Evaluation of permethrin (OMS 1821) furnished by shell as larvicide against simulium Damnosum S. L.: I. effects against S. damnosum S. L.

rl\ WORLD HEALTH ORGANIZATION ORGANISATION MONDIALE DE LA SANTE ONCHOCERCIASIS CONTROL PROGRAMME IN THE VOLTA RTVER BASIN AREA PROGRAMME DE LUTTE CONTRE L'ONCHOCERCOSE DANS LA REGION DU BASSIN DE LA VOLTA rn repry prcrrc rcfcr ro: No VCU/O194 19tb Marcb L9B4 EVAfTUATTON OF rEmmrI{RIN (Om reer) rumrrsml BY sllEr,l AS A IARVICIDE AGAINST SIMUI,TM,I DAM}IOSUM S.I.1 I. EFIECIS AGAINST S. DAI'1N0SU1'1 S.I,. NISECTICIDE Zyft az1. EC (reglstered, name [al'cord - Code SI0 6241 - 3ot PS ,74/er) was provlded by She11. TEST I\ETHODS The close-clrcuit tror:gh system wa"s used for prell-ulnary testlng, followed by rlver trials. (See Annex 1 snd 2 fot detalLs of method.e). TEST SITES Eva}-ution was earried out by OCP (Onchocerclasls Control ?rogra'nrns) staff ia Southern Iogo, outside the area reguJ-ar1y treated by OCP. Si.mrllYg da.urogun s.1. larvae used. for the test were obtained from sltes where lalvae are believed to have no::mal susceptibility to all lnsectieldes. Howevert susceptibillty tests in Ivory Coast against }arvae resistant to tenephos and chlorphoxim showed the resistant larrae to be J to 5 tirnes more ausceptlble lcoxnatsurons a. Tests on S. da.mnosun(i) vcE, ffi'ssrs. ocRAN, REIIAITD & BARRo(fi) VCU' ouagad,ougou: Drs. KInTAK & SIIBnA(ril) pilots: Mssrs. cofTER, trBDlIcH & MoIAUGHIIN b. Tests on non-target fauna t VCU, Ouagadougou: Dr. PAUGY, Mssrs. YAMEOGOT'BIHOIItrI & COUIBAI,Y i 2thap thetrnotrB-lrrstrain i-n fogo. Because of th-is obsematlon, trough and' rlver tests were carrled out ia Ivory Coast. They conflrned that the effective field dose ln Ivory Coast is less tlun ln Togo. Studies are lnderrray to dete:mlne lf thls effect ls clue to a rrnegative correlationrr with organophosphate resistance, a sIlght reslstance to pyretbrolds 1J!I Togo or a slmple geographlc variation. For the evaluation of the effect of per- methrla on the non-target faura, lt has been asguned that the hlgher effectine field rlose observed !: Togo w111 be necessary for operatlonal use. HESUTTS A. frough tes_ts Results from trough tests a.re surilrarlzed 1n table 1. Data for tenephos, the standard OC? larvlcide are shovrn on table 1 for comparism.. The product is more acti-ve tlun temephos, with observed trtOOt" of 0.012 to O.Ol8 compared with O.l1 to O.27 for temephos. This differenee ls clear at the leveL of the ICr, for mature larrrae (O.OOe to O.OO9 vs. 0.065) as rve1l as at the leve1 of the rcro (O.oO12 to O.oo15 vs. O.OOB for ternephos)' Tglcord shows a large increase l-n concentration to go f1.orr. 90% mortality to lOOf. This was true both in Togo and Ivory Coast. For this reason, testj.:rg concentrated on determining the ff100. lrOO% effectineness is necessary in OCP operations, both for epidemiologieal reasons antl to avoid selection of resistant strajls. In terms of Iarra1 behaviour, the larvae become agltated a1rnost i-nstantly. After 5 rolnr nany stop feeding, ald some detach even at low concentrations. Ihere 1s up to 6oy'" detachment at the higher concentratlons after 10 mj.nutes. At lower concentrations, paralysls lntervenesr with the older larvae renairring attached in dlstorted positions. There ls no errldence of recovery of morlbond larrae. B, River trials Results from 4 riner trials are sutnmarized in tables 2 and.3. These resuLts shovr that tl-re ninimr:m effective field dose lF between O.O1 -t 5an6 O.O2 dt for 10 miautes (i.:e fogo). Tests R8r-8 ancl R8l-12 produced a carry sj-rnlIar to temephos at 1O x the dose (0.1 ng/I temephos at a tew m5/ sec gj-ves about I h of LOS" reductlon). The relatively poor results obtained in R83-18 are probably due to the fact that the river was d.rying up ancl flow between rapids was very s1ow. However, the results of RBl-15 in the sane river at twice the tlose and a higher d.isclrarge were also rather pgoro Unfortunately, we eannot exclude the possibility of an rrincreased tolerancett to pern,ethrin due to agricultural irse (on cotton) on the banks of the rtYer. IIo river trials have yet been carried out at hlgher discharges. It is hoped tirat this will shorv a performance equivalent to tenephos (20 lcm of lOOf reduction at 100 m1/see). C. Cornmen ts on the physical ProPerties of tle foPgfglions The formulati-on spontaneously for-ns a fi-ne, vrhlte stable emulsion and. is thus suitable for operati.ona'l use. II. EEFECTS O}I NO}i TARGET FAUIIA COIIDITIONS AND TMTIIODS See annex 5. RESUINS 1. Gutter The results are presented in Figr:res.I amd 2 which shovr the percent- age of individuals of the major ta:ca remaining in the gutter at various tlmes after the applicatlon. The total- number of individuals in each taxon present at the beginni:rg of the experiment is given on the 1eft. The results at O.O2 ar:d O.Ol-5 ng/l xe very similar, and the resr:m6 vrhich follorvs applies to both. , Invertebrates began to detach JO mlnutes after the applicatlon of tlie chemical. There was a strong effect on the invertebratbs. Most of the taxa were redueed by at least 50% wi.thin JO minutes. :t 4- The Chironomidae were the only group not severely affected, with 5-JI1rt detachment. Even among the Chironomidae the less numerous Ortho- eLadii::.ae were sensitive, with 4{" aetachment. The Chlronomlni, Tanypo- dj-naer md Tanytarsini were less affected. On the other hand the Ephemeroptera, which showed 90-95/, reductlon, were even harder hiit than Sj.tnu]-ilm damlosr-ur. Finally the Triehoptera were also very sensitlve, bejng reduced to less than +O% of the nunbers before the test. fn thls Broupr the yourger instars (f-Z) were almost completely removed by the insecticltle, whereas about 5q, d the older larvae (3ra instar and abo,re) detached. Cher:matopsyche sp. were the least affected (t{, aetachnent), They were very comron in the test at o.O2 n&/1, whlch explalns why the Trichoptera as a whole yrere less affected in that test. 2. Surber The results are presented in Table 4. They confirm what was found in the gutter. The Epheneroptera were slightly less affected (7ffr at 0.015 ndl) tiran in the gutter. The Chironomidae were reduced somewhat more than in the gutter, and the Trichoptera by the same arnount. Overall , the remainirrg Invertebrate fauna shorved a much hlgher proportion of Chironomidae a:rd a much lorver proportion of Ephemeroptera. No effect on l\lacrocrustacea or fish was observed duri-ng the passage of the lnseeticlde. DISCUSSION As a measure of comparisoa, flgr:re I (aata from DeJor:x, 19781) presents gutter data for terneBhos (an operatlonal larvicide in the Oncho- cercia.sls Control Programme wtr.lch 1s considered ecologically acceptable). It is clear that permethrin has a more drastic effect than temephos and that peruethrin r:se vroul-d requlre very careful eeologlcal monltorhg. .I 'lp,fOgx, C. 1978. Action de lrAbate sur les invertdbrds aguatiques. VI. Effets des premlers traltementg du Sa.ssandra. RapporttORSTOM Bouakd, Itro. 25, 22 p. mimeo. 5It should be kept in mlntl however that these results refleet the short-te:m effect of a single appllcatlon i-n a river not subJect to regular insecticlde treatment. The long-te:m effects of weekly treatment cor.rld be more or less severe. In the case of the Trichoptera, for example, which have a long 1lfe cycle p the drastlc effects on the youeg instars cor-rld' result 1n serj-ous reduction of the population o'ver the long-te::m slnce the oltler instars wou-l-d not be replaeed as they matured.. On the other hantl, past experience has shown that the fauna rtadJustsrr to repetitive treatments. Fr.on the ecological viewpointr e insecticj-d.e must be reJected if it produces a permanent structural aad/or quantitatine disequlllbrlum in the aquatic ecosystem. The results presented here cannot be used to decj-de whether permethri:r will have such an effect u:etiI an operational trial has been carrj-ed out. ft is essential to stress that the present trial was carri-ed out untler very lol discharge when the effects on non- target fauna are the most drastic with any insecticide. A lesser effect can be expected when rlver d.iscl:arges are hlgher. III. DISCIJSSIoN AITD CoNCI,USIoN The [alcord. zyl EC fo:mr:tation of permethrin is an effectlve Slmr:Iil.m damosr:m larrrlcide at a tlosing rate of O.O1 to O.O2 mg,/I for 10 mil1. Ehe product enulslfi-es spontaneously in the river and dlsperses well. The carrry is aeeeptable 1n reLatlon to the discharge. Although there ls no nortality amoll8 fish or naerocrustacea the effect on the non-target fauna is more severe tharr that of tenrephos. In thls respeet a long-te::m trial i-s necessar;4 before it can be decitled lf the product is eeo1o5ica11;, acceptable or not. The product should not be considered for routi:re use j:c small streans (or large rivers at lovr water) lvhere the volume to be appli-ed woul-d be verl, snral-I and j:taccuracies 1n meteri:rg equipment and streain discharge mcastLrements coufd lead to oYer- dosing with serious eeological consequences. a 6IV' RECOI,'I,ID]IDATI0I{ In operatlonal trial- 1n an entlre river basjn for 5 months to one year (ary and wet season eonditlons) wlth carefuJ. evaluatlon of the effects on non-target fauna should be caried out. The carry shou1i be dete:urlned at higher dlscharges. The nx1v1!nr:m effective field dose agalnst larvae reslstant to temephos and chforphoxlm should be verlfied. 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B8.9 44.4 9.9 t 1.1 248.9 1422.2 17.8 B.g 26,7 62.2 8l_7.8 17.8 5097.' 266.7 17.8 15.6 26.7 B.g l.7.g BB.9 g.g 275,6 26.7 t 5., 524.4 66t1.'t6357.8 aI TOTA.I IAUNA t oL3.7 727t.t 1, I I Fig. 1 <iAJ GI CD L7aJ -+)H+)E:) -9F\ LrJ a =M.LLU€ o-_ \r t- \ll G)o,F HrFA (_)r NL =gH ,E 2t- tt ;c)o a{- ET'c :5 o oE, r.rt '!,<5 oE oE CD r.c, c,:l G' Qc,AJe,cE! (3(,o G'+cf(= soo(] Es €* <ri EI +r ct oLo +, cnCLFofi,Glra= LF @oE' E.+Hln P* cL' +, *nr ,.J C\ ENo+ 4CLlrl otr ES 3got- I E o ! o c e / t. l,' I I t I I I I I I I I I I I I t I I I I I I I I I I I I I I I I I I I l I I I I I I I I I I I I a I I ) I I I I I I a t I I I I I I .2giF CP rtl, G, 6J cn t-o cf) C= LZ- CU+)H 't-)Ef,I9F[J ;-.. ==M.LrI S\,rtq lr \Qg) .taL). o_! =E sG otr3o Cts ED .5 c !6 EIE oE, tt) U,LfaE (\r oE F ato Q+ (=c\l o ooE Ea :(Y! E* ECI (v(vr\Iz, E)CF +tCLoLo EoECL ur oQ s oQlnLHE(\I €+ ui ooT' .a (E) .a@ Hll2;z,E U) oLfin E-g3*LF CIc E* Eu oF ) I I I I I I I I I I I I lr Ii I iI - )E o aaI(, qll I ---trI I r: j'j'j'j'j'j I Fig.3 @ lDL3o G.r S oE Lag(-) +) *$LJ\ =at-rj rL ol-r- q- OEr \g)Lr.I n- =3B -o =-A\= t, trc ,o 3+. cDc .a c '6 Eoe, 6.1 r.l:) (r, (e ar) (=(=tc) a EIt\.1 c=G)@ee soocDsNt=- €+ lri o C'tl <. =6Etr e: tJ7 oLo +t(Y)CLGIomtI(t= o ClE' .EE =(\rF+ ELI EIc Ep 3EoF +,CLo$lL(Y)or\EIc!=ECLtrl LF I I I I I I I I I I I I I I II I II , I I , I , I I I t I t I i ( I I I I I I , E o -i(, cq I I i .t AHrEr l SII{UIJTUU I/IRVICTIE SCREMInIG N'I TIM ONCHOCERCIA,SIS CONTROI PROGR/rJ,ltfll Hrthod: Clorrd-clrcult trough ttrt Brlrl dororlotlor ?bir rrthod nr drvrlopod for 00P la lfrtor by Dr. 8r Jernbrol brrod on I ty.trr rhloh br'edIr. R. oauglrr utrd orlrlrlvrly i,l hr fct ttrtr. It ber brra furthrr rodlfkd by tbr OCl lrmottollr trrmrrob ?rrr, Lorr, Togo. Lrt.'.. oollaat.d h thr flrld rr. rllouod to .ttroh throrclvor oE r rarortbl.plrtr lytu6 la tbr botto. of . tloutb riara rtt.r tl rrolrculrtrd vlth a pu.pr The plttr tr thrl trrar-frrrrd to r ..ooDd troEth lhrrr lnrrctloldt hrr rlrordy bcca rlrrd lnto thr roclrculetlng vrtr!. lf,trr I splelllc.:Potur. tlro, thr phtr 1r flnr,lly trrnrfrrrcd to a thlrd trough vlth clean vetrr vhrrr thr rortallty 1r uotcd rltrr 2rl hourr. tqchnlcrl dctrll a 'fhr trougha usrd trr oonrtruclrd of rlurlnlur and palnted vhlLo. 'Ihe t-,,rr:t,j arc BO c. IoDg, 15 cr vidc rnd I cr dorp. ?hly lrc clorrd rt onc rnd. at thc other rnd, a constri,::ad rrctlon or rlp,I! cr )'on3, 8.8 cr v1dr, end 2 cr drrp 1r rttrch.d. I rcoovablc rctrl pIaL6 rrsts rr tha botto. of thlrI1P' Yrtcr ls punprd lEto th. ororrd ond of tbo trough end flovr ovcr thc platc rn tho Ilp tnto r rascrvolrlo be rsplrrtrd by thc Purp agrla. srlll rlrctrlo crntrifu6rl purrpr vlth r dlschar6o ol about 22 l/a]n. ,^rt ulod, lrd tbl vrloclty ovrr tho sttsohr.lt pletr 1r rbout 0r?r/rrc. ror tho attAc))n.nt and ob.arvrtlonsyrtcrsr th. r.lrrvoir lr r plartlc rartr-buckrt boldlug about 60 llLrrr. for the sxporuro ryot.rr. l0Iltrc raarrlvrr' pot 1r urrd.t a ratarvolr to rrducr tbr uount of lnrrcticldr nocdod. Rlvrr vatlr 1r urrdot rIl ttrS't for routlD. t.tt.. rtr cherrotorlrtlcr (tcrpcreturc, pE, turbldtty) ara carcfurly notod. Lrrvrc am collrotrd by mrovlug thrir naturtl rupportr frot thr rlvcr. ihcy e.rr traurpoft d iEplrrtlc ba3s lu rn Lorbor. Ctrr 1r trtot to r.ptrat. thr larv& fror thc lor by A )oy.r of fratb ltrvrr orEratt' AlthoEah thr rqulprrat olD b. utaat rt tbr rlvrrrldr usl,ng a portrblc oloctrlc g.n.r3tot, thl typrof tcrt tr uruelly done lo r llborltot, rtlch lry bo rt sorr dlrtrncr fror thr collactln6 polat. ?br vo3otrtlon rlth tio hrver Lttrohrd k plecrd lD th. rttrch..!t trouRh. ?hr Irrvtr atturrllyIoeve thr YtS.trtloD to rorl r ltroEg.r otirrnt ed thu rttech to thr prrto ln tho llp, rhlch b.f tlh.hl3hrrt vrloclty ln thr troogh. ?hr leru tr. r.ft lot 21 bour. to rnrurr fln attachr.Dt. brrr nbtch PoPrt. durlag thlr prrlod en rltrlnrtrd Jurt brforr .rpo!ur.. ?hc plrtr urually oontalos about t,00 rrtur.Irrrrr rnd aav.r.l hundrrd youag luvu. Thr lervlcldo forrul,ltloo, .f. rpproprhtrly dllutcd rlth dlstnlcd vrtar t.rcdlrtGLy prlc toth' t"t' ?hr qulntlty a.o.ttlry ror tha lorort oonc.ntrrtion lr rddrd by pipctrc Lo thG r.!.rvolr of th. exporur. trough vtth thr purp runalng. ttr lnrootkldr ir allorcd to clrculat. lor 5 rtnutc! to obtrlD aunlfon dlcprrral. ldditloDrl larrctloldr lr tddrd to ihc rerr ryrtrr to obtf,ln ths hrEhrr ootrc.ntrrtlontin r tcrt rcrlor. Tbr plrto fror thr rttrchrcnt trough lr nov car?fully liftrd out rnd placrr.) for a dcllned pcrlod, usurlly 10 rlnutot. :n '-he !rporur. trough Larver drtrching durlng thc Grporur. pcrlod rrc caugJrt 1n a nct altechc4 !o tle ltp of th. trough. lftor thc.rPotur. P.rlod th. plrt. eod thr nrt ara tranaferrcd to I bo.i,l1aF Lr,)u,lh. lt lhc eud :f a 24-hour obrcrvttlon prrlod, tho dttrohrd lerver 1n thc nct, ls vcl,l as any dr.rd oras s:.rII aLtachad to :ht plate lr' pr.tort.d 1! alcobol' for countlag. (l flrst collrctlon lr uauelly na,Jc ., houri eftor rxposurr slDc' rosl lervlr dctrch ln tblr Parlod rnl tho lrrveo tey dccorpoar if lcft too iong). ihe llvtr,* lrrvrr aro LlIIcd vlLh hot vatcr tad rlro prrtlrvod ln tlcohol for countlnq, Totr] Durbor crposcdr llvllg, rd crrd, erc crtebllrbrd t.plr.t.It for rrtur. (6tu-7tr lartar) and young (tst-5tt tnsta;) l.rvr.. Llrvrr cxporrd to lar.otlcldr rd plprtltG durt4 thr trrt.r. not couutrd crc.pt for th. coDtrol vhrrj thry rrolnoludod ln thr nqrbrr rurrlvlng. Thc urual confonetl0u of r t,.at lr e 113g1 0f 5 conccntrttionr end en untraatod control yltbt'Yo rcpllcrtct lt rrch oouolatrrtlon. Pforat rortrllty ls carculatod rt caoh/iconceatratlon rDd coEo.rF rrrtlon/rortallty llnrr rrtrbllrhod by problt rnalrtl.. lil}{Ex 2 SIXULIUX LARVICIDE SCREEXING IN THE ONCHOCERCI.ASIS CONTROL PROGRAHI{E HET8OD: Rlvcr Trla1 Rivar trial.s lnvolve ftrgt thc aelectlon of a ruitablc !. 5!gg-gSf c.I. brecdlng river, ?1thcr ualI, rcdlur, or lapg3 in a glven reason dependlng on the requi,rerantr end crpectatlons of thc cherlcal. ^ft.t laltlal laboratory scrccnlng. lu ldrquatc rtretch of rlver 1r firat surveyld by hcllcoptrr. Landlngr rrr redc at every potcntlal brccdtag sltc and th. po!1tIve sitrs, (pres.ncc of cggr, Irrvra, pupr.e), rro ldcnLl.flcd ylth colourrd plartlc rtrtps for caricr prospcction rnd vorlflortion.ft.r inractl- cldc trcrtrcnt. ?hc brccdlng rltcr rrc crrcfully rapprd aad rclcvant factort lncludlng torpcrrtup, turbidity and pH of thc vat.r rrG rccordld. The dlrohrr8. of tht rlvcr at or near the polnt of trcatrcnt 1r dctcrrlnrd clthcr by reedlng thc Yater Srugc at thc polnt (if one is availabla), or by rlaeurlng tt vlth r currant retcr or floet. Oace trcatrcnt polnt har bccn chosen tn the partlcular rtretch of the rlycr to bc used, the aEount of forruLatlon rcgulrcd to 5ive the desrred concentratlon for I0 olnutcr of rlver dracharSc ls calculatcd. It 1, usr"lly drluted ulth a convenient atount of rlvor. yeter Jult before appllcatlon. The ectual application uay be carricd out by pouring or yith a haDd prclsuro sprayer ln the casc of saall atroaal. A boat and a prerced drut ray also be used. In these tvo cases, the appllcatlon csn bc tlicd to Iart ]0 o:.nutes. The appltcatlon can also be donc fron the alr uslng a hcllcoptcr. Fron the air, the rnsectlctde rBy be poured through an outlet ln the srdc of th€ rschlDG, or spraycd lnto thc rlvcr using the equiplent uscd 1n routinc operationa. Aarlel appllcation 1s cssentially lnbtantaneous, but thc applicatlon 1s ladc ln slovly- rovlng vatcr aorc dlatancr rbov. th6 first rapldr ln such a lray that th. inlccticidc front tprcads out to glvc I longcr.rpo.ur. ln thc raplda. Evaluatiou of the cffcct of th€ cherlcal on thc lerval strge of the vcctor ir ctrrlcd out 2il hourr or 18 hourr aftrr rppllcatloa. Thr yholc portlon of rlr.r ls agrln survcycd by hclicoptcr and thc proportlon of larya! vhlch havc dctachcd ts cstilatcd. -f A!{X[X 3 CO!{DITIONS AND }fETHODS trOR THE EVALUATION OF THE I}IPACT OT TCX ?AreM TAO;A oF PIRXETHRII 2Ol att. EC (TALCoRD) IPPLIED roR -EM,UIq! Co[TRoL TEST 1 ( in con3unctl.on vlth R83-15) Conccutrrtloa3 0.02 rgll for I0 rln Aoplicatlou rcthod: Ilallcoptcr Location apd d!tG: Hono Rlvcr at Nangbeto (togo) 21 to 22 October, 1983 TEST 2 (ln conJunction vlth R83-18) Concentratlon: 0.015 rgll for 10 rla Apoltcatlou rathod: Bclloopt.r Locatlon and datc; Oban Bour Rlvcr et Brdorr (Toeo) 7 t,o I Dccorbcr, 1983 Rlvcr dlrcharrc t 2.5t)/ *oRivor discharsc t 6.b3/ se c Xrthodr of itrve!tiaatioB: 'I. Slnele sutter placcd in tbe rivcr Thi! Dcthod is bescd on the realureoent of the drlft (d.tachraent) of bcnthlc aquatlc organisr. Thla phenorcnon occurs naturally in a daily cyc1e, but is very ruch incr.aled by thc passage of torlc ratcrialr. Thc gutter (a acctlon of PvC plpe 2r long by 12cr iu dlareter) rcpr€rentr a strctch of ri.ver in riniaturc. It 1r plecGd ln the rlver 2tl hours before the appllcatlon of tnacotlcidc and colonizcd by adding uatural lupport! (stones, graas ctc.) vftn adhcring orgrnlua. It, la usually pleccd a fcu hundred rctrcr belov thc point of application of thG inrcctlcldc. A nat lr attaohcd to tha dornstrcal end of the guttcr, and dctachlng or8sllslt tro collcctcd at lntcrvals eftcr the pas3Bge of the insecticldc. Thls rrthod thus perrltr an analysis of the dynaaics of thc cffcctr of thc inrcctlcldcs, as vcll ac the global raductlon of Gach Sroup of organisrr. 2. Surbcr net catpleg Thc bcuthlc fauna inheblting thc river'bed ir saapled quantitrtlvcly rith a surbcr sarpler boforc and aftcr the pascage of ineecticide. This peruits calculatlon of thc reductlon of the feuns in terrc of organisrs/r2. t