(‘1 IIIIII~ 1(1(* IICYIIIIIC’IIIS to soil arc theIIIO.~I \vI(Ic.Iv IIMYI ;IINI a~~cccssful methodIO ~~I(LI~Y I \voo(k~t~ \IUIC-~LWCS from attack0~ ~s~~l~l~~~ I;III~*;III ((%I riiil(3, and potential-IV ii~‘\\i It.1 iiiilki(l<*s (.oiIIinrte to be placed

III I~IIIIYI %,I \:I( (’ li~4l 1~x1s CYICII year (KardI’J’ULI) ‘l’ll~~‘1~. I(-,(\ t ~IIII~IIIK. IO be installed andIII,IIII~.IIII~~~~ III Ilit. 111 iiii:ii.y I~~iiiilc biology andI(-‘,(-,II~ II ‘,II~Y III AI ~/OII:I, IIwitla, Mississippi(f ,llll~‘tll I) .I1111 S~~lllll (‘;ll~olill;l.

A ~,III’ 11~1s~ IHY.II c*\l:ll)li\llc~tl iI1 Puerto Rico forIIIIIII(* I(YI~, III ON. 1101)ic.s, ;III(I specialized tests\~~illi ii011 c li(.iiii~ ;(I l~livsic-;il Ixii-riers are beingt 41111lii( 1~31 III 111~. I(c~luilAic.01~ Pallama, as well asAI (IIII I’III IIIOL).III VII)IC.I I:IIKYIII rcscarch site onMII~w,I\, 14.11~1. (‘OIII~IIII~II): I;orcst Scrvicc fieldIC~.IIIII: \\:IIII c.\I\I~II~: ;IIKI ~~;llltlitlate termiticidcs,IIOII ( IU’IIIII (11 ILII I it.1 5;. IIOII rc~l)c.llent termiticidesiiiicl O,iil., IVIII c ~II~~IIII~~ lo ~~i~ovi~lc vital informa-(ioIl IO III{. IN-J c OIIII.O~ i1~111s1t.y IOr the foresec-,llll~~ lllll1l~’

1~~i.11 1c.1 iiiili~~i~l~~s :II.C’ c.iii.i.c~iltly registeredII\ 1111. I,II\,IIIIIIIII(‘III;II I’rot(x‘lioll Agency (EPA)(01 iix* iiii(lk.i .iii(l ;II~~IIII~~ wootlcn structures,+iii(l \vilI ( 011liiiii(~ lo ~)I;i,y ;III iii1portant role inICI IIIIICS III~III.IJ’(‘III(‘III. Atltliliolrally, cylluthrin andIII-II.IIII~-IIII III II;IV(* II(Y*II (*II’cc.Iivc in field tests forIIIOIV IILIII IIVC. VCXII‘S, 1~11 ;II.C IIOI yet available toll(“,l t 0IIlI0l O,N’I ;llol~s (I’(:os).

I’IC*IIIIV. c OIII~~I~~I(YI livcx ~CY~I-S of field tests inI’J’j/, w11l1 ICYIIII\ I~C~~NW~CYI itI 111~. April 1998

issue of Pest Con~ro2 magazine (Kard 1998b). Six-year Premise results will be provided in a scpa-rate Pest Control article during 1999.

Termiticides are evaluated in field applica-tions using scvcral different concentrations.These Forest Service tests determine the year-s-of-effectiveness of currently marketed andpotentially new ter,miticides as treatments to soilunder long-term field conditions. Results areprovided to the EPA as part of the registrationprocess.

The ability of subterranean termites to pcne-trate termiticide-treated soil to attack pineblocks or boards is evaluated for at least fiveyears, but tests often last much longer. Yearlyevaluations continue for as long as a termiticideremains an effective barrier. However, when tel.-mites penetrate treated soil and attack the woodin 50 percent or more of the replicates of a par-ticular treatment, that treatment is no longerevaluated at that test site. Results of field teststhrough the end of 1998 are provided in theaccompanying table.

In standard grotmd-board and concrete-slabtests in the United States, termiticides providedvarying years of subterranean termite control,depending on concentrations applied to the soiland test site location. Years of 100 percent con-trol (as of November 1998) provided by each cur-rently marketed termiticide active ingredient,applied at highest label rates under concreteslabs in the four primary test sites, include thefol lowing.

l chlorpyrifos 1 .O percent (Dursban TC,Equity, Tenure, Cyr,ene, Navigator), six to 12years (197 1 four-site test), 2 1 years (1967Mississippi test);

l cypermethrin 0.5 percent (Demon TC,Prevail FT), four to 12 years;

l permethrin 1 .O percent (Dragnet FT), five to

15 years, (Torpedo, Prelude), three tomore than 18 years;

l fenvalerate 1.0 percent (Tribute),six to 12 years; and

l bifenthrin 0.125 percent (Talstar,Biflex TC), two to more than 12years.

Cyfluthrin (Tempo 2 TC) at 0.5percent has been 100 percenteffective for more than 11 years,the length of this test to date.Deltamethrin EC at 0.125 percent(DeltaGard TC) has provided four tomore than 10 years of 100 percentcontrol, and should last longer at the0.25 percent concentration. AgrEvo

at least one concrete-slab and oneground-board application of eachconcentration, for a minimum of 10replicates of each treatment at eachtest site.

The concrete-slab method simu-lates a poured concrete foundation.To establish a test plot, leaves anddebris are removed to expose soil ina square area 24 inches on a side. A2 l-inch-square wooden frame con-structed of one-inch-by-one-inchspruce strips is placed in the centerof the cleared area, and a triangulartrench two inches deep and two

Environmental Health plans to mar-ket DeltaGard TC as a suspensionconcentrate with a planned generaluse rate of 0.125 percent, and at 0.25percent for use in difficult-to-treatsituations.

When installing termiticide fieldtests, an experimental area is estab-lished that contains 10 blocks of land(each 35 feet by 35 feet), with eachblock subdivided into 49 plots (eachfive feet by five feet). Each termiti-tide treatment is replicated once ineach block (one treatment per plot)in a randomized complete-blockdesign.

Termiticides are evaluated usingboth ground-board and concrete-slabmethods (Beal 1980; Beal et al.1994). Standard water mixtures oftermiticides are applied to the soil atseveral active ingredient concentra-tions, usually ranging from 0.00 per-cent (water-only controls) to 1 .O per-cent by weight, at pre-constructionvohtmes. Each block of land contains

inches wide at the top is dugaround the inside of and adjacentto the frame.

A square metal frame, 17 incheson a side by four inches high, is thencentered within the wooden frame,and termiticide is applied evenly tothe soil surface within the metalframe. The metal frame is removed,and a vapor barrier (six-m&thick,2 1 -inch-square plastic sheet) isplaced over the treated area. A seven-inch-tall PVC plastic pipe, fourinches in diameter, is placed uprightat the center of the vapor barrier, andconcrete is poured over the vaporbarrier until it reaches the top of thewooden frame. The concrete is fin-ished with a trowel, resulting in asmooth-surfaced slab.

After the concrete hardens, thevapor barrier at the bottom of thePVC pipe is cut out to expose treatedsoil. Care is taken not to disturb thetreated soil when removing the circu-lar piece of vapor barrier. A two-by-three-by-four-inch pine-sapwoodblock is placed inside the pipe and

directly on the treated soil. The PVCpipe is capped to reduce loss of mois-ture and to preclude rain and sun-light from affecting the termiticide.

The ground-board method is simi-lar to the concrete-slab method,except that no concrete slab or vaporbarrier is used. A one-by-six-by-six-inch pine-sapwood board is placedon the termiticide-treated soil andweighted down with a brick. Thetreated area remains exposed toweathering. Decayed blocks andboards are replaced during annualevaluations.

The following examples help inter-pret the table.

In Mississippi, 1 .O percent fen-valerate placed under concrete slabsin 1978 provided 100 percent controlof subterranean termites for 10years. Control then declined to 90percent during the 1 lth year, whereit remained for one year beforedeclining further to 70 percent. Itremained at 70 percent for two yearsbefore falling to 60 percent effective-ness, where it remained for twomore years. By the next year, itdeclined to 50 percent.

In South Carolina, 1 .O percentpermethrin (Torpedo) under con-crete slabs was 100 percent effectivein preventing penetration of subter-ranean termites through treated soilfor six years. Control then declinedto 90 percent during the seventhyear, where it remained for one yearbefore declining further to 80 per-cent. It remained at 80 percent fortwo years before declining to 70 per-cent, where it remained for one year.The next year, it declined to 60 per-cent, where it remained for two yearsbefore declining to 50 percent, whereit remained for at least one year.

The asterisk (*) after the “1”indicates that evaluation of thistreatment stopped after one year at50 percent. Thus, the total numberof years that 1 .O percent permethrin(Torpedo) remained at 50 percent

control was not recorded. Otherasterisks found in the table indicatethe same situation. Arrows betweendifferent percentage-of-effective-ness levels represent a greater-than-lo-percent loss in termite controlsince the previous evaluation. Adash in the table represents termitecontrol percentages not yetobserved.

The table indicates that termiti-tide field tests are installed duringdifferent years. Thus, a termiticidereported as 100 percent effective fora specific number of years is not nec-

essarily less successful than onereported as 100 percent effective fora longer period. The periods of test-ing are simply different.

It should be recognized that, toachieve termite control for the num-ber of years indicated by researchresults using currently marketed ter-miticides, there is a narrow marginof safety for creating an effective bar-rier in the soil. For termiticides to beeffective for as long as possible, theymust be applied as a continuous bar-rier in the soil, preferably at theirhighest label rates. PCOs will need to

invest more time with clients toexplain the important benefits andactual costs of providing a qualitytermiticide service.

Brad Kard is a principal researche n t o m o l o g i s t a t t h e U n i t e d S t a t e sDepartment of Agriculture’s Forest Service,Mississippi State, Miss.

Beal, R.H. 1980 New materials for iermife control. Pest Control 48(11) ,46-54.

Bea/, R. H.. 1.K Mao/din and SC. Jones. 1994. Subterraneantermites-their prevention and conlrol in buildings. Home andGarden BUN MO. 64, Forest Service-USDA, Washington, D.C.

Kard. 6 M. 1998a Termm,bode Field Tests Continue Moving ForwardPest Conirol66(2):42-44.

Kard, 8 . M 19986. Premise Termiticide Field Test Resok Pest Control66(4):64-65,105

OReprinted f r o m P E S T C O N T R O L , F e b r u a r y 1 9 9 9 A N ADVANSZAR @J P U B L I C A T I O N P r i n t e d i n U . S . A .

The use of trade or firm names in this publication ISfor reader information and does not implyendorsement by the U.S. Department of Agrkuttureof any product or service.