Account of the Black Canker Caterpillar, Which Destroys the Turnips in Norfolk. By WilliamMarshall, Esq. in a Letter to Charles Morton, M. D. F. R. S.Author(s): William MarshallSource: Philosophical Transactions of the Royal Society of London, Vol. 73 (1783), pp. 217-222Published by: The Royal SocietyStable URL: http://www.jstor.org/stable/106488 .

Accessed: 24/06/2014 23:55

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.

.

The Royal Society is collaborating with JSTOR to digitize, preserve and extend access to PhilosophicalTransactions of the Royal Society of London.

http://www.jstor.org

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

t XI7 1

SIII. Stto8Xt yf hc Black Canker CaterpiLIars wbich deJ!rfiys

the fis gn Norblk By ZWilliam MarShallb 0 4

Lc(fer to Charles Morton, M. DW F 1<. 50

1tead February SX X 783

s I t Gunton, near Avllham, Norholt

AuguR z2, 1 78x

A FEW months after you did me the honour of prefent

irlg my minutes of agriculture to the 13ritiJl MuSeumS I

came down into lKorfolks as agetlt to Sir HARBORD HA:KBORD.

To a perfon intelligent in matters of agriculture it would be

fuperfluous to fay, that Norfolk is celebrated for good huIlJarldz

zmen; or that- the turllip crop is the lJafis of the- Norfolk

lluSbandrye If a Norfolk farmer loSes llis crop of turnips his

;Srm is itljured fior feveral fucceeding years s for it is not only

the loEs of the imLmediate prolSt, which would otherwife have

ariren to him from his bullocks, dbutX fhis xIatld is deprilred of

the confequent-manure and tramplillg (eIteetned highly ltenew

:ficial to the lIght larlds of this county) on which his future

srops of corn are efl*entially depetldaXt

Among the nurnerous ellemies to wllich turnips are liables

none have proved more fatal here than the Black Canker (a

fipecies of Caterpillar) which in fome years have been fo nu

merous as to cut off the farmer's hopes ill a ftw days. Ill

other years, however, the damage has been littles and ill

others nothitig About twenty years ago the whole country

VoL LXS1IIt F f sva-

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

lI8 . MARSHAL:L'S ;s¢aN#! <

was Ilearly Aripped; and thls year it has lseen iHe&ed to a

rllllilar fite Many thOufalld$ of acreSX upon which a ilret protuea ir a crop of turilips 11aS not lleen reen ir many years

have lJeell plowed up; alld asX Eom tthe feafoll l)eing Ilow fEr 9?ellt) little profit Cat1 be expeEted Som a^feeQIld foRiTlg; tlle

lofs o -t>R> ClnzDrsS idivilually, vvsill be very confideralblet and tA ^

to t -e corlnty S¢ gti<;>tl e

It \V;ttS oL?irved s* the cankeryear aleave mentiotled thatfi prior to t}zzz appen.ran<*9> of the cxaterpillarsS great lluln&rs of yeltow fl;es svere feell 1Ou? among the turnip plants Xj and 1t was thell IUfpeAed, that the calder was t1Lac caterpillar Rate of the yellow fly ; and {ince ttlat tI;Xle it has been remarkect, that carkers have xegularly follosved the appearatlce d thefe flies From their more freqalently appeariljg on the iacoaR and Sorn the vaft qllalltiwties which have I lDelieveS at diSrert

times beetl ohfierued OI1 the beach waffied up w tfhe tlde, it has been a received opinon asnollg the flrmers7 that they are not 1lative3 o£ this countryX but come a:crofs the oceall ancl obirvatils this year grearly corrol)orar:e the idea* :F>ermen upotl the eaRern ccafi declares that they adtually faw thela arrive itl cloud-like flic,hts b atlsd from the teRilmony of matly,

it feems tv be all illdEi@t table fafts that they fir0£ macle their appearance otl the taReltl coaft; alldX moreonrerS thatoll their iRrll be*ng obDrved} t}lby lay UpOI) md tlear thoe cZS b tl-ick and fo latlguidS tt-lat theS migElt have beelbcolle&ed into heapS Xyirlg it ts £Xtds in fnne; places tvro inches thick. Frorn thence they proceeded into the coulltryt alld even at vlae diSlance of three or iur rxflles Som the: coa^R thg w7ere iiexl in multi- tudes relUvIlbling fwarms of beesX kbout terl days afFer the stlppealatwce of the fles, thwe young caterpillars wWre firfi ob irved ots the uIlir Iides of the leaves o£ the turnipsy and ia-

* IEveD

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

the Black Canker CaterpitharJ - z t: ben or eiglltSdays more tlle entire plants, except tIae Ilronger; fibres were eaten up,- A border under the hedg@ was regularly {j?ad until the body of the inclofure was filliShed; btlt this don:e, the border was Iboll llripped, and tlle gateway, and earea the roadshave been feen covered with caterpillars travellitlg in queR of a fEeffi fupply of turnips; for the gralqes alld indeed every- plant, except the turnip and the charlock (finapis art venfis) theyventirely negleh, and-even die at their roots, with- out attempting to fEed upon them This deRruEtion has not been coilfined withill a fiew miles of the eaIlerll coaR, but has reached, more or leIi, illtO the ve center of the county The tniSchief; however, in the weltern parts of Norfolks and even on the north coaR, has ;lJeen lefs getleral ;- but I am aSatd it may be faid with a great; deal of truth that one half of the: turnips irl tlle county have been cut o£ 13y this voracious animal

A circumItalsce fo diIkouraging to induIly, and iWtlrious to

the public at large, will, I flatter myfelg Sirs be thougllt aV Xfliciellt apology for my troubliiig you with a relatioll o-:f it> and for myvtaking the liberty of I*enditzg you a male and a fblnale fly alSo olle of the atlimals in its caterptllarS and one whicll is in its chry-falis fl:ate ir pur inEpeAiotlS hoping that the publ.tc may become acquainted wit}w the umeans of pre- venting ill iture £b great a calami. :

IJeSt the flies tnay become disfigured in travellings it mayfbVe prlldent to Idy, tllat- tlleir wings are iur: that tilelr altenlw are clubbecl and about onewthird: of the le-n8;th of thelr 1tif, each- being cotnpofed of :tlitle joints: namely, two nest tT;e

Ilead, alsove which tsro there is a joillt Somewhat long-er than the reR and above t-his lis more jointss fimilar to the two tet Iow,, tE1at near the point Qf the tail Qf the-imale thdre ls a

F f z black

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

;2§2O . M ARSH A L LSS XC¢a28! af

black beck ^twardly fi-inged with hair; but xvhich, opentlg longitudsnally5 appears to lJe the e;ad Qf a caIes £olltainlIlg a

delicate point or Ring (about olle-t^rentCFll of an illch ia

tength) which on a curSory viev; Si3pCAl-S tO be a fimple 1an

ceolated inIlru nentX with a Ilreng, lirle paITing; dtes5rtl the midw dleS and ferrated at sts edges; butX ta a blofier illfpeeCion aflct

by agitating st fErongly witll the poillt 0t' a needle it feparates <to three otleedged inRruments hatlgertike as to their geneu

ral formS with a fpiral line or wrinkle witlding fronl the lpoint

tQ: the baI4e reakitlg ten ar twelve revOlut;otasS wl1lch iing

paflilng over their edg;esy gives them fome appearance of being

ixrratedb

By the help of tlzetw inflrumentsX 1[ appreheadS the female

depoEts her eggs in the edge of the turnipmleaf (or fometxmes

perhaps, itl the nerves 0 ribs on the under XrEace of the

leaf) ; thus far I can fayX and I think with a conficlerable det

g;ree of cer-taitlty that havllg put iome freffi turtlip leaves z}to a glaEs contaillit}g fevea10 of the male and female flies? I pexcexYed

(by the means of a fimple magnifier) that cone of the femalesX

after examillirlg attentively the edge of the leaf; antl fillcling a part which appeared ta me to harre beetl bstten urliheathed her

niRrumellts infinuated them into the edge of the leaf; alld

having forced them aSitnder iSo a5 to opetl a pipe or chanIl>l between themX placed her pubes (the filtuatiotl caf which fron

.

repeated and almoR incelEant copulatiorls 1 had been able to aItcerF tain preciIclyv and to the lower part of xvhich thefe lnArtllnents

liem to be fixed) to the o;rificeX alld having temained a fes-

feconds in that poIlure deliberately drew out the inflrlllnetlts

(which the tranfiparency of the leaf helel agaiall a £Rreng light affbrded me an opportunity of feeing very plainly) arsd proe cceded to fearch for another convenicat place fc r her purpofe.

Tht

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

the B1ai Ctanker Caterpillare nE

The caterpillar ha$ twenty feet (fix of its lUgs flSebing d conZ fi-derable le-t:gth, the otfl}er iurt-tetl very Ihortzl- andiin its--fir fiage *Xs of -a;Jett bla£k,, finooth as to ta privatiolla of hair, but- caered with irlaumerable wrinkles. E4aving acqutxd its full fize, it fixes its hilder parts firmly to the leaf of a turnip, or atly c?ther fubIlance and lJreaking its outer coat or fough near the head, crais outn leaviag: the Rin fixed to the leai; k The unllder coat, which it now appears ln is of a bllle; or lead colour, atld the caterpillar is evidelltly diluilliiBed in its fi-zeO It1 every refpedc it is the fame anitnal as before, and cont-itlues to feed o1l the turrlips for fome days longer: it then elltirely leaves?

ofF eatitlgf and L,ecomes covered v0rith a dewty moiRure which feems to exfude from it in great abulldatlce, atad appearing to I)RY of a glutinous tlatureS retains any loofe or pliallt fulRance which happens to come inveontaA with it, and by this meatls alone feems to fform its chryIAliXs -coat; Orle t f-nd laid-up

n S ' 2 S- *

in the fold of a xwitheredR tumip ;;lexaf: (thatV which I have the horlour of itlclotingXyou) was,0;0;amo1lg-<0fx o6ersS formed by pUttiNg cotmTnoIl gardenXmou:ld toT themVwhHe;iby were in thq exfudatory ltate above fdei:Eribed:.

.

From the generic cha-raders of; the-fl)y<I cotz-clude it to 1Ze a Tenthredo of HILL; but wheti* that volumitlous author be i:ufIRciently accurate; or svhCher,; froii} lJeirlg az almoIt elltire firanger to natural hiRoWry, I may, or £nay-not,, fuffici-etltly underRand my bookg l muR beg leave to fulemit to your fupe rior ktlowledge of the fubJeEt.

.

I am endeavouring to exte2ld my obServatiotus on tIzeSe luCeEss and am maklng fotne experiments concertlitlg thems the reftz1t of which I {hould be extretnely happy in being permitted to commuxlicate to you; and it: tnay be propet to adtl here, that

I I tW1

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions

:Zz Xr5 MARSHALLS JC§z0XX g ac3

IE ihould tuot have taken; tlle lzberty - of trOublitag yon pretuaw turely with this lette-^ had I no;t luckily met with atl oppartut nity of procu3ring fiome live fties (wliich are now become very fcXarce) > alld I flatter nayEe15 lthey wil1 co:me to your hands sa as

perfiCEt Ilatee

I am with the greatell reEpe& &Gz

This content downloaded from 195.34.78.81 on Tue, 24 Jun 2014 23:55:44 PMAll use subject to JSTOR Terms and Conditions