LIBRARY STATE PLANT BOAf?P E-513 September 19UO United States Department of Agriculture Bureau of Entomology and Plant Quarantine MSTHYL BROMIDE FUMIGATION OF THE WHITE-FRINGED BEETLE LARVA IN SMALL FLOWERPOTS IN NEW ORLEANS By E, M. Livingstone, Division of Control Investigations The discovery of the white-fringed "beetle ( Pantomorus leucoloma (Boh.) in New Orleans in the latter part of 1^37 • 9-nd the subsequent promulgation of quarantines by the State of Louisiana and by the Federal Government, under which plant material with soil attached to the roots was not permitted to move from the infested area, made it necessary that experimental work be undertaken to provide means of dis infesting soil masses. The object of the work reported in this paper was to determine the optimum methyl bromide fumigation treatment that might be used with safety on plants grown in this area and to determine the npjcimTam size of flowerpot in the soil of which the treatment would produce complete mortality of whitc-fringod beetle larvae • Method and Proc^ure The insect larvae were collected from infested areas covered with Johnson grass and other weeds in New Orleans and vicinity. These were placed in flowerpots of potting soil conposed of approximately equal parts of brovm river silt, well-rotted cow manure, swanp Icp.fnold, and send or s?Jidy loam; at the sane time wheat or peanuts, sometimes both, were planted in the pots, and when the plants had produced a root system sufficient to bind the soil into -? comp-^.ct npss, they were used in testing the lethal effect of the fumigant on the larvae. The compact mass of soil bound to- gether by the roots simulated the conditions found in pots in which nursery stock is growing. Twenty-four hours after the fumigation the larvae were removed from the soil masses and placed on the surface of moist sand. If they burrowed into the sand, they were counted as having survived the treat- ment; if unable to do so, they were regarded as having been killed by it. The experimental fumigation equipment consisted of a tight metal- lined chamber containing 25 cubic feet of space. The walls were well insulated with bagasse board. In the chamber was a fan for circulating the fumigant ?jid an electric heater operated automatically through a thermostat for control of the temperature during the fumigr'tion treatment. In actual operation the desired number of infested pots of various sizes were placed in the fumigation chamber along with a selection of plants being tested for their ability to withstand the treatment. The heater was then turned on and allowed to operate automatically, a temperature of 85° ^» or slightly above being maintained in all the experiments. Sufficient time was allowed for the soil masses in the pots to reach these temperatures ntp'^ rv-r,ly "by r, c On t i mi^i-s I"'' OD'^r'^t'^ ■^ fan, ni'"' '^t a low ppe«'l t,o r^v^\r\ vriTT' r'nTTir.^o t ": th' r)T^nts, t 'ir oi).?;hoiTt tlr ^-lur^t^on o'*' thp orcfnnig'itins:- hnriting ^~riori grif^ dn.rir.r -^ho fiirpii5''tio'^ oxtiosur'^. 'iH^rn th'^ t-^nTD-^r^tur? f-f th<^ s^il h^'' r-^'^ch'"'^ ''^5° ^' • t^'^ lioui'l n.-thvl bro-ii^- w'>r ii^troHucv'^ on^^ tho fn?"ig^ti">n '^yoopnr'^ '•'''S m'^'^surpf^ frorn this tinr. '^h'' pr'>c'^ol-'^ ■Pnrnignnt ^-'hnut '^'^.5 ■O'^rc'-'nt purr') ws n'J^.Pur-^tl in ^ sr^nll gr'^'^u^t'^i^ cylir'^'^'T on^ intr'^'^uc'^'^ ''in th'' lin^if^. st'^to) through « s-'-al'' opening in th«^ tOTD 0-f th'^ fur.i^^'i'ion ch'^n'hpr. ■^T-oprirr^^rt'^l '^'-Rnlts "■"■n ■» nurih^r -^"^ T3r'^linin=>ry PX"0^rinpnts v«rio\is concPritr''tions '^f n^thyl ■^ro'iido nn'^ v^vi'-^r^s of Px"oosv.r?> vrrre tf=>st'^d for "If^tholity to th- 1 nrvo of thp whit-^-frinrjp'^ h^f^tlr- arid to n-^ryy sppci's of ^Dl^-nts. ^rorn th--S'^ f^x-O'-^rin.^nts it s'^rnp-"' (^.vit^^nt th^^.t th-^ Is-'^pt d.T^%^ to th^^ plants o-f this nr<=fl occurr'^ri vh-'^'n thr corc^ntr^tion of th-'-' funigTit ws low o.nd th° pfTio.^ of pxTJOs^ir^ long, Mh-r^''s high conc'»ntr=«.ti'^ns ^-"'^ sh-^rt '"^y'^OBurns •^Top-^orpd to cusp gr'^"^t--r '^'^m-^gr to plants or g'-ve inconpl'^'t':' r-irt'=ilit:^^ of l^rvo. Cprt^in sps^ci'^s of plants '■N'^re 'norp tolc^rp.nt to thf^' g-^-s th^n othTs. It f'r>^<^!>.rr'r]. th^.t «, rfos^g- of 1 looun'^ of n»thyl iDronido to f^^ch l,'^'^^ cnh ic fo'^t o-^ sp'^cr- in thf cho.n'bf^r ©nr' ^r '^yoosur-'^ of U hours cusi^r? Ip-'st injury in genrrnl to lol^nt lifp, ^nd it vz-^s '^ocir^c-'^ to r^rt'^miin'^ wh^t '•^'^s th'^ l-'.rg'^st sizpd pot of soil in which this dos->ge n.nd "x-oosur^ °t 35° ^* '^^■'^- slightl-" nhovr^ woulcl giv^ « comolf^tr^ r.ort^lity of t'-^st irs'^cts. In t^hli^ 1 ore givn th' r'=sults '^'bt^in^d v/hf^n tho n'^ov- tr^-^tr.ent ws «pDli^^'^ to flowor-oots ?-l/^', ?-l/?., 3- ''nd h inches in sizp. I'h-^ soil ws usu-'lly no nore th-'^.n '^.•oriiura v;^t «"r.d n^^^ver soggv or nucfdy. "^h" r'-'t') giv^n in tp'blf' 1 s^ow th"t " co~>-Dl':^te nort'^lity of l'',r'^''^f in ?-l/U-, P-l/p_, end 3-i^-c5i flower-oots v?ps obt^ln^d. "^hp inort=lity in U-inch -oots w-^s inc'^'^T^lpte »n'^ nvprig^d "^.1 nprcont. It is of int^T'st to mint o^it th-'t thr -^olunp of th^ 2-l/U-inch pot is lO^? cc, th^ ?-l/?- inch pot 1?0 cc, =nd th'^ 3-iiich -not P15 cc. , wh^rpc's th^.t of th^ U-inch pot is ^'^0 cc, which is ?.3 tinps ''s gre^t "^s th« volu»n-^ of th>- 3-i^ch ■not. Sincp th« dPtTninntion th^t l^rva? in thp soil of 3-i"'ch ^nd ?n=llpr flowproots vr^r" ^^'ill'^d hv furig=tion vrith n^^thyl "bronidr 9t » rfos-ag*" of 1 ■Doun'^ for U hours r>t ??5° "^^ ^r slightly ^^hovp. , nurs^^ri-^s in >Tpw Orlp-^ns ©n'^ vicinity hoy--^ funig^t'^d ?ri ■■^stin«>tpd UO thous^ind plants, with thp ''id and sutDorvision of th'^ Louisi^n<» St-^tp "D^-oortr.-^nt of Agriculturp ^nd lTr;T^igriqnts gro'^n cornnorci'^lly in ^^0^1 Orlp^ns v/ill tolpr<^t~ this tr'^atn.pnt, hut a^bout '^ nprcpnt will tol-r^.te it v/ithout noticp^'^lp d^n-^.ge or serious r'^^t^rdation. '''.xprrin''"^^t^l v/ork ^^nd Digitized by the Internet Archive in 2013 http://archive.org/details/methylbromidefumOOunit f^xpprienco in c^^morci*'.! work h^v slnvm th°i.t sn.scr^ptibl'^ plants puffer Irgp cf-^n-'ge wh«n growth is not ^ctivp «»nd thnt n-^wly trsinspl^nt-^?^ rootpd cutting? s».n'^ spof^ling r)l?>nts shoul'l n'^t "bn fmig^tcd until vmll pst«>"b- lish^f^. It follows, th.(=r«forp, th^.t th= tol^r^'nc" of son^ Tal-^nts in thn rlin«>tr o:'' ■^■^'=^w '^rl'^'-'ns to the trp^tnent vari'^s not only with th^^ suoci^'^s on-^ vprii^tv "but with certain p->npwhqt int-^nt^ibl^- conditions of growth, ''/hP'thf^r or not th- larvp of thf* vrhit^-'fringpd "hp-atlp ''ind th'* ol^nts in oth^r ^r^-^s v^h^r^ th'^ "bpptlo is known to occur show thp st.p tol-^r^nco t'"' rprth"! hrori^'- fv.Tnigation th-^t thp?/ do in th° ^T«v; Hrimns r^r'^o ho.s not "hoon ^^ t^'^rTiin"-'^ . '"n'bl'^ 1. — Mortality caused "by m-^thyl trornidp fnnigati'^n to la.rvno i-*^ th'^ whitr-fring?d bpptlp in flowrrpota from P-l/U to k inches in si-'p, vrith 1 pound of funig^^nt to »*>ch 1,000 cubic fpet o^' chj>.inb'"r s'D''ce, for U hours •'t tpr-ppratur^s of ^5° ^* '"^^ slightly qbovp. ITpw Orlp«ns, L^. "^^erips ^Turnber of ^^i^-i-bpr ^f Mort^'.lity of lo.rvn,e No. flovfPrDots l^rvap rp- Funber killod P«='rcent killed covprpd •'ft'^r furtigation L^rvcf.p in 2-1/4- inch flowerpots 1^3 U3 100.0 k k 100-,0 23 P? 100.0 20 20 100.0 31 31 100.0 5 5 100.0 k U 100.0 6 6 100.0 lUl Ibl 100.0 Lorvop in ?-l/?-inch flov;»rpots 3U 3U 100.0 13 13 100.0 31 31 10^.0 IQ 10 lO'^.O U3 U3 100.0 2 2 100.0 P Q 100.0 151 151 100,0 1 13 2 2 3 U 6 I q 1 7 1 5? p 'otol or 'VPr°gp Up Q S 10 3 11 7 12 6 13 10 lU 1 15 3 'otol or ■ verage 3^ LIBRARY STATE PLANT BOARD lb 6 17 3 15? 7 10 5 ^ 10 n 1 ?.?. 1 ?^ 3 ?h 50 P5 1^ p^ 70 ?y U6 ^t'>l or v,-rpgr 220 T'o'ble 1. — contimipd !?pri«^s T^'^im'b^r of ^■^iii^'brr of Nort-'lity of larvop ■^^0. flovorpots l^rve re- Nunb^r killori Percent killed coverort after fiinig.-'ti'^n L^rv^^e in 3-inch flovrerpots 27 27 100.0 12 12 100.0 26 26 100.0 22 22 100.0 U5 Up 100.0 k k 100.0 U U 100.0 11 11 100.0 211 211 100.0 76 76 100.0 2Q5 2^5 100.0 1^0 1^0 100.0 023 ^23 100.0 L-^rvop it^ U-inch floweriDots 56 56 100.0 k U 100.0 51 ^7 02,1 ^7 115 05. 7 3^ 2^ 76.3 7 7 100.0 6 6 100.0 2 2 100.0 237 225 QU.o 20° ■ 20^ 100.0 267 250 03. 6 02U ^80 05 . 1 SunD=iry fi\irnig''.tion of th"^ larvo. of thr whit'^-fring'^d "beetle ^ P-'^ntonorus lencolori"' '''Boh.) in ^'''evr 0rlef»ns with nethyl "bromir^e s»t ^ dosage of 1 pound to .-^och 1,000 cnhic feet of cha.r"b°r sp^ce for n. p'^riod of h hours ^t « tem- TD^rs^-ture of 85** ''''. or '^v«^r=ging closely •^"bov.-^ that point, destroyed infes- t«t ^g thot of th» 3-inch -oot. Ths tre?\tnent h^s "been used successfully in ouar=>ntine work in !ffew Orleans ^md is tolernted "by o.pprox- iriptely ^o pTCont of the pl^^.nt speci'-^s ^nd varietif^s. 2S 6 ?.^ 1 30 6 31 6 32 6 33 1 3^ 1 35 1 3^ 20 3^ 27 3^ 31 Tot^^l or ovoroge 115 UNIVERSITY OF FLORIDA WEWM!