QUESTION ANSWERED.

Dominion, Volume 1, Issue 161, 1 April 1908, Page 2

QUESTION ANSWERED.

POTATO SCAB. . ; "M.'A.K-: y'VvPalme'rsW.'. North,'..sSys that i there aro-hundreds of potato crops .in the .Manawatu district affected with. scab, and he;'desires'--instructibli3; for treating 'it. - We caiinot' do':; better,).than -quote tfvhat.'Mr.i T. W. , Kirk (biologist), says in Bulletin 7;— ,'. . .''-Potato" scab' is. now- one -of --tho- most iiig"; tho' potato' tub&r,; ' being-' found ;in ".'all of the; colony and in, all distridtsi- ,Its ; -attack' usually- -oomniehces .when the-tubers are quite young, and the skin .soft;" Rounded , scattered. rougn "patched '• are' found cn .the surfacoi."and.',-theso v i often; irtcrease'v.tovsueh; ; ah extent,that the'whole:tuber..may'-,become; covered, v and';in- bad 'eases tho potatoes' often beebmo. 'cracked,:,and 'their market value , greatly depreciated. The- quality -of tho - ' scabbed ' potato:' itself.-,; is/ riot- much -, im- . paired^, and'.they. are quite 'fit for: all,; cull? niry purposes. Tho:cause of the disoaM ia a 1 fungus only known : '.ih ■, the-, eonidia.l - form, ; and; called '• eospbr.a scabies.,;: The hypllae of . ; this fungus aro very small and dclicato,. giving .-rise' tol numerous small ov,oid spores. : If scabby potatoes',are.:used, for, seed without being properly .. .treated,; the; resulting .crop ; is certain ; to.: b'e..'diseased.'Th'b .'fungus 'can ; also livejfor'.several jrears' in -tho soil .without'. : .tfio'int-erve'ntioh.of .a crop.:';' Scabby ' potatoes can,'however,^be-ised.for. seed with perfect safety'if they: are immersed for twel- . hours in a solution consisting of one:., pint ; of' Rotnmcrcial formalin (equaj- 40 per cent. fprmaldchydoV.,- . with forty ; gallons; of. : w'atorr ; .The'' jiotatoes-' 1 aro then spread Out to; drji'i and ; areV'tlien ready for planting.' Great enre must7be taken not, to place any > of the. treated 'seed into'- fiags- which; have previously contained scabby ' Vsets". f r: Lali'd ■' in which scab is pm alent should not-,'.unless ' iiecKsafy ) '!.' : be'-tpla I hte^ , '\.'.yrith l rf»tiitoes;..''fbr several seasons. Bc<;ts and. carrots aro-also said t-o -l)G liable -to -this disease,: but urv.to : thp- present.'l .have not, seen' it:in New Zealand carrots, . though' several cases; of-, beets' s so attackod-have been- examined. Cereals may bo grown':, on.;.;infected 'land.. l v. ? v • "I gardens-fwhoro potatoes are grown an-> ritially. the ground should-',be-,sprinkled' witH ; sulphur. -.'-;Limo-. increases, -the -disease; > and; acid manurps..act-'as retarders.;-, .Thei .use.of formalin,is much to. be:preferred to corrosive; sublimate;) which, used' to be looked, lipon- as the standard remedy."