OndeJ·StCJIUOtf ./oun}(JI uj retCI'/JI(U!J Science 1/Jid Ani?ll(ll
lndu.<IJ'.If, rolume 7, .YumiJet 2, October, 19:)(j,
A New Fly Repelle nt and a Blowfly D ressing.
Prelim inary Report.
Hy Tl. ( J. MOKl\ I.(J. ~P..t ion of I 'nnt,;itolog·y, On den;t epoort.
J..;n:;uYONE \Y'ho i;; actluainted ,,·itlt the problem of ntYiasis in sheeJl anrl othel' animnls and also in man, realises the inq)()I'Ltlll't' of a s<ttisfad or_l-tl_,-repellent, and lllU('il 11orl; has heen 1lone, parti('ubrl.1·
by Bishopp anrl hi;; asso('iates in the (fnile1l ~la(ps, to find a ,;nitable substance.
]n a ;;ean,;h fm Hy J'P]Jellt>uh tlw aui.hor h<ts t-Xalnined some oih of conunon South African planb nnd 11·ishes i.o ree;onl iu i.his artide some preliminary work on onp Rueh oil, '' hi('h appear" to be a ve1·y effective blO\dly repellent, a11!l also to repoit on test:-; of certain chemi1~als which arP Yen · to.'\ie to nwggols and ,,·hich could be used in combination \\'itl1 a I'PpPllent for lhP trealnwnt of myiasis.
'1',\GJ·:T.ES ()IL ,1s .I F t,Y Bl,PJo.LLEYI'.
The planl 'l'o.t;rles 111iuuuo (popnlady btOII'Jl in South Afri<;a as " kh<t k i ln1sh ") is a I'UllliiiOJI w(wtl \1 ltieh is a (;<1use of I ro11hle
lTI maize and othPI' b 11<b in lllOSi paris of the ruion. )j g'I'0\1-~ 011
poor, <h Y ~oil to a l1eight of a fpw illl'hec; \Yhile. in morP faYotu·<illle circum~btnces, it lll<IY reaeh :1 hPig-ht of :;pyeu feel anti fiH~ main si.Pm hPaJ·~ [I nun1her of hr<tll!'ht'~, ertl'h <lPYelopillg· a t·lu~IPJ' of small.
pale yello11· Ho11·p,·~ <t t its tip. If I he plant is t·ut it <leYrlop,; new bran!'hes and us11<~lly forms a mo1·e dt>nsP growth than hf'fore. 'J'he flowe1·ing season is towarrls the end of summer an<l <hn·ing lhe winier the plants niP off.
This plant I'OIItains a stroug·ly-smelling vobtile oil, 01· rather a mixture of oils, in its lenYPS, flowers an<l SPPns. The oil (':Ill easily ht> ohtainerl l!~- siPam <listillat-ion anrl I Itt> :Yield of i ht> +lowering· plant is about 0·5 per rent. of thP totnl \\·eight .
• \ fe11· ~'ears ago it ll.<ts mainl·ninerl In· a CPrlain IHitPr in the
<laily prPss that this plant <·onbins :111 :tdiYP prin1·iple whi<·h wnR dl'PdiYP for h Pntnwnt :tgain .. d intPrl\:11 and P.'\lernal parac;it·es. 'J'hP preR<•ill ::tuthor made earpfnl IPsts 11·it.h thP clistillP<l oil and also with infu~ions a1Hl rleeod ions of thP 1Yl10le plant a_g·ain~t· inien1al parasiies Hltl'h ns Tlnemmu-ll'lts r·mJ/nl'tus anrl ot'her g·a~t.ro-intt>siinnl parasites of shPPp anrl, togt>ll1rr ,,·ith }Jr. Brclfonl of this Jnstitnte, testerl the :material against l'sornJites roJIIInJuJis oris and Jfrlopl11Jf)1l-' m·i·nus on sheep anrl ticks 011 cah-Ps. In all <·asPs tltP re-;ults were entirrly negative with the exr-t>ption of a slig-ht {lnthPlminthic effect in some L:ases.
419
A 1'\EW :FLY ltEl'.ELLJ.::\T AKIJ IJLOWI.•'LY J)ltESSISG.
In onler to test ihe fly repellent properties of the oil vanous experiments were made.
A. TESTS IIT I'JI TllEATEJJ BAIT.
1. The firsi test "·as made hy diYiding i he liYer of <1 slightly decomposed sheep can·ass into two equal parts a 11 d J>la(:ing each half into ::1 large, sltallo11· gb ss disl1. Specimen A was the uni reaiecl control; 10 <lrops of 'l'agt'les oil wei'E' dropped on difrereni parts of B and the oil soon sprenrl oYer the ''"hole surface of thr liYer. The bYo rlishes "·ere pbced in the hroken ~harle of trees 11·herP bl01dlie~
were plentiful. 'l\1·0 cla.vs lutf'J' Rpecimen A 11as attracting large numbers of flie~ anrl containe(l numerous eggs anrl young maggots, while
n
was st-ill quite h ee of HiP~, ep:),!:S ancl maggots and !he Sllle11 of the oil 11·as still quite strong.2. The sel:ond test 11·as nwde in a 11·av similar to the method usecl by Bishop[l and hi~ (·o-workl•rs. (fl;~s hraJ,er;-; of one li!rP C<lpaeity 11·ere liSe(] as l:On[ainers. Jnto e<lCh 11·as IJlaced lllOist Sand to a height of 0 Clll., and on this GO g-m. lin'r an(l GO g-m. intestine,.;
of a sliglJll_,. cl e('Ol11JlOsrrl sheep (·an· ass. 'l'he l1a it 11·n;; s pri 11 klr(l OYer with I r·.e. of the re}>Pllent tested, attempting· io spread the t!uirl as evenl.1· ns pos~ible OH'l' !he hail'. 'J.'lw beakers "·ere Jlla('ed G feet a par( mJCier a t'h~1 tch roof O]Jen on all si<les. 'J.\yo beakers II' ere preJla re<l for ea<:h reJ>ellent a nrl there ,,·ere three controls; they were so ::n·Jaug-erl as to get the best JIO'stble balance, taking- into account the eJTed of light and the possible influenre of one specilllen ou !he othe1·. 'J'he results tne g-iven in thr follO\Ying- table:-
Tagetc,; Oil.
:Flies.
I
Eggs.I
~2/ lj3!\ 12.0 p.m. Fi pcci nw m:-; W('l'
~2/1/:35 +.0 p.m. 0 0
~:3/1/3!) 0.30 a.m. 0 0
\Vcatlwr <·loudy,
U.O p.m. 0 0
Clouds broken.
:2.0 p.m. 0
:'+/l/3."i 9.30a.m. 0 12.0 p.m. 1 L.s./ I
!M.d. I 2.0p.m. 2:\Ld./1 :!:ijl/3-"i 9.30 a.m. 0
M.d. = .Musca domestica.
L.s. = Lucilia serica.ta.
0
0
+/1
-1-I J -j-/1
8.h. = SarCOJihaya haernorrhoidalis.
2.i\f.rl. /2 = 2 M.d. at 2 beakers.
Oleum Picis (Commercial)
:Mag-
gots. Flies.
e set 0:1 t. 0 2~'l.cl.12
0 I i\!Ld./1 cool wi nd.
0 :2~Lcl.f I tempera tu rc rising .
0 2 L.s./:?
2M.d./
0 I L.S.fl 4:\i.cl./2 0 J L.s./1 M1.cl.1s 0 +M.d./2 li'>L.s./
20M. d./:!
Eggs.
0 0 0
.J...j2
-r/2 +/2 +/:?
-,/2 lVIag- uot.;;:..
0 0 0
0
1-;1
+/1 +/:!
+/2
~-/1 = Eggs or larvae present in one beaker.
420
Controls.
Flies.
i\:\Ld./3 0
0 0
2L.s.j 0
H'Vl.d./:~
GL.s./:1 10M.d>3 +:3
IS. h.
!J:VI.rl.j:3 -i-;:~
:lL.s./3 , ;:l
!I M.d. I
:lL.s./ T 13 21M.d./
20L.s./ ..!_; :~
2."iM.<L'3
0
(J
()
S.h./1
-+ ... :~
+l~
+;:;
+,:l
1t will bP seen that the tagetPs oil ,qs Yer.'· dfectiYe, particularly in c:omparison "·it!t oleum picis. The latter does not show up ''ell bec:ause t'he quantities of the repellents used ,,·ere small, but this was done sin('e it bad bee11 deterlllinerl in other simiLu te:-;b m:.llle pre,·iousl_,. (not here recorrlerl) that the tagete:; oil appeared to be stronger than olPum ]Ji('i:i i u 1·egard to l'P]JPllent llrOp<'J·t iPs for hlow- tlies.
lt is not the intention to rt'l·ord in thi,; preliminary l'P]lOT( all the tests that have Ue!:'l1 lliaclP, but to gin a fp~y typical results obtaille<l afte1· the first t.est·s made for orientation had he en canierl out. The ,,.orJ, is bring continue<] i11 Yarious rlirec!ions <111<1 more iletail c-ould he g-i,·en in a later :n·ticle.
H. 'l'FsTs : :-; Ou ·.\cTO)tETFIL
:Since 'l'agele::; oil Ita::; a w ry c;trong ollour it was thuug·ht t'haL Lbi.s mi.gbt ::;iJIIJlly mask the· o<lotll' of hails used and it was t lwrl'forp ilf'l:ide<l to test wltd her t.hp oil has definitf' l'l'[ll'llent propNt ies fo1· flies.
The t~·pe of olfadon1eter descrihe<l by I\.ryg·sman (l!J;W, J!):JL)
\\·as construdP(l and tried. lt \l·as found, hmYeYer, tl1at th1• l'entral box in '' hi('h t'hP Hif':; are pla1·e<l wa,.; too largP anrl that the fl.i.es only accidentall,\' entPl'P(l the h1·o tuliP,; at thP sides. MoreoYer, it appea.re<l from other tPsts tl1<1t the Hies clo not easily t>nter into a
t·ube ,,·hich has no YPntilation except at ih rnh:11H'P.
The apparatus shown in Fig . .1 ,,·as c:oustruct<~d after seYeral trials and is heliewcl (o sati~h the requirPments of flip,; such as hloii'Aies, honsdlie:· ancl otht>rs,' ,,·hi.C''b, m·e snfti(·it>nll,,· :H·ti,·e. The apparatus has alsu h<•en triPd for mosquitoc>s, but thew have the habit of sPilling <lo\\'JI in n suitahle ,;pot <11111 do not n1oYP al)()ut sufhC'iPntly to g·in· tlw desirrd rbult.
The apparatus C'Onsists of a box <l, mea::;uring :tLout 05 by 15 hy J.!) C'lll. The entrnncP is guarded l>y a gam-:e " sleeYe ",the Rides ('Oitsist of ,,·ire sn l•en and thr-• exit i.-; <·mdroliPrl 1>.\' fliP :;licling door H.
']'his lra<ls into a slllall box (', me:1:;uriug 12 hy 1:2 b~· 12 em. Its top anll front are mnclE' of glass, the rest heing lJJPtal (or woocl), ancl each si.cll' contains a r·ircubr opening of 7 <'Ill. diameter Sll!Tonnde<l ou the outside b~· a short pnljrc-t ing ('o] Lt r. Furl lll'r are rf'quirerl ,.;f'YPral tnhes. "·hiC'h ('au lllost r·on,·<·nientl\· hP made of celluloid, measm·ing tiO l'lll. in length "·itb a 1lian;eter of 7 Clll.
'l'hey JlJust fit. \Yell into thP lateral openings of hox C'. Each tuliP
IS provirlecl with four long-ih1dinal UJ>ening:; or ·• n·indo,,·,;" whir:h are C'OYered with gauze doth and these must be equally laro·e and e,·enl,,· spaeed in all the tubes. These windo\YS proYide >Pntilation an<l preYent the smell of t·he repellent testecl from spreading through the ,,·hole apparatu~. \Vhen the apparatus is nsell the windowR
II. 0. ~tQ).'l\'1 , .
should therefme face upwards. 'l'he top and front of box C IYere at first macle of wire gauze, hut it \\·as found that the flies woulcl then not readily enter into the tubes.
'l'he apparatus is :;et up a;; shOIYil, thP end~ of the tul>P~ beiug plugged witlt c·otton 11·ool ancl the box C facing- to11·anl,; the light.
It is best to work in a large room where there i~ no draught and not too nf'.ar .a 11'inclo11·, pbc·ing the npparatu,; in such a position that the lig·ht· i,; llislributecl as en'nly as pos~il1le m·er both the tulles. 'l''hi;; lig-ht factor is Yery imporLmt. About (i0-~(1 fhe,; an-• plac:ed into box A and lltey will soon pa,;s thmug-lt iuto C. 'l'hr lraplloor TI tuay JlOII. bP dosed, hul as a rulP the Hies "·ill nol return into lhe darker box A <111cl thP OIWn door proYiciP,; furthc·r Yeutilation, keeping the . ntell of tbr repPilrnt from entering the blank tulJP.
A blank count is first maciP, ;~fler ;tilOII·ing the flies a fPII' minutes to g·et accustomed to the <~Jlp<tratus. ('ountH ma.1· hn ntade Pl·er~· :10 or GU seconds and :!() counts are lllacle in <til. Unh thf' Hies in the
·distal half of eac·h t uhe ,.;'houlcl l>e counted, antl f~r thi,; purposP it is neeE's~an· to clra11· a line arouncl thP micldle of rarh tube. lt 1s
conveJJi<•ntvin thr intrnal beh1·eE'n counts to k.Pep c·ount of the flies in one tubE' ~o that at the C'orrec·t moment attPnlion c·an lJP g-iYen to Lhe othE'r to rPg-i~tPr the nulllher tlwre. \Yiwn repellPnt has hreu introdu!'ed into one tullE' the Hies in this tHbe ~ho1tlcl 1JP 11·atc-'hecl in onlPr to SE'P ho,,· the.\· reac·t to tiH' lllatPrial 11·hen tltP\' C'Oille near it.
The· pnlilllinary blank count will ~how 11·hether the di,.;tribution of lig-111 is ~uHil:ienll~· PYE'll on hoth sides. :\rC'ess;lry alljustnlE'nls sh011ld be made. A clrov of the rrpellent is no\\· plal:ed on to a plug- of c·otton ll'ool ;mel t'lt.is is slipped into thP plac·e of a plug on onP silll'. BPg-inning nftn a fp"· tninutrs 20 counts ;~re Jttacle. The plu;.t with iltP repPllPtlt is replaced b.1· a clean one and lite tliPs are then chaserl hack into C' hy pushing the plugs into tlH· pmximal ends of the two tube:;; thP_I· :m" further bmught· inlo A h_,, tuming this sille to lhe light ancl pi<IC'iJtg a clark cloth owr C if l!Pc·E's~ary and thrn closing the-· clom· H. J<'rPsh tu1ws arP in~PrtPcl, t IH• rPpellrnt JJeing· llOIT placrcl or. tlw oliwr sicle, and the Hie~ an .. allo11·eti lo return. 'l'he n pp:urd us shmllcl lw replacE'rl exadl.1· iu i l,.; previous position. "\notlwr :.?0 !'Ounts arE' ntaclP. frpsh tuhp,- ap;<lin in.-;erl.Nl ancl finn!ly 20 hJ.tnk l'OUnf-s COlll)llete the tP.'it. fn~lc~acl of inserting fresh tuhes for the ~pc·oncl c·ount 11ith !Ppellent the 11·holP <l)lp<nnlns ma.v .-;imply hr tnnwd upsiclP clown. so that tlw repPllent is nmY on the ot·itpr sicle, l>ut· c·:n·e musr he LtkPIJ to rrg-ai1t t'itP e;.;:Jd J>reYiou,:
position \\·ith rf'fpJ·ellC'P to the ~out·c·p of lig-ht. 'l'l1e c:ollltt,; nrP fin:1ll~·
SUJlllllPci l l j l Hncl. if llPCE'SS<U\'. ('OJTPctions rtrP lllHflP :t~ inclic·atN] h.1·
the 1Jlank c·oHnts.
1. FliPs: .lf11sca rlo!ll('stint, (,ltCilirt sc1·icata, Clu·ysom .ljia lllllir-l'/1-', Clu·.IJsOIII.IJlO. chlot·n/1/JlJa and Snrcoplw.r;a lwelllOI'I'- 7/{)idlllis: T11P blank C"Ounts 11·erp strffieiPnth evPtJ.
Ht->pellPnt. CiF\: Plllph· tullE'. 200. . 42:3
A NEW 1-'l.Y JtYI'J·:J.LE:\T .-\:\1) lll.O\\'l'LY l>RESSlXG.
2. Flies: /,ucilla seri~;ata, ChTysomyia chlorupli/J/Ja: Repel- lent, 5fi; empty sirle, 2cJ!L
;). l<'lie;;: L·ucll/11 scric11to: Repellent, 70; em]Jty sitle, 21 t.i.
In this casp a fe"· Hies 11·erP apparently overcomP h_,. the tag-etes oil and they renwin!'d in the end of the tuhe in a tlazetl co1\(1ition during the rPRt of the !'ount, hPing- counted Pach time.
4. Flies: },uolla sericafu: Hrpellent, !i0; en1p1,1· :-;ide, 749. 5. Contparative test 11·ith oleum ]Ji!'ic; and J.ucilla sc·ril'llfa:
l~rpellent, 2-l:S; empt~· sidP, :~47. 'L'Ite oleu111 pi cis tlor;;
not show up \\·ell in i.lti,.; <I[Jparatus. Flie,.; \\·ill even
~Ptt le dmn1 ou t hf' plug- ('f\lT\·ing- tht• material.
It appe<J.rs therefore that tlw tng-Ptes oil has definite repellent ]Jroperties, antl it has also Leen notieetl that hlmdl.ies approaehing a wound whil'b has bee11 treatetl ,,·ith mixtmP" containing· the oil will rapid!.' tl,v oH "·ithout srttling· do\\11.
c.
'rEsTs '''~'nl L,,RvicwEs ..it is nut nPt·es::;an· here to reeount all the t.est.-; made with tlifterent material", most of '\\'hich had been tp,;ted before h.r ot.her workers. No ot'her snhsta11ce that could l>e u;;eu on a "·ound was found to he eYen nearly a,; effeetiYe as t.;arhon tetrachlorirle aucl tetra-
!'hlorethylPoe, lJoth kno1Yn to he strong insedit·i<les.
The test~ were made as follo'll·s: L'ucilui .sencala eggs ,,·erP cullede<J l>y allO\\'lllg' the flie,; to lay Oll small piet·es of liver. 'l'bP larv<le \\Pre allo"·ptl to \le,·elop in suitablt• ~111Toun(ling,.; 1mtil they began to mign.th• from the foo\l material. 'l'ltesP fully-tlevPlol>ed thirrl stagP lnn·ap are lmo,,·n to bP the most resistant st<tge uml ,,·erP u,;erl in ortl0r to maintain thi,; far·tor a;; r·on,;Lmt as possible.
As a rule 20 larvae 11·ere placed in a suitable t.ube and the mixture to he testecl \\·as pourer] OYPI' thelll to <I depth of <lhout 2·5 em. The tuhe ,,·as gently ,.,·hakrn antl the period of readion ti1uetl by meaus of a stop,rai<-lt. At the en\l of tlH• tinte tltf' mouth of the tube 11as euvererl with a pir,ce of' gnuze dotb, the tul>e turned up:iide down a1Hl shaken .-;o a,; to drain the fluid off (j11ickly. 'l'hP larYae were 1 hen tran,Jen ed to tubPs r,ontaining- clean sanrl and ihesP tuhes wpre elo ... wrl "·ith gauze cloth. AfiPr allowing sutfit·ient time) for p11pation and emergenr·P of !'llP flie.-; antl aftPr the latter harl dietl, thr-• contPnts of ear·l1 hthe were sivecl out arul the number of tlt·arl l{lrY<lP, dPnrl pupae anrl flies <:ounterl, as reconlerl below.
fn orrler to en::;ltre satisb clorv l'Ontad l>etween lhe material tested aud thP lan·ae it \\·a.., tl~·ei<lPd to Pnmlsih thP YolatilP l'ubstances !'ur·h as carhon teha(ib1oricle, tetrac·hl~rdh~·lenP anrl
424
H. 0. )10!\~IG.
benr.ine. Oily mixtures, "·hen applied to \\"01.mds, have the undesir- able effect of softening the tissues and preYenting the formation of a healthy scab. \Vatery emulsions dry off rapidly an<1 only the less Yolatile portions remain on and around the \\·ouncl. The mixtures used in the tests recorded belO\Y ''"ere not all satisfactorv emulsions
as will be discussed later. ·
For the sake of brevity the following abbreYi.ation,; are used:- 0014 = Carbon tetrachloride, 02Ct = Tetrachlorethylene, 'l'.ol.
Tagetes oil, G.ar. = gum arabic, Aq. = \Yater (rlistillecl).
!l1ixturc.
l. ·Hcnzine 10, T.ol. 10, G.ar. 5, Aq. 75.
2. 10, 10, 5, , 75.
:3. 20, 10.
" 5, , 65.
4. 20,
" 10, ., 5, lead ace-
tate :1 °1~ 6.5 ...
5. 20, G.ar. 5 Aq. 75 ..... 6. C2Cl4 10, T.ol. 10, G.>ll". 5, Aq. 75 7. Aq. 100 (42 lan·ac) ..................
I.
Time of Reaction in Mins.
:~
3 3 3 3
Dead Larvae.
1 0 18
20 18 18 0
Pupae. Flies.
2 12
0 20
1 1
0 0
2 0
0 2
3 39
It is seen that 10 per cent. benzine even for 3 minutes is not sufficiently effective and compares rather unfavourably with tetra- ehlorethylene; 20 pe1· cent. g-ave better results but was dit;appointing in subsequent tests. The lead acetate was .arlrled on account of its fayourable effect on wounds anrl it did not break the gum arabic emulsion.
II.
Mixture.
Time of Dead Reaction
Larvae. Pupae. Flies.
in Mins.
2 u (j ·' ..
8. Benzine 20, G.a,r . . 5, Aq. 75 ........ .
2 1 0 19
2 20 0 0
!l. , 20, 5, 3% lead scetate 75 .. . 10. C2C14 20, 5, Aq. 7ii ........... .
2 20 0 0
2 19 1 0
I J. , 20, fi, :3% lead acetate 75 .. .
U. CCI,, 20, i'i, Aq. 7ii .............. .
13. , 20, 3, :3% lead acetate 7:) .. . 2 12 6 2
1 1 0 19
2 0 0 :W
14. 'r.ol. 10, , .5. Aq. 8ii ............ . L). :~o~ lead acetate 100 ..................... .
2 425
A ~EW FLY REPEI.J~E:\'1' AND llLO\YFLY DRESSIJ'\G.
ln thi,; case the lead acetate ap1Jear" to haYe coLmteracted the effect of benzine and to a slight extent <1lso that of carbon tetra- chloride, but this is probably not the correct interpretation of the
n~sult-see 3 and 4 above and other tests below.
Tagetes oil has no appreciable lm·vicidal effect. lt "·as decide(1 to try '"oolgrease as emulsifier, since this "·ou1tl be particularly suitable for use on sheep. Emulsions wit'h lead acetate were, ho,r- ever, not satisfactory and apparently did not bring about satisfactory eon tact between the insecticide and the larvae:-
III.
. Mixture.
16. C2CI4 20, T.ol. 10, woolg.rease 5, 30' !o !carl acetate 6fi. 0 0 • 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 • 0 17. , 20, T.ol. 10, G.ar. 5, 3% lead acetate ();)
18. " 20, woolgrcase 5, 3% lead acetate 75
19. Benzine 20, T.ol. 10, 'voolgrcase 5, 3% lead acetate 6ii. 0 0 0 0 0 0 0 0 0 0 0 •• 0 • • • • 20. 20, T.ol. 10, G.ar. 5, 3% lead acetatE'
65 ... 0 0 0 0 0 •• 0 0 ••• •• 0 •• 0 0 0 0 • •
21. " 20, woolgrease 5, 3% lead acetate 7;)
22. Aq. 100. 0 0 0 0 •• 0 0 0 0 0 •••• 0 • • 0 0 • • 0 ••• •••• • •
Time of Reaction in MiM.
2 :2
.)
2 2
·) . )
Dead Larvae.
;)
20
()
0
. .
, )
() ()
Pup<:<' . Flies.
0 1ii
0 ()
:2 18
1!l
1 ](i
0 20
0 :W
Soap emulsious \rere no"· tried and it was found that the substances tested could very easily be emubified as follows:- Benzine, CCI., or C2Cl., 50 cc.; Tagetes oil, 25 c.c.- .\. Soft soap, 9 gm.; "·ater to make 25 cc.- B. A(ld successive small quantities of A to Band shake. The thick emulsion is diluted with 160 cc. water, giving the following concentrations: CCI., 20 per eent.; Tagetes oil, 10 per cent.; Soap, 3 · G per cent. In these tests 40 larvae were used in each case.
IV.
Mixture.
23. C"Cl, 20. T.ol. 10, soap 3 ·6, Aq. <tel 100 ...
24.
25. "
26. CC14 20, 27.
28.
29.
:'lO.
n.
:H., Benzine 20,
"
v\'atcr ..... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0. 0 0 0 0 0 0 0 0. 0
Tin1e of Reaction in 1\fim,.
:2
:~
1 2 :'l 1 2 3 :l
Dcarl
Lal'vaC>. Pupar. Flies.
.) () :3;)
27 :l lU
2+ (i 10
10 7 2:l
34 :; 1
:39 1 0
·) l :n
0 :l :37
2 j :l7
:2 37
'fhe above test showed, as had been noted before, that CC14 arul C2Cl4 were more effective larvicides than benzine. Since tl1e tem- perature of the sheep's body would probably have an influence on
426
H. 0. ).IONKIG.
the reaction by inereasiuo· the respiration of the larvae, the above test \Yas repe~teu with the morlification that the emulsions were warme<l in a water-bath to 28° C. before being p011re(l on to the lnrYa<.'. T n each case 20 larYae "·ere used.
v.
Time of Dean
}fixture. Jtcaction
Larvae. r" 11pac. Flies.
in Min~.
:.;a. c,c1., 20, T.ol. 10, soap :3 ·6, Aq. ad. 100 ... I 7 l 12
:34. 2 19 l 0
:~:;.
" :3 ~0 0 0
36. CCl, 20, 1 4 11 5
37. 2 20 0 0
38. " 3 :lO 0 0
39. Benzine 2-0, I 1 1 18
40. 2 0 l 19
41. " 3 2 I 17
.u. V\'RtC'r ....... . ... :1 0 0 :W
\Vith regard to the reaetion~ of t'he larvae under the influenee of these em.ulsions it "·as observed that CCl, stunneu them almost immediately, \Yhile C2Cl4 appeareu to irritate them strongly for a fe\Y seconds before they quietened llmYn and became motionless. It was thought that thi::; property of the latter chug might be favour- able, since it \rould cause the maggottl to crawl ont of (leep \YOtmds before they \Ye1·e killed. Tests made on sheep, 'hmYever, showed that C"Cl., unfortunately irritate,; the wound and the animal to a similar (legree and that it harl to be disnarclecl for thi;; reason.
It was further found in testing Yarious emulsions on sheep that the free alkali of soft soap was irritating anrl the soap emulsions l1 ad to be given UJJ. IV oolgrease vvas again trierl and <>a tisfactory emulsions could he made iu the follo"·ing wa,v:-\Y eigh oft into a sni table flask 60 gm. "·oolgrease; measure off (A) 200 c.c. CCl.,
+
50 c.c. Tagetes oil (it ha(l been found that 5 per cent. of this oil is sufficient as a repellent in the mixture); measure off also (B) 700 c. c.
\\'ater. Add about 20 cc. of A and 100 of B to the woolgrease and
~hake or stir to emulsify, then add more \Yater ::wd, if necessary, fur- il>er small quantities of A up to 60 c.c., shake to emnlsify aml p:o on a.rlding water until all of B has been incorporated. Then add t'hP 1·est of A and shake. O"·ing to the fact that woolgrease contains small quantities of free acid, the emulRion will not ·keep \\'ell. A fe1Y rhops of phenolphthalein are therefore added- a bout ] 0 drops to the above quantity- and the €mulsion is neutralised b:v adding a Rmall CJUantity of 10 per cent. NaOH solution. After a few (lays tlw pink colour of the indicator may disappear on account of the liheratio11 of further small CJUantitie~ of acid and nlkali shoulcl be again aclrled in sufficient quantity to neutralise, or sufficient ma:v be added the first time to giYe a definite pink colour. Since different samples of \Yoolgrease vary in acid content the amount necessar:v eannot he stated definiteh. h'•t 12 e.c. of 10 per cent. NaOH to a litre of emnlsion ma:v hP an aYerage quantit5· to go b;'i·.
427
A ~EW FLY REPELLENT AND ULOvYJ!LY Dlt:ESSI.:\G.
The emulsion may also be made by leaving out the Tagetes oil at first and adding it later to the neutralised emulsion of woolgrease, CCl4 and water.
'rests ''"ith the above emulsion gave the follo"·ing result:;:- VI.
Time of Dead
Mixture. Reaction
Larva0. Pupal'. Flies.
in Mins.
43. CCJ 4 20, T.ol. 5, woolgrease 6, Aq.ad. 100 (25°C.) :.W 0 0
44. :2 :20 0 0
45. 3 20 0 0
46. (:WC.) J :20 0 0
47. :2 :.W 0 0
:~8. ., ., 3 20 0 0
49. Water ................. ... 3 0 0 20
'rhe .above result was so satisfaetory that it "·as deeided to repeat the test and also to try 10 per eent. CCl.1 in the same emulsion. In test VI, the room temperature had been 25° C., in test VII it was 21° C., and this was also the temperature of the t>mulsion (40 l:.uvae nsed in each (:ase) :-
'nr.
Time of
Dead r
Mixturr. Reactior, Larvru·.
I
Pupa<'. Flic,.
in Mins.
;)0. CC14 10, T.ol. 5, woolgrease u, Aq.ad. 100 (2l°C.) 22
I
. ) j(j:a. :2 :2:2 \) !)
.:)~.
CC11 20:T.ol. fi, wo:;l)'rea~e 6, A~t.ad. 100 (2i~C.) :{ 20 l:l I
53. :w 1 ()
M. ;{9 l 0
55. 2 :)6 4 0
56. 3 40 0 0
57. (30°C.) 40 0 0
58. 40 0 0
;)9. ~ 40 0 0
60. :1 40 0 0
fil. Water .... . ... 3 0 17 2:{
CC11 10 per een t. is a pparen tl:v not sufficient and it ma.Y he advisable to keep to the 20 per cent. emulsion. 'rhe fact that 17 pupae failecl to emrge in the case of the control may redure the value of the test to some extent. However, in Nos. 5G-60 the larvae never moved afte1· having- been immersed but graduall;.· h1nwd black aud clriecl out.
·with regard to it;; larvicidal effect this emulsion may be l"Oll-
sidered as satisfactory.
428
D. TESTS OK SHEEP.
\Vbile the mixtures ~md emulsions 1le~nibed .aboYe \\·ere being tested on larvae, they \Yere aLo teste1l on iufested ~:;heelJ, as aln"'a1ly indicated, and the satisfactory lan·iei1lal effect of carbo.n tetra- chloride, a:; 11·ell as the fly repellent properties of 'l'ag-Ptes oil was clearly demonstrated.
'l'he requi1·emenb of a good blu1\·fl.1 mixture are: (1) SLrong larvici1lal efted; ('Z) ab~ence of i 1ritation and interference with t'llP healing· of the wound; (=l) pre1·eution of re·infestation until thP 1round i~ healed.
'l'lte emubion described aho1·e salisfie:; llte;;e requirelllents lo a high dPgree. 'l'he b n·it'idal etreod i.~ e1ninP1ttly satisfactory. 'l'hP t:arbon letrachlorille-\\·oolgrP~he eiHubion 11·ilh Tagetes oil has YPI')' sligbl irritant Jll'Operlies, if any. Some ,.;beep will be uneasy for a fe11· momPnts after t'he application of the emuLion, bul thi;; pnsses oft very l[llickl.v alld there is 110 sign of irritatioll or inlPrfen'lll'l' 11·ith the healing of the 1\'0Ulul. 'l'he 1nilPr has applie1l I he emubio11 to a fresh abrasion on his h:llld and nol it'ell uo irritation whaiPH'I'.
'l'he emulsion has been Lested ou a b irly large ntllll her of t:asp,;
11·itlt moderate to Yery larg·e \I.OUJHls and in Jl(l ca~e diJ re-iufestnt.ion ot:cur, exeepl in one shePp ll'itic'h l:l.1· prostJ·ate and was repeatedly
\YPttetl by rain. 'l'hi~ case \Yas re-infeclerl fiYe Jay~ after the firs!
trea tm en t. 'l' he Pmu lsi on breaks soon u fl:e1· it has bee 11 applied i o the \\'Otmd. The l.anae are killed 11·ithin a minute all!l thP carbon telrachlori1le :u11l 11·atPr t:>vaporate fairly soon, lhe length of limP required Llepcuding on the htlltlidit)· aml temperalnre of tlw ahnosphere. 'rhe wool-grf'aSP a11d Tag-etes oil settle dm111 in tlw
\HJol :smTomuling the wotlllrl ;mrl the snwll of the oil i~ ill evidencP for 10-14 da,·s. 'l'ltP 11·oun.l i~ u-;nallv rln· ~tftf'l' 24 l10ur~ :tnrl hPab
1 it pirlly. · · .
'.L\•sb are nm1 being ,·on(lude1l with this emubion unde1· ,]iHPrelli co1Hlitions \1-ilh rPferPttce lo f'limnte. pasltnP. ell'.., and nl~o ou t':lttlP .-;uhje<'l to atin1·k hy lhe sClYI\--II·orm ('/n.IJSI!III.IJIII, lw::zio1111. Tn oJll' citsl-' a fnrmer tre:1ted ~~ numher of infPsted cal·tlP 11ith I'O!llpleil'
stttTe~~. no l'P-infPstal.ioJI occulTing. The 1·efmlls of other 1P.-;l:< .arf' 11ol yet. itvailahle but will lw repoderl upon al it later rlah·.
It has bee 11 fo uncl th~tl t'b e 0 per 1·en t. 'l'agetPs oil c·;m he repla f·p.\
hy ·10 pe1· <:enl. Olcnm pieis, hut cases of re-infeRtation h~tYf' ou·tiiTP.!
'"'l('ll Ruch an em ul~ion ~~·~1s usf'd.
Il i~ sbo\1'11 thai thl· slc•a11Hlistilled oil of the plaut Tor;rtcs minima has strm1g- l'f']Jellent propertie~ for hlmYflies aJ11l that it i~
suitable for 11se in a Llmd!y 1lre,;si11g-.
Carbon tPtrachloricle and tel.rach lorethylPne an) eXI'f~llent brYi- ci\les for use against Llmdl~, 1nagg-ots, hut t8trat'hlorethylenP is irritating· on \YOUlllls. Both the~e druo,; are 1lislinctlv more pf'J\•din•
than benzine. "' ·
4?9
.~ KEW FLY REPELLE::\T Al\D :ULO"TLY DRESSIXG.
Emulsions of the aboYementioned substances are suitable as blowfly dressings and \YoolgTease was found to hA the most satis- factory emulsifier.
Particulars are gtven m regal'Cl to the p1·eparatiou of a suitable emulsion.
REFEREKCE.
1\.RYGSMAN, ll. J. (1930. 1931). Reizphysiologiscbe ("nter'lH'hungen nn Blutsaugenden Arthropoden im Zusammenhang mit ibrer ~ahrungswahl.
I Stomoxys calcitrans. ZschT. f. veral. Physiol., Abt. C, Vol. 2, pp.
702-729. 11 Lyprrnsi11 e:x:irJtW. Idem, Vol. 1:3, pp. Gl-73.
