COMMODITY TRETMENT ND QURNTINE ENTOMOLOGY Testing its to rgentine nts (Hymenopter: Formicide) in Vineyrds KENT M. DNE,, MONIC L. COOPER, KREN R. SIME, ERIK H. NELSON, MRK C. TTNY, ND MICHEL K. RUST J. Econ. Entomol. (): 699Ð79 (8) STRCT its were evluted for control of the rgentine nt, Linepithem humile (Myr) (Hymenopter: Formicide), nd ssocited melyug nd soft scle pests in Cliforni vineyrds. In, liquid its with smll doses of imidcloprid, oric cid, or thimethoxm dissolved in % sucrose wter resulted in lower nt nd melyug densities nd fruit dmge, compred with n untreted control. Similr tretments in soft scle-infested vineyrd showed only reduction of nt density nd fruit infesttion in only the oric cid nd thimethoxm tretments. In, commercil nd noncommercil formultions of liquid its reduced nt densities in three seprte trils, ut they hd inconsistent effects on melyug densities nd fruit infesttion; grnulr protein it hd no effect. Using lrge plots nd commercil ppliction methodologies, liquid it deployed in June resulted in lower nt density nd fruit infesttion, ut it hd no effect on melyug density. cross ll trils, liquid it tretments resulted in lower nt density ( of trils) nd fruit dmge ( of sites), presenting the Þrst report of liquid its pplied using commercil methodologies tht resulted in reduction of nts nd their ssocited hemiptern crop dmge. For commerciliztion of liquid its, we showed tht ny of the tested insecticides cn suppress rgentine nts when properly delivered in the crop system. For imidcloprid, it dispensers must e protected from sunlight to reduce photodegrdtion. Results suggest tht incomplete nt suppression cn suppress melyug densities. However, fter nt popultions re suppressed, there my e longer period efore hemiptern popultions re effectively suppressed. Therefore, liquid its should e considered prt of multiseson progrm rther thn direct, in-seson control of hemiptern pest popultions. KEY WORDS rgentine nt, Linepithem humile, Pseudococcide, liquid its, vineyrds The rgentine nt, Linepithem humile (Myr) (Hymenopter: Formicide), is n invsive species tht hs estlished over wide geogrphic rnge, often with dmging economic nd ecologicl effects (Holwy et l. ). lthough commonly recognized s n urn pest (Rust nd Knight 99), the rgentine nt lso hs dverse impcts in nturl nd griculturl systems. In most introduced regions, its unicolonil nest structure, low genetic diversity, high popultion density, nd efþcient use of resources cn provide competitive dvntge over other nt species (Chen nd Noncs, Tsutsui et l. ). s result, rgentine nts often displce ntive nts, nd their presence cn disrupt other invertertes nd even verterte nd plnt popultions (Snders et l., Surez et l. ). In griculturl systems, rgentine nts re ssocited with outreks of phloem-feeding Deprtment of Environmentl Science, Policy nd Mngement, University of Cliforni, erkeley, C 97-. Corresponding uthor, e-mil: dne@uckc.edu. University of Cliforni Coopertive Extension, Sn Luis Oispo County, 6 Sierr Wy, Sn Luis Oispo, C 9. Deprtment of Entomology, University of Cliforni, Riverside, C 9. hemipterns, which they tend nd protect from nturl enemies in return for honeydew, nutrient-rich food source (uckley nd Gulln 99). In CliforniÕs costl wine vineyrds, the rgentine nt hs een implicted in outreks of the grpe melyug, Pseudococcus mritimus (Ehrhorn), nd the oscure melyug, Pseudococcus viurni (Signoret) (Dne et l. 7). Melyugs infest fruit clusters nd dmge the vine y shunting photosynthtes from the phloem nd y excreting honeydew, which promotes the growth of sooty molds tht further inhiit photosynthesis. Melyugs lso cn lower crop vlue y trnsmitting closteroviruses (Golino et l. 999.). rgentine nts lso tend soft scles (uckley nd Gulln 99), nd they my e ssocited with incresing prolems with Europen fruit lecnium, Prthenolecnium corni (ouché), in vineyrds. Exclusion experiments using sticky rriers on the vine trunk hve shown tht complete removl of rgentine nts cn lower oth grpe nd oscure melyug densities nd their crop dmge (Dne et l. 7). However, commercil use of sticky rriers to exclude nts in Cliforni vineyrds is imprcticl ecuse of high ppliction costs. In lieu of commercilly -9/8/699Ð79$./ 8 Entomologicl Society of meric
7 JOURNL OF ECONOMIC ENTOMOLOGY Vol., no. effective culturl or iologicl controls, reserch hs insted focused on insecticides. Historiclly, rgentine nt control hs relied on contct insecticides tht ct s rrier tretments (Rust ; Klotz et l., ). These sprys provide only prtil suppression: lthough they kill forgers, they hve little or no effect on the queens nd rood in the nest (Knight nd Rust 99). Forgers constitute only smll frction of the workforce, nd they re quickly replced y nestmtes tht mture during the tretment period. nother drwck of the chemicl rriers is tht they commonly degrde within d, incresing the need for repeted pplictions (Rust et l. 996). Continerized nt its present severl dvntges over trditionl rrier sprys. First, its exploit nt forging nd socil ehviors s scouts recruit nestmtes to it sttions (Silvermn nd Roulston ). rgentine nts use persistent tril pheromones to orient colony memers to food resources, resulting in Þdelity to it sttion loctions (Veg nd Rust ). ecuse it is exchnged mong colony memers (including lrve nd queens) vi trophllxis (Knight nd Rust 99), its hve the potentil to provide seson-long control, rther thn temporry reduction of forgers. its lso reduce undesirle environmentl impcts, ecuse only smll mount of insecticide is plced in the Þeld (Tniguchi et l. ). nt its re prepred in two min forms: grnulr (dry) protein or soyen oil its, nd liquid sucrose-sed its. The grnulr its hve een shown to e effective ginst Þre nts nd other myrmicine nts in vrious systems, including nursery (Cost et l. ), forest (Krushelnycky nd Reimer 998), urn (lchly nd Forschler 996, Klotz et l. ), nd griculture (Tniguchi et l., Tollerup et l. ). However, they re not highly ttrctive to rgentine nts (ker et l. 98, Klotz et l. ), whose diet consists minly of sugrs. For exmple, 99% of the mteril crried to the nest y rgentine nts forging on citrus trees ws either citrus nectr or honeydew produced y the citrus melyug, Plnococcus citri (Risso) (Mrkin 97). This preference required the development of liquid, crohydrte its for rgentine nt control (Silvermn nd Roulston, Rust et l. ). We previously demonstrted tht liquid its with low dose of thimethoxm (.%) cn reduce rgentine nt densities in Cliforni vineyrds nd tht this reduction results in suppression of melyugs nd their crop dmge (Dne et l. 6). Here, we report on continued reserch towrd the development of n nt control progrm for vineyrds, with the speciþc gol of testing insecticide mterils nd using ppliction techniques tht might e suitle for commercil opertions. Mterils nd Methods Field Sites. Experiments were conducted in CliforniÕs North Cost nd Centrl Cost wine grpe regions. ll vineyrds hd popultions of rgentine nts nd ssocited hemiptern pests. The North Cost vineyrds were infested with either the grpe melyug or the Europen fruit lecnium scle. The Centrl Cost vineyrds were infested with the oscure melyug. ll vineyrds were mture ( 8 yr old), on dripline irrigtion systems, nd with vine spcings tht resulted in,8ð, vines per h. Vineyrd ßoors were cover cropped in lternte row middles (Centrl Cost) or ll row middles (North Cost). hericide (glyphoste) ws pplied for weed mngement within rows. During the experiment, no insecticides were used (other thn the pplied tretments), ut sterol inhiitors nd/or sulfur were pplied to control powdery mildew (Uncinul nector urrill). Insect Smpling. nt densities were determined y mesurement of feeding ctivity, ssessed s the mount of nontoxic sucrose wter removed from -ml polypropylene centrifuge tues (Corning Inc., Corning, NY) tied to the vine trunk (Klotz et l. ). The -ml tues re henceforth referred to s monitoring tues. -cm hole ws drilled in the cp, nd squre of permele plstic mesh (Weedlock, Esy Grdener Inc., Wco, TX), ws plced etween the cp nd the Þlled tue, covering the hole. The mesh ws Þne enough to retin the liquid when the tue ws inverted, ut it ws corse enough to llow nts to remove the liquid on contct. The monitoring tues were Þlled to ml with % sucrose wter, weighed, nd inverted on vine trunk for Ð7 h (depending on nt ctivity). They were then rought ck to the lortory nd reweighed. One dditionl monitoring tue per plot ws ttched to n nt-excluded moo stke to mesure the mount of wter lost to evportion, which ws verged cross ll plots nd used to djust the Þnl weight. ecuse ech milliliter of sugr wter emptied from the monitoring tue represents, nt visits (Veg nd Rust ), sugr wter removl rtes re relted to nt density. Melyugs nd Europen fruit lecnium scle were monitored using timed visul serches, sed on methods developed y Geiger nd Dne (). Rndomly selected vines were serched for. or min ech, nd the numers of second instr to dult stge melyugs or scles were recorded. n experienced smpler could determine tht prt of vine where these pests were most likely to occur t given time of yer, which llowed djustment for sesonl chnges in their distriution on the vine. rk on the trunk, cordon, nd spurs ws stripped wy when necessry. ecuse the visul serch ws destructive process, individul vines were smpled only once during the seson. To ssess crop dmge t hrvest time, vines were rndomly selected within ech plot, nd three fruit clusters from ech of the selected vines were rted t hrvest on Ð scle, where represents no melyugs; indictes presence of honeydew nd/or melyugs; represents melyugs, sooty mold, nd/or honeydew; nd indictes hevily infested, unmrketle clusters. Fruit clusters in direct contct with woody prts of the vine were preferentilly smpled, when ville, ecuse such clusters re more likely to e infested with melyugs (Geiger nd Dne ). Fruit dmge levels ddress economic
June 8 DNE ET L.: RGENTINE NT CONTROL IN VINEYRDS 7 dmge, nd they my lso e etter ssessment of melyug density thn the timed melyug counts ecuse more vines could e smpled during the sme period. For ech smpling method used, the smpling frequency nd numer of vines smpled re provided for ech experimentl tril. it Dispensers. The it dispensers were mde from -ml polypropylene centrifuge tues (Corning Inc.). They were Þlled to ml with it solution, nd they were deployed on the vine s descried ove for the monitoring tues. The tues were clened nd reþlled every Ð wk throughout ech experiment. In experiments, modiþctions to the it dispenser were mde for two insecticide mterils. First, we suspected tht imidcloprid ws susceptile to photodegrdtion in the it dispensers; the tretments with imidcloprid were shielded with Styrofom continers ( y 7 y 7 cm) (merifoods Trding Co., Los ngeles, C). The it dispensers Þt inside the continers, wheres the cp remined exposed to llow nts to feed. Second, when testing grnulr spinosd, pellets were loded into it dispensers tht were then deployed horizontlly on the vine nd without the plstic mesh, llowing ntsõ ccess to the grnulr it. Experiment : ctive Ingredients. In, the effectiveness of three ctive ingredients nd n untreted control were tested. ctive ingredients were.% crystlline oric cid (Fisher Chemicls, Fir Lwn, NJ),.% imidcloprid (yer Crop- Science, Knss City, MO), nd.% thimethoxm (Syngent Crop Protection, Richmond, C). ll of the percentges re weight to volume in wter, nd ech chemicl ws technicl grde mteril. The it/food ws % sucrose wter. oric cid ws mixed directly into sucrose wter; thimethoxm nd imidcloprid were Þrst dissolved in Ð ml of ethnol, nd then they were mixed into the sucrose wter (Ð liters). Dilute quntities of ethnol hve no effect on the consumption of sucrose wter y rgentine nts (ker et l. 98). Experiments were conducted in two independent sites: Np Vlley ppelltion Chrdonny vineyrd (8. h) (8.68 N, 8.7 W) infested with the Europen fruit lecnium scle nd n Edn Vlley ppelltion Chrdonny vineyrd ( h) ( 8. N,.8 W) infested with the oscure melyug. The four tretments were estlished in rndomized complete lock design, with four replictes per tretment t ech site. Ech replicte ws vine plot (Þve rows vines); row/vine spcing ws..8 m ( vines per h) nd..8 m (79 vines per h), respectively, for the Np nd Edn Vlley plots. Neighoring replictes were seprted y Þve row uffers (no plots were within the sme rows). The it dispensers were deployed on 7 nd pril t Edn Vlley nd Np Vlley ppelltion vineyrds, respectively, t density equivlent to dispensers per h. nt density ws mesured t -wk intervls, from Jnury through Octoer, y using 7 monitoring tues nd one evportion tue per replicte. Scle or melyug counts were mde pproximtely every d, from Ferury to Octoer, on rndomly selected vines per replicte, selected from the middle rows of ech plot. Crop dmge ws evluted t the Np Vlley site on 6 Septemer, y using vines per replicte (% of the vines), nd t the Edn Vlley site on Octoer, y using vines per replicte (6% of the vines). Experiment : Commercil nd Novel Formultions. In, tretments were ) commercil nt it of.% imidcloprid, delivered in liquid sucrose solution (Pre-Empt, yer CropScience); ) commercil nt it of.% spinosd, delivered in grnulr it (Justice, Dow grosciences, Indinpolis, IN); ) noncommercil formultion of.% spinosd (technicl grde, Dow grosciences), delivered in liquid sucrose it; nd ) n untreted control. Pre-Empt ws tested using n experimentl use permit s it ws registered for urn ut not griculturl use; yer CropScience is currently mrketing Vitis (.% imidcloprid) for commercil use in vineyrds. Three independent experiment sites were estlished: Sonom Pinot Noir vineyrd (. h) (8.7 N, 6. W), Snt Mri Gewürztrminer vineyrd (.8 h) ( 8. N, 6 9.96 W), nd Snt Mri ppelltion Chrdonny vineyrd (9.7 h) ( 7.98 N,.6 W). t ech site, the four tretments were set in rndomized complete lock design with three replictes. Ech replicte ws n 8 vine plot (four rows vines); row/vine spcing ws..8 m (79 vines per h) t the Sonom nd Snt Mri Gewürztrminer sites, nd.66. m (,8 vines per h) t the Snt Mri Chrdonny site. There were Þve-row uffers etween ech replicte. it sttions were deployed t rte of per plot, which ws equivlent to 6 nd per h (,8 nd,79 vines per h, respectively), on pril (Pinot Noir), Mrch (Gewürztrminer), nd pril (Chrdonny). nt density ws monitored pproximtely every d from pril through Octoer, y using monitoring tues nd one evportion tue per replicte. Timed melyug counts were mde pproximtely every d on Þve vines per replicte. Crop dmge ws evluted on eight vines per replicte (% of the vines) on 6 ugust (Pinot Noir) nd nd Septemer (Gewürztrminer nd Chrdonny, respectively). Experiment : Imidcloprid in Lrge Plots. In, n experiment ws conducted to determine the effect of plcing fewer nt its over lrger re. This experiment ddressed our concerns tht there ws too much nt movement etween tretments in experiments using smller plots (e.g., four rows vines, Þve-row uffers) nd tht the it sttion deployment rte (e.g., up to per h) ws not commercilly fesile. This experiment used rndomized complete lock design with two plots in ech of Þve locks. Ech lock ws locted in different vineyrd, ech infested with rgentine nts nd oscure melyugs. The minimum distnce etween vineyrds ws km.
7 JOURNL OF ECONOMIC ENTOMOLOGY Vol., no. The tretments (it nd control) were ssigned to the two plots in ech lock; the minimum distnce seprting the plots ws m. it sttions were Þlled with.% imidcloprid in % sucrose wter nd deployed t density of per h, spced evenly throughout ech plot. it plots were reltively lrge ( rows vines to rows 6 vines, or.ð. h ech), wheres the control plots were smller (Þve rows vines,. h) to ccommodte the collorting vineyrd mngersõ concern tht limited re would e plced t risk without ny nt or melyug controls. res outside of the it nd control plots were treted s needed with insecticides. The ppelltion, cultivr, nd it sttion deployment periods in the Þve vineyrds were s follows: Snt Ynez ppelltion Chrdonny lock ( 8. N, 8 9. W) with its deployed on 8 My, Snt Mri Gewürztrminer lock ( 8. N, 6 9.96 W) with its deployed on My, two Snt Mri ppelltion Chrdonny locks ( 7.98 N,.6 W) with its deployed on 6 nd 7 June, nd n Edn Vlley ppelltion Chrdonny lock (. N, 6.87 W) with its deployed on July. nt density ws monitored three times during the growing seson (July, ugust, nd Septemer), y using 8 monitoring tues nd one evportion tue per replicte. Timed melyug counts were tken three times (prehrvest counts, Ð July nd Ð8 ugust nd posthrvest counts, SeptemerÐ6 Octoer) on nd rndomly selected vines per plot in the it nd control tretments, respectively. The difference in smple dtes reßected the logistics of smpling geogrphiclly seprted plots nd differences in vine phenology; the difference in the numer of smpled vines reßected differences in plot sizes. Crop dmge ws evluted etween Septemer nd Octoer, on % of the vines per tretment plot. Experiment : Thimethoxm it nd Sticky rriers. In, n experiment ws conducted to compre the effects of nt suppression using liquid it versus complete nt exclusion. The vineyrd ws.7-h Pinot Noir lock in the Crneros ppelltion (8 9.9 N,.8 W) tht ws infested with the grpe melyug; the experimentl re ws vines 8 rows divided into eight plots. Plots were vines rows, with Þve row uffers etween plots; row/vine spcing ws. m.8 m ( vines per h). Tretments were liquid it (.% thimethoxm) in % sucrose wter nd ununtreted control. it nd control tretments were set in rndomized complete lock design, with four replictes. Within ech of the it tretment plots, Þve nt-excluded vines were estlished ( totl). To exclude nts, shoots were pruned ck from djcent vines to isolte the vine nd the trellis-wires, nd the se of the trunks ws swed with Stikem resin (Seright Lortories, Emeryville, C). The sticky rriers were checked every wk from My through Septemer, nd the Stikem rriers were repplied s needed. it dispensers were dispersed t vine intervls, which ws equivlent to tues per h, nd they were deployed 7 Jnury. nt feeding ctivity ws monitored every wk using monitoring tues nd one evportion tue per replicte. nt monitoring tues were not plced on the exclusion vines, ut insted visul count of ll nts moving pst Þxed point on the vine trunk ws mde during -s period every Ð wk, from Mrch to Octoer. Timed melyug counts were mde every wk, from Ferury to Octoer, on rndomly selected vines per replicte. The exclusion vines could not e repetedly smpled using the timed counts ecuse of the destructive nture of the procedure; thus, they were smpled only once, fter hrvest. Crop dmge ws evluted on Septemer on vines per plot (% of the vines), nd on ll the exclusion vines. Sttistics. Results re presented s mens per tretment ( SEM). Seson-long tretment effects on insect densities were determined using generl liner model. The model used nt feeding ctivity (grms of sucrose wter removed per dy) or timed visul counts (insects per vine per timed count) s function of tretment, smple dte, nd tretment smple dte interction. Smple dte ws set s ctegoricl vrile to exclude its effect on tretment. If the tretment smple dte interction term is not signiþcnt (P.), this nlysis is equivlent to n nlysis of covrince with smple dte s the covrite. For ll nlyses, the verge per replicte ws used s the smple unit. Dt were trnsformed (log[x ]) s needed to stilize the vrince. Results of the generl liner model re summrized in ppendix nd. When there ws tretment effect, tretments were seprted using SchefféÕs test; the pirwise comprisons re discussed in the text. For fruit dmge rtings the tretment effects were compred using contingency tles (Systt Softwre, Inc. 7). For ll experiments with three or more tretments, pirwise comprisons (tretment dmge rtings) were mde for ll possile tretment comintions, with n experiment-wide error rte t./n, where n is the numer of possile pirwise comprisons. Results Experiment : ctive Ingredients. Seson-long nt density differed mong tretments t the Np Vlley site (Fig. ); pirwise comprisons showed less sucrose removed (lower nt density) from monitoring tues in the oric cid thn control nd imidcloprid tretments (P. nd P., respectively). nt density in the thimethoxm tretment ws lso lower thn in the control nd imidcloprid tretments (P. nd P.9, respectively). There ws no difference etween oric cid nd thimethoxm (P.98) or etween the control nd imidcloprid (P.9) tretments. There ws no tretment effect on seson-long Europen fruit lecnium densities (F.9, df, P.). Fruit dmge, however, corresponded closer to nt density, with lower rtings in the oric cid nd thimethoxm tretments compred with the control,
June 8 DNE ET L.: RGENTINE NT CONTROL IN VINEYRDS 7 Sugr wter removed (g / dy) Fruit dmge y ctegory (%) oric cid () Thimethoxm () Imidcloprid () Jn Fe Mr pr My Jun Jul ug Sept Oct Nov Dec 8 6 oric cid Thimeth. wheres the imidcloprid ws not different from other tretments (Fig. ). t the Edn Vlley site, nt densities were lower in the oric cid, thimethoxm, nd imidcloprid tretments compred with the control (P. for ech comprison). nt density in the oric cid tretment ws not different from either thimethoxm or imidcloprid (P.986 nd P.999, respectively), nor ws there difference etween thimethoxm nd imidcloprid (P.96) (Fig. ). Similr to nt densities, melyug densities in the oric cid, thimethoxm, nd imidcloprid tretments were significntly lower thn in the control (P., P.9, P., respectively) (Fig. ). There were no other tretment effects on melyug densities (pirwise comprisons of oric cid versus thimethoxm nd imidcloprid were P.7 nd P. 87, respectively, nd thimethoxm versus imidcloprid ws P.998). Fruit dmge rtings were lower in ll it tretments thn in the control, nd were Imidclo. Dmge rtings Fig.. nt feeding ctivity () nd fruit dmge () in Np Vlley ppelltion vineyrd, infested with Europen fruit lecnium scle, from experiment compring liquid its with different ctive ingredients. rrow indictes when its were Þrst deployed. Tle provides the generl liner model for nt feeding ctivity nd pirwise comprisons re provided in the text. Fruit dmge rtings differed mong tretments (., df, P.7); pirwise comprisons (df,.) re s follows: control versus oric cid: 6.7, P.9; control versus imidcloprid:.8, P.6; control versus thimethoxm: 8., P.; oric cid versus imidcloprid:.6, P.; oric cid versus thimethoxm:.96, P.769; nd imidcloprid versus thimethoxm:., P.689. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments. Sugr wter removed (g / dy) Melyugs / vine / min count Fruit dmge y ctegory (%) 8 6 8 6 oric cid () Thimethoxm () Imidcloprid () Jn Fe Mr pr My Jun Jul ug Sept Oct Nov Dec oric cid () Thimethoxm () Imidcloprid () Jn Fe Mr pr My Jun Jul ug Sept Oct Nov Dec oric cid Thimeth. Imidclo. C lower in the oric cid thn in the imidcloprid tretment (Fig. C). Experiment : Commercil Formultions. t the Sonom Vlley vineyrd, nt densities in plots with liquid formultions of imidcloprid nd spinosd were lower thn those in the grnulr spinosd nd control tretments (P., for ech comprison), wheres there ws no difference etween the liquid imidclo- c Dmge rtings Fig.. nt density (), melyug density (), nd fruit dmge (C) in n Edn Vlley ppelltion vineyrd, infested with oscure melyug, from experiment compring liquid its with different ctive ingredients. rrow indictes when its were Þrst deployed. For nt nd melyug densities, the generl liner model output is provided in ppendix, nd pirwise comprisons re provided in the text. Fruit dmge rtings differed mong tretments ( 99.7, df 9, P.); pirwise comprisons (df,.) re s follows: oric cid versus thimethoxm, imidcloprid, control:.6, P.6;.7, P.; 6., P.; thimethoxm versus imidcloprid nd control:.8, P. nd 8.6, P., respectively; nd imidcloprid versus control: 7., P.. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments.
7 JOURNL OF ECONOMIC ENTOMOLOGY Vol., no. Sugr wter removed (g / dy) Melyugs / vine / min count Fruit dmge y ctegory (%) 8 6 8 6 imidcloprid () spinosd () Grnulr spinosd () imidcloprid spinosd Grnulr spinosd Mr pr My Jun Jul ug Sept Oct Nov imidcloprid () spinosd () Grnulr spinosd () Mr pr My Jun Jul ug Sept Oct Nov C Dmge rtings Fig.. nt density (), melyug density (), nd fruit dmge (C) in Sonom ppelltion vineyrd, infested with grpe melyug, from experiment compring liquid formultions of imidcloprid nd spinosd, grnulr formultion of spinosd, nd n untreted control. rrow indictes when its were Þrst deployed. For nt nd melyug densities, the generl liner model output is provided in ppendix, nd pirwise comprisons re provided in the text. Fruit dmge rtings differed mong tretments ( 9.7, df 9, P.); pirwise comprisons (df,.) re s follows: liquid imidcloprid versus liquid spinosd, grnulr spinosd, nd control:.99, P.8;., P.;., P., respectively; liquid spinosd versus grnulr spinosd nd control:.7, P.6 nd.6, P., respectively; nd grnulr spinosd versus control:.8, P.7. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments. prid nd spinosd (P.7) or grnulr spinosd nd control (P.998) tretments (Fig. ). Melyug density showed similr pttern, with lower counts in liquid formultions of imidcloprid nd spinosd thn the control (P.7 nd P., respectively) nd the grnulr spinosd (P.8 nd P., respectively) tretments, nd no difference etween the liquid formultions of imidcloprid nd spinosd (P.8) or the grnulr spinosd nd control (P.997) tretments (Fig. ). Tretment effect on fruit dmge followed slightly different pttern, with lower dmge in the liquid imidcloprid thn in oth the control nd grnulr spinosd tretments, ut no difference etween liquid spinosd nd the other tretments (Fig. C). t the Snt Mri Gewürztrminer vineyrd, nt densities were lower in liquid formultions of imidcloprid nd spinosd thn in the grnulr spinosd nd control tretments (P. for ll pirwise comprisons), wheres there ws no difference etween the two liquid formultions (P.78) or etween the grnulr spinosd nd control (P.969) tretments (Fig. ). Melyug densities followed different pttern, with lower counts only in tretments with liquid formultions of imidcloprid nd spinosd compred with the grnulr spinosd (P.8 nd P., respectively), wheres ll other pirwise comprisons showed no tretment effect (control versus liquid imidcloprid, liquid spinosd, nd grnulr spinosd were P.679, P.7, nd P., respectively; liquid formultions of imidcloprid versus spinosd ws P.999) (Fig. ). Fruit dmge ws lower in the liquid imidcloprid thn the grnulr spinosd nd control tretments; there were no other sttisticlly signiþcnt pirwise comprisons (Fig. C). t the Snt Mri Chrdonny vineyrd, there were few tretment effects. nt density ws lower only in the liquid imidcloprid tretment compred with the control (P. ) (Fig. ), with no other signiþcnt pirwise comprisons (liquid imidcloprid versus liquid spinosd nd grnulr spinosd were P. nd P., respectively; liquid spinosd versus grnulr spinosd nd control were P.97 nd P.86, respectively; nd grnulr spinosd versus control ws P.67). Similr to nt density ptterns, melyug density ws lower only in the liquid imidcloprid tretment compred with the control (P. ) (Fig. ), with no other differences etween other pirwise comprisons (liquid imidcloprid versus liquid spinosd nd grnulr spinosd were P.8 nd P., respectively; liquid spinosd versus grnulr spinosd nd control ws P.9 nd P.8; nd grnulr spinosd versus control ws P.98). In contrst, fruit dmge rtings were lower in ll it tretments thn in control, nd fruit dmge ws lso lower in the grnulr spinosd thn other it tretments (Fig. C). Experiment : Imidcloprid in Lrge Plots. nt density ws lower in the imidcloprid it tretment thn in the control (F.9; df,,; P.; Fig. 6). There ws no tretment effect on melyug densities (F.7; df,, ; P.78); however, fruit dmge ws lower in the it thn control tretment (.6, P.) (Fig. 6).
June 8 DNE ET L.: RGENTINE NT CONTROL IN VINEYRDS 7 Sugr wter removed (g / dy) Melyugs / vine / min count Fruit dmge y ctegory (%) 8 6 imidcloprid () spinosd () Grnulr spinosd () imidcloprid spinosd Grnulr spinosd Mr pr My Jun Jul ug Sept Oct Nov imidcloprid () spinosd () Grnulr spinosd () Mr pr My Jun Jul ug Sept Oct Nov C Dmge rtings Fig.. nt density (), melyug density (), nd fruit dmge (C) in Snt Mri ppelltion Gewürztrminer vineyrd, infested with oscure melyug, from experiment compring liquid formultions of imidcloprid nd spinosd, grnulr formultion of spinosd, nd n untreted control. rrow indictes when its were Þrst deployed. For nt nd melyug densities, the generl liner model output is provided in ppendix, nd pirwise comprisons re provided in the text. Fruit dmge rtings differed mong tretments ( 7.8, df 9, P.); pirwise comprisons (df,.) re s follows: liquid imidcloprid versus liquid spinosd, grnulr spinosd, nd control:.6, P.; 7., P.;.87, P., respectively; liquid spinosd versus grnulr spinosd nd control: 7., P.6 nd.79, P.7, respectively; nd grnulr spinosd versus control:.6, P.. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte significnt differences etween tretments. Sugr wter removed (g / dy) Melyugs / vine / min count Fruit dmge y ctegory (%) 6 6 8 6 imidcloprid () spinosd () Grnulr spinosd () imidcloprid spinosd Grnulr spinosd Mr pr My Jun Jul ug Sept Oct Nov imidcloprid () spinosd () Grnulr spinosd () Mr pr My Jun Jul ug Sept Oct Nov c C Dmge rtings Fig.. nt density (), melyug density (), nd fruit dmge (C) in Snt Mri ppelltion Chrdonny vineyrd, infested with oscure melyug, from experiment compring liquid formultions of imidcloprid nd spinosd, grnulr formultion of spinosd, nd n untreted control. rrow indictes when its were Þrst deployed. For nt nd melyug densities, the generl liner model output is provided in ppendix, nd pirwise comprisons re provided in the text. Fruit dmge rtings differed mong tretments (., df 9, P.); pirwise comprisons (df,.) re s follows: liquid imidcloprid versus liquid spinosd, grnulr spinosd, nd control: 66, P.87; 7., P.9;., P., respectively; liquid spinosd versus grnulr spinosd nd control: 8.6, P. nd.9, P.8, respectively; nd grnulr spinosd versus control:., P.. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments. Experiment : Thimethoxm nd Sticky rriers. nt density ws lower in thimethoxm it thn control tretment (F 6.7; df, 8, 8; P.) (Fig. 7); no nts were oserved on the exclusion vines. Melyug density ws lower in the it thn control tretment (F.7; df, 8, 8; P.) (Fig. 7). Melyug density using the destructive smpling method could not e conducted on the exclusion vines; posthrvest smple of melyugs showed low melyug densities on ll tretments (. melyugs per vine), resulting in no tretment effect (F.8; df, 9; P.6). However, fruit
76 JOURNL OF ECONOMIC ENTOMOLOGY Vol., no. Sugr it removed (g / dy) Fruit dmge y ctegory (%) 9 8 7 6 8 6 it () Jul ug Sept Oct it dmge ws lower in the it nd exclusion tretments thn the control (Fig. 7C). Discussion Experiments reported herein compred the efþccy of insecticide mterils tht re likely to e registered for use in vineyrds nd tht were deployed using potentil commercil methodologies. Three mesures of tretment performnce were tken: nt density s mesured y feeding ctivity, melyug or scle density s mesured y timed visul counts, nd fruit dmge s mesured y infesttion rtes t hrvest time. Tle summrizes tretment effects. Mesurements of nt density nd fruit dmge showed the gretest response to tretments, in prt ecuse more of these smples could e collected over wider re of ech plot, therey reducing the impct of the clumped melyug distriution (Geiger nd Dne ). nt density nd fruit dmge were lower in tretments with liquid it, compred with the control in nd of trils, respectively (Tle ). Melyug nd scle densities were less responsive to nt it tretments, with lower hemiptern pest densities in only seven of liquid it trils. There ws no Dmge rtings Fig. 6. Melyug density () nd fruit dmge () in tretments from experiment in Edn Vlley, Snt Mri, nd Snt Ynez ppelltion vineyrds compring liquid it contining.% imidcloprid (technicl grde) to n untreted control. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments. Sugr wter removed (g / dy) Melyugs / vine / min count Fruit dmge y ctegory (%) it () 8 6 8 6 it Exclusion C Dmge rtings tretment effect on nt or melyug densities or fruit dmge when grnulr protein it ws tested, s hs een shown in other studies (Silvermn nd Roulston, Rust et l., ut see Krushelnycky nd Reimer 998). options for rgentine nts in griculturl systems re limited y the low numer of registered insecticides nd lck of iologicl control gents. This is the Þrst reported successful use of liquid its in vineyrds using commercilly vile deployment methodologies. Experimentl its contining Þpronil or thimethoxm provided rgentine nt control in citrus orchrds (Klotz et l. ) nd vineyrds (Dne et l. 6), wheres studies with oric cid it () Fig. 7. nt density (), melyug density (), nd fruit dmge (C) in Crneros vineyrd, infested with grpe melyug, in tretments compring liquid it contining.% thimethoxm (technicl grde), n untreted control, nd vines with sticky rrier to fully exclude nts. Fruit dmge differed mong tretments (.9, df 6, P.); pirwise comprisons (df,.) re s follows: follows: control versus it:.86, P.; control versus exclusion:.76, P.; it versus exclusion:., P.6. Different letters in prentheses (insect densities) or ove ech r (fruit dmge) indicte signiþcnt differences etween tretments.
June 8 DNE ET L.: RGENTINE NT CONTROL IN VINEYRDS 77 Tle. Summry of nt it tretment effects in the four experiments; tretments were significntly lower (L), higher (H) or not different ( ) from the control Tril Tretment Site Pest nt density Pest density Fruit dmge Exp. ImidclopridÐliquid Np EFLS Ñ Ñ Ñ Edn Vlley OM L L L oric cidðliquid Np EFLS L Ñ L Edn Vlley OM L L L ThimethoxmÐliquid Np EFLS L Ñ L Edn Vlley OM L L L Exp. ImidclopridÐliquid Sonom GM L L L Snt Mri-G OM L Ñ L Snt Mri-C OM L L L SpinosdÐliquid Sonom GM L L Ñ Snt Mri-G OM L Ñ Ñ Snt Mri-C OM Ñ Ñ L SpinosdÐgrnulr Sonom GM Ñ Ñ Ñ Snt Mri-G OM Ñ Ñ Ñ Snt Mri-C OM Ñ Ñ Ñ Exp. ImidclopridÐliquid Centrl Cost OM L Ñ L Exp. ImidclopridÐliquid Crneros GM L L L Tnglefoot exclusion Crneros GM L Ñ L Np Vlley Chrdonny (Np); Edn Vlley Chrdonny (Edn Vlley); Sonom Vlley Pinot Noir (Sonom); Snt Mri Gewürztrminer (Snt Mri-G); Snt Mri Chrdonny (Snt Mri-C); Centrl Cost (Snt Ynez Chrdonny, Snt Mri Gewürztrminer nd Chrdonny, nd Edn Vlley Chrdonny); nd Crneros (Crneros Pinot Noir. Hemiptern pests re Europen fruit lecnium scle (EFLS), oscure melyug (OM), nd grpe melyug (GM). its hve een limited to orgnic citrus grooves (Greenerg et l. 6). Results indicte tht ny of the tested mterils (oric cid, imidcloprid, thimethoxm, or spinosd) cn suppress rgentine nts when properly delivered in liquid sucrose it. Of the mterils tested, imidcloprid, spinosd, nd oric cid my e redily registered for use in griculturl systems. Imidcloprid is lredy registered for use s oth folir nd systemic formultions for melyug nd lefhopper (ut not nt) in vineyrds, nd it is one of the more commonly used insecticides in griculturl systems. Spinosd my e of prticulr interest to some growers ecuse it is n orgniclly registered chemicl tht is leled for use on grpes (pplied s folir) nd mny other crops. oron (s the fertilizer oric cid or orte) is common mendment in vineyrds. Previous studies hve shown complete nt exclusion using either insecticides or sticky rriers (e.g., González-Hernández et l. 999) or experimentl liquid it deployment (Dne et l. 6) cn result in reduction of hemiptern pests. This is the Þrst report of liquid it, pplied using commercil methodologies, lowering oth rgentine nt densities nd the ssocited hemiptern pest crop dmge ( of trils). It is noteworthy tht seson-long pest densities were lowered in only hlf of the liquid-it trils (seven of ), providing dditionl informtion for development of commercil progrm. First, the hemiptern pests in the study hd reltively long genertionl times with only one to two (Europen fruit lecnium scle nd grpe melyug) or three to four (oscure melyug) nnul genertions. This provided little time for chnges in nt densities to effect chnges in hemiptern pest densities. Second, their reduction fter tending nts re removed is typiclly ssocited with higher densities or effectiveness of nturl enemies (Dne et l. 7). t ech site, the levels of nturl enemies present will vry thus ffecting the time needed to impct pest densities. Third, nt exclusion using liquid its ws not complete, immedite, or seson-long, (nt reduction ws typiclly gretest in June, July nd ugust). However, we provide evidence tht complete, seson-long nt exclusion my not e needed to suppress hemiptern pest densities (Fig. 7). Development of vile commercil progrm is lso ided y informtion grnered in those liquid it trils where there ws no effect on nt densities. For exmple, we found tht when the polyurethne it dispensers were exposed to sunlight there could e photo-degrdtion of the imidcloprid in solution in only few hours, which my hve contriuted to the ineffectiveness of liquid it in one tril (Fig. ). In contrst, there ws reduction in seson-long nt densities in other imidcloprid tretments conducted in the Centrl Cost region (Figs. nd 6), nd we suspect the lower summer tempertures, more foggy dys, nd denser vine cnopy etter protected the it dispensers from sunlight nd reduced the photo-degrdtion of the insecticide. In the experiments, in which imidcloprid produced more consistent effects, the it dispensers were protected from sunlight with Styrofom continers, which oth shielded the solution from light nd moderted the temperture of the it solution, minimizing evportion nd decresing the frequency t which the its need reþlling. concurrent reserch study showed signiþcnt negtive correltion etween the density of rgentine nts nd it sttions deployed (Nelson nd Dne 7). This is nother concern for the commerciliztion of liquid its in perennil crop systems: how mny sttions should e deployed per h? The lrgeplot experiment, conducted in Þve seprte vineyrds, ws designed to test liquid its dispersed over lrger
78 JOURNL OF ECONOMIC ENTOMOLOGY Vol., no. re nd using fewer it sttions per h. lthough there ws reduction in nt ctivity (Fig. 6), there ws no effect on melyug density. Importntly, there ws considerle fruit dmge, with % lost crop (Fig. 6). lthough fruit dmge in the liquid it tretment ws sttisticlly lower thn in the control, this level of crop loss would e uncceptle for most vineyrd mngers. s mentioned, hemiptern pest densities my not quickly respond to chnges in nt densities. In this experiment, potentil ßw in the experimentl design ws tht it dispensers were deployed reltively lte in the seson (8 MyÐ July). lthough liquid its seemed to hve their gretest impct on the summer nt densities, the deployment ws possily too lte for effective pest suppression. rood production for rgentine nts reches sesonl high in Mrch (Mrkin 97), with most of this rood directed towrd queen development. Similrly, immture melyugs for the second genertion of oth grpe melyug (Geiger nd Dne ) nd oscure melyug (Dne et l. 7) hve een produced y this time, nd they cn infest fruit clusters s erly s July, therey providing little time for reduction in nt densities to result in reduced melyug densities or dmge. rgentine nts hve ecome key pest in mny griculturl systems. Vineyrd mngers currently hve few options other thn rrier sprys for their control. The work reported herein summrizes severl lrge Þeld experiments, deploying, monitoring tues to mesure nt ctivity nd rting,6 fruit clusters for pest dmge. In ggregte, results showed tht smll mounts of insecticide delivered in liquid, sucrose its cn suppress rgentine nts in vineyrds, which seems to lso reduce ssocited hemiptern pests nd their dmge to the crop. When properly delivered, ll insecticide mterils tested were effective. Wht remins needed for commerciliztion is informtion on it sttion deployment rte nd sesonl periods of deployment, nd inexpensive it sttions nd itðinsecticide formultions. cknowledgments We thnk Luke Powell, Clr Funk, Sen Pelhm, Mi Orsini, Eline Shplnd, Ssh Mortezei, Kevin Fingermn, Derek Fehrer for Þeld nd lortory work; Cmri (Kevin Sge), Domine Chndon (Ktey Tylor), PciÞc Vineyrd (Erin mrl nd George Donti), Sski Vineyrd (Jnet Sski), Sutter Home (Todd erg), White Hills (Dve Winemn), nd Wolff Vineyrds (Jen-Pierre Wolff) vineyrds for use of Þelds nd help with mngement of these Þeld sites; nd the mericn Vineyrd Foundtion, Viticulture Consortium, the Cliforni Competitive Grnts Progrm for Enology nd Viticulture, nd the Centrl Cost Vineyrd Tem for funding. References Cited ker, T. C., S. E. Vn Vorhiskey, nd L. K. Gston. 98. it preference tests for the rgentine nt (Hymenopter: Formicide). J. Econ. Entomol. 78: 8Ð88. lchly, J. S., nd. T. Forschler. 996. Suppression of lteseson rgentine nt (Hymenopter: Formicide) Þeld popultions using perimeter tretment with continerized its. J. Econ. Entomol. 89: 97Ð. uckley, R., nd P. Gulln. 99. More ggressive nt species (Hymenopter: Formicide) provide etter protection for soft scles nd melyugs (Homopter: Coccide, Pseudococcide). iotropic : 8Ð86. Chen, J.S.C., nd P. Noncs.. Nestmte recognition nd intrspeciþc ggression sed on environmentl cues in rgentine nts (Hymenopter: Formicide). nn. Entomol. Soc. m. 9: Ð7. Cost, H. S., L. Greenerg, J. Klotz, nd M. K. Rust.. Monitoring the effects of grnulr insecticides for rgentine nt control in nursery settings. J. gric. Urn Entomol. 8: Ð. Dne, K. M., K. R. Sime,. N. Hogg, M. L. Cooper, M. L. inchi, M. K. Rust, nd J. H. Klotz. 6. Effects of liquid insecticide its on rgentine nts in CliforniÕs costl vineyrds. Crop Prot. : 9Ð6. Dne, K. M., K. R. Sime, J. Fllon, nd M. L. Cooper. 7. Ecologicl impcts of rgentine nts on popultions of melyugs nd their nturl enemies. Ecol. Entomol. : 8Ð96. Geiger, C.., nd K. M. Dne.. Sesonl movement nd smpling of the grpe melyug, Pseudococcus mritimus (Ehrhorn) (Homopter: Pseudococcide) in Sn Joquin Vlley vineyrds. J. Econ. Entomol. 9: 9Ð. Golino, D.., S. Sim, R. Gill, nd. Rowhni. 999. Four species of Cliforni melyugs cn trnsmit lefroll disese. m. J. Enol. Viticul. : 67Ð68. González-Hernández, H., M. W. Johnson, nd N. J. Reimer. 999. Impct of Pheidole megcephl (F.) (Hymenopter: Formicide) on the iologicl control of Dysmicoccus revipes (Cockerell) (Homopter: Pseudococcide). iol. : Ð. Greenerg, L., J. H. Klotz, nd M. K. Rust. 6. orte its for control of rgentine nt, Linepithem humile in orgnic citrus (Hymenopter: Formicide). Fl. Entomol. 89: 69Ð7. Holwy, D.., L. Lch,. V. Surez, N. D. Tsutsui, nd T. J. Cse.. Cuses nd consequences of nt invsions. nnu. Rev. Ecol. Syst. : 8Ð. Klotz, J. H., M. K. Rust, H. S. Cost, D.. Reierson, nd K. Kido.. Strtegies for controlling rgentine nts (Hymenopter: Formicide) with sprys nd its. J. gric. Urn Entomol. 9: 8Ð9. Klotz, J. H., M. K. Rust, D. Gonzlez, L. Greenerg, H. Cost, P. Phillips, C. Gispert, D.. Reierson, nd K. Kido.. Directed sprys nd liquid its to mnge nts in vineyrds nd citrus groves. J. gric. Urn Entomol. : Ð. Knight, R. L., nd M. K. Rust. 99. Repellency nd efþccy of insecticides ginst forging workers in lortory colonies of rgentine nts (Hymenopter: Formicide). J. Econ. Entomol. 8: Ð8. Knight, R. L., nd M. K. Rust. 99. EfÞccy of formulted it for control of rgentine nt (Hymenopter: Formicide). J. Econ. Entomol. 9: 6Ð8. Krushelnycky, P. D., nd N. J. Reimer. 998. EfÞccy of Mxforce it for control of the rgentine nt (Hymenopter: Formicide) in Hlekl Ntionl Prk, Mui, Hwii. Environ. Entomol. 7: 7Ð8. Mrkin, G. P. 97. The sesonl life cycle of the rgentine nt, Iridomyrmex humilis (Hymenopter: Formicide), in southern Cliforni. nn. Entomol. Soc. m. 6: 8Ð.
June 8 DNE ET L.: RGENTINE NT CONTROL IN VINEYRDS 79 Mrkin, G. P. 97. Forging ehvior of the rgentine nt in Cliforni citrus grove. J. Econ. Entomol. 6: 7Ð7. Nelson, E. H., nd K. M. Dne. 7. Improving liquid it progrms for rgentine nt control: it sttion density. Environ. Entomol. 6: 7Ð8. Rust, M. K.. Insecticides nd their use in urn structurl pest control, pp. Ð. In R. Krieger [ed.], Hndook of pesticide toxicology. cdemic, Sn Diego, C. Rust, M. K., nd R. L. Knight. 99. ling rgentine nts in urn situtions, pp. 66Ð67. In R. K. Vn der Meer, K. Jffe, nd. Cedeno [eds.], pplied myrmecology: world perspective. Westview, oulder, CO. Rust, M. K., K. Hgsm, nd D.. Reierson. 996. rrier sprys to control rgentine nts (Hymenopter: Formicide). J. Econ. Entomol. 89: Ð7. Rust, M. K., D.. Reierson, nd J. H. Klotz.. Delyed toxicity s criticl fctor in the efþccy of queous its for controlling rgentine nts. J. Econ. Entomol. 97: 7Ð. Snders, N. J., K. E. rton, nd D. M. Gordon.. Longterm dynmics of the distriution of the rgentine nt, Linepithem humile, nd ntive nt tx in northern Cliforni. Oecologi (erl.) 7: Ð. Silvermn, J., nd T. H. Roulston.. cceptnce nd intke of gel nd liquid sucrose compositions y the rgentine nt (Hymenopter: Formicide). J. Econ. Entomol. 9: Ð. Surez,. V., J. Q. Richmond, nd T. J. Cse.. Prey selection in horned lizrds following invsion of rgentine nt in southern Cliforni. Ecol. ppl. : 7Ð7. Systt Softwre, Inc. 7. SYSTT version.. Systt Softwre, Inc., Point Richmond, C. Tniguchi, G., T. Thompson, nd. Sipes.. of the ig-heded nt, Pheidole megcephl (Hymenopter: Formicide) in pinepple cultivtion using mdro in it sttions. Socioiology : Ð7. Tollerup, K. E., M. K. Rust, K. W. Dorschner, P.. Phillips, nd J. H. Klotz.. Low-toxicity its control nts in citrus orchrds nd grpe vineyrds. Clif. gric. 8: Ð 7. Tsutsui, N.D.., V. Surez, nd R. K. Groserg.. Genetic diversity, symmetricl ggression, nd recognition in widespred invsive species. Proc. Ntl. cd. Sci. U.S.. : 78Ð8. Veg, S. J., nd M. K. Rust.. rgentine nt: signiþcnt invsive species in griculturl, urn nd nturl environments. Socioiology 7: Ð. Received ugust 7; ccepted Jnury 8. ppendix. Reltionship of tretments of different nt it ctive ingredients (.% oric cid,.% imidcloprid,.% thimethoxm, nd n untreted control) nd smple dte on the seson long nt nd melyug or scle densities Smple Comprison Np Vlley, Edn Vlley, F-rtio df P vlue F-rtio df P vlue nt density Tretment 7.9... Smple dte. 6..77. Tretment dte.8 78... Melyug or scle density Tretment.9. 8.9. Smple dte.98 6..6. Tretment dte.76 8.988.99 9.6 See Figs. nd for presenttion of dt from the Np Vlley nd Edn Vlley vineyrds, respectively. The Np Vlley vineyrd ws infested with Europen fruit lecnium scle, nd the Edn Vlley vineyrd ws infested with oscure melyug. ppendix. Reltionship of tretments of different commercil nt its (.% spinosd [liquid nd grnulr],.% imidcloprid, nd n untreted control) nd smple dte on the seson long nt nd melyug densities Smple Comprison Sonom Vlley, Snt Mri (Gewürztrminer), Snt Mri (Chrdonny), F-rtio df P vlue F-rtio df P vlue F-rtio df P vlue nt density Tretment.9....666.6 Smple dte. 8. 6. 6.. 7. Tretment dte 6.66..6 8..8.697 Melyug density Tretment 8.69. 7.9..6. Smple dte.9 6. 9. 6..7 6. Tretment dte.9 8.6.6 8..69 8.87 See Figs.,, nd for presenttion of dt from the Sonom Vlley Pinot Noir, Snt Mri Gewürztrminer, nd Snt Mri Chrdonny trils, respectively. The Sonom vineyrd ws infested with grpe melyug, nd the Snt Mri vineyrds were infested with oscure melyug.