is 110 mere accident,' this tremendous preparation. It .is as full of. motive as .the act'of/the-head; of a household in/seeing that all lights arc out, and fires safe, , and back doors , bolted , before retiring to bed at' liight.' . But how does tho little. creature"i'.know' when . the'. excavation has proceeded far enough! and tho film is thin enough for' a' moth's head to break through? Porhaps he caii see. Who knows? .Perhaps' the-frail instrument that is pick- ■ axe and shovel,, and mouth and teeth,; is also'.eyes, and ' can , soe tho faint flight' shining through as the, partition grows-thin-ner..- "" " The Sleep of! tho Chrysalis. Then ho cuddles himself; up in his cot, covers himself with a garment'' of silk, : and : sleeps. • He is a chrysalis. • And while he ; sleeps; .the wonderful : changes , peculiar to creatures -of his sort take place. His skin toughons and darkens and separates, itself from > the rest of l his body, 'leaving him cradled,'as it. \vera, 'in -his: own skin/-,' And : gradually there develop tho '• head of wings. " and lees aiid figure of a creamy 1 grey' moth, somewhat like the clothes moths,- for which careful housewives place carbon balls' - in their wardrobes. This change, if the weather bo'-,warm, may-take place in a few - weeks/ : Or,r- if' - : it; be later, autumn,-'; tho. 'sleep may .. continue, throughout tho- winter,' and ,the, / moth will - .iibt.' (toefge'/from -the ' grain till" . the "spfirig,'-/when'the/crop's . of-grain, kre .ready; for/him/.'/ He-.ha's a fine" long lirip of . "ancestors, comprising millions.of forefathers, for ho*'has two or'.three/orovon' eight' generations.- per annum. ." , ./ How the Eggs are Laid. . . If the egg, from ;which ho hatched was laid early.;in .the season he—or,':rather, she, for we have to change the ses : now—breaks through the thin partition, ; escapes , to tho open air, and-immediately proceeds to ,de-. posit; eggs :on..tho; growing-, grain: .-If/she has'.develdped'froriua-lato egg-she may.gain 'after- ; the !cr'op -is/stored .m/the granaries,. and .she .thon :lays -her .eggs upon 1 tho -.stored grain, so J that breeding and . destruction of .the ' grain go -on all' through the winter.-., / : . , • The 'eggs are deposited in groups of about' twenty,- at; a/.time.,;/ The/ inoth./seems / to' . know ,that : a' cluster of twenty, eggs'., is. a pretty;', fair supply to linfest. an' oar-of grain, and ' sho. proceeds .on to deposit another . twenty, on.'another' ear'.'. V '1 lie little maggots on hatching take a tour round, 'tho!, oar— their world—and then finally chooso each a grain that takes, their! fancy/and begin their, work. . . The female; moth lays , a .total of about- 80 , 0r..90 eggs, which hatch in . from four to seven days; -The moths continue their w ; ork in the mow, in the stack, and in the barns; so long as there is . any sound ' grain loft., j. . ''.. ■ '/ '-. '. Big Damage Possible. . : ' It will'be obvious that the little sitotroga ■is capable' of doing: a! lot; of damage in the course'oftwelw .months!;; 'It attacks wheat, mai?e>.oats, ; ! rye!/barley, sorghum;-and even cow peas.,' .. In " arid around vAngoumois (France), in 1760-"it .'became excessively abun- ',, dant,;: swarming' all' the' wheat: fields ■ and granaries; but it; had been- noticed as early as 1730. It. is now known, and feared in most; grain-producing countries of the world, and is . specially; active /in ■ North,-, America, the' Australian coast,:and the/South Sea Is- . lands. - •,- ,; . TIIO Cure. ■ i • Liko weevils and other insects injurious ; to . stored,grain,: it ,can/-bo ■ easily kept ■ in check by fumigation with carboir bisulphide, : which is a, cheap remedy,; satisfactory, in all ' ways. Prompt threshing, and, storing in moth-proof • bins or moth-proof sacks," are also deterrent. ./ The carbon bisulphide is used at the rato of from lib. to - 31h per 100. bushels .of , grain, or lib. for 250 cubic feet of , space.' ;. The bisulphide is put in a shallow-dish and placed ,on the grain in ,a closed space, such as a closed bin or/a-bin 'covered with..-canvas or.blankets. The bisulphido of /carbon . evaporates, and the vapour; . beingheavier!. than! air,';' sinks: ■ down through the'grain, killing air insects in : it within 24 or .48. hour's.

.The New- Zealand Government, however does riot intend'.to. let the invasion of sitotvoga reach this stage, and, as btated in The Dominion; .yesterday, legislation . to' prevent its entry into Now Zealand is under consideration. ■