Improved quality of fungicide deposition and coverage of potato leaves using flat fan air-injector nozzle IDK

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1 COBISS Code 1.01 DOI: /v Agrovoc descriptors: solnum tuerosum, pottoes, root vegetles, spryers, nozzles, ppliction methods, chemicl control, control methods, fungicides, plnt protection, disese control, equipment, plnt protection equipment, equipment, equipment prts Agris ctegory code: h20, n20 Improved qulity of fungicide deposition nd coverge of potto leves using flt fn ir-injector nozzle Filip VUČAJNK 1, Rjko BERNIK 2 Received Jnury 16, 2012; ccepted Ferury 20, Delo je prispelo 16. jnurj 2012, sprejeto 20. ferurj ABSACT The im of our experiment ws to improve fungicide spry deposition nd coverge of potto leves y using ir-injector nozzle types. We used two stndrd nozzle types - flt fn nozzle nd hollow cone nozzle, s well s couple of ir-injector nozzle types - n ir-injector compct nozzle nd symmetric doule flt fn ir-injector nozzle (with 30 forwrd nd 30 ckwrd spry jet ngle). Wter-sensitive pper ws plced on the upper, middle nd lower prt of the plnt in order to determine the qulity of fungicide deposition nd the ility of droplets to penetrte lower prts of the plnt. When using the ir-injector compct nozzle, potto leves were covered well t ll three levels of the plnt. The use of the ove-mentioned nozzle resulted in the lowest reduction in coverge vlue nd droplet impression re from the top towrds the lowest prt of the plnt. Furthermore, the nozzle creted lrge enough droplets with sufficient mss nd speed to penetrte the dense cnopy ll the wy to the lowest prt of the plnt. When using the symmetric doule flt fn ir-injector nozzle, the ngle of oth spry jets ws excessively wide in order for the droplets to rech the lower prt of the plnt despite very lrge droplet impression re. The use of oth stndrd nozzle types resulted in poor spry mixture coverge of the middle nd lower prt of the plnt. This predominntly occurred due to insufficient droplet size nd the susequent lck of kinetic energy. Results show tht the use of newer ir-injector compct nozzle improves the deposition nd coverge of potto leves with spry mixture. Key words: deposition, coverge, nozzles, potto, fungicide IZVLEČEK IZBOLJŠANJE DEPOZICIJE IN POKRITOI LIOV KROMPIRJA S ŠKROPILNO BROZGO PRI UPORABI INJEKTORSKE ŠPRANJAE ŠOBE Nmen poskus je il izoljšnje nnos in pokritosti listov krompirj s škropilno rozgo pri upori novejših izved injektorskih šo. Uporili smo dve stndrdni izvedi šo, šprnjsto šoo in vrtinčno šoo ter dve injektorski izvedi šo, šoo in šoo z dvojnim simetričnim curkom (škropilni curek pod kotom 30 o nprej in 30 o nzj). N zgornji, srednji in spodnji del rstline smo nmestili n vodo očutljive lističe, d i pri uporljenih šoh ugotovili kkovost fungicidneg nnos in sposonost prodirnj kpljic v spodnje dele rstlin. Ugotovili smo, d je il njoljš pokritost listov krompirj n vseh etžh pri upori injektorske šoe. Pri tej šoi je ilo njmnjše zmnjšnje odstotk pokritosti in površine odtis posmezne kpljice od vrh proti spodnjemu delu rstline. T šo tvori dovolj velike kpljice, ki imjo veliko hitrost in zdostno mso, d lhko prodrejo skozi gost listni sestoj do spodnjeg del rstline. Pri injektorski šoi z dvojnim simetričnim curkom je il kot oeh škropilnih curkov prevelik, d i kpljice zdele spodnji del rstline, klju temu d je il površin odtis posmezne kpljice zelo velik. Pri oeh stndrdnih izvedh šo je il presl pokritost s škropilno rozgo v srednjem in spodnjem delu rstline predvsem zrdi premjhnih kpljic in posledično premjhne kinetične energije. Rezultti kžejo izoljšnje depozicije in pokritosti listov krompirj s škropilno rozgo pri upori novejše injektorske šoe. Ključne esede: nnos, pokritost, šoe, krompir, fungicid 1 2 Ph.D., University of Ljuljn, Biotechnicl Fculty, Deprtment of Agronomy, Jmnikrjev 101, SI-1111 Ljuljn, e-mil: filip.vucjnk@f.uni-lj.si Prof., Ph.D., Biotechnicl Fculty, Deprtment of Agronomy, Jmnikrjev 101, SI-1111 Ljuljn Act griculture Slovenic, 99-2, septemer 2012 str

2 Filip VUČAJNK, Rjko BERNIK 1 INODUCTION Spry deposition on the trget surfce proved to e the decisive fctor in sprying with plnt protection products (PPP). It is possile to ffect the qulity of spry deposition on the trget surfce y chnging droplet size, volume ppliction rte, pressure nd driving speed. Fine droplets cn provide etter fungicide coverge, however, with lesseffective droplet penetrtion through the cnopy (Stngl, 2009). Required volume ppliction rte nd dequte fungicide deposition rte result in good spry coting on the trget surfce nd represent the sic requirement for n effective disese control. Lower volume ppliction rte results in smller numer of droplets nd smller spry coting on the trget surfce (Brune, 2011). Potto hs different morphology thn other cultivted plnts. Its lef-re index (LAI) is 4 nd it hs complex system of intertwined stems nd leves t different levels which proves to e prolemtic for the penetrtion of fungicides through the cnopy. Spry deposit should eqully cover ll prts of the plnt in the highest possile degree. Potto hs villous leves nd stems with cuticles enling qulity fungicide deposition. Potto epidermis, on the other hnd, does not hve n extr epicuticulr wx lyer, chrcteristic of some other plnts, such s oilseed rpe, cge etc. (Strsurger, 1991). When spry droplets touch the lef surfce, they stick to it nd finlly rerrnge throughout the surfce. There is no risk of droplets ouncing off the leves or trickling wy (Luckhrd nd Brune, 2011). In the potto lte light control, timely sprying nd high-qulity fungicide deposition re of extreme importnce. The chemicl control should involve nozzles with medium droplet size (VMD µm). Nozzles with spry jet t certin ngle from the verticl llow etter lef coverge, prticulrly during the min stem elongtion nd ll the wy to the point where plnts meet etween the rows (BBCH ) (Spry Appliction Technique, 2003). Nowdys, new sprying techniques re eing introduced nd tested in the potto lte light control. These involve reduced volume ppliction rte (less thn 50 l/h) in Dnfoil spryers, use of stndrd nozzles on irssisted spryers, under lef fungicide deposition nd use of nozzles with different spry jets on clssic spryers (Kryger Jensen, 2007). Severl uthors determined the effect of vrious nozzle types on the coverge of potto leves with fungicides. According to Kierzek nd Wchowik (2009), the est coverge of potto leves cn e chieved y using driftreducing nozzles nd doule flt fn nozzles. On the lower prt of the plnt, coverge of the upper prt of the leves ws 3 to 5 times etter thn on the lower prt of the leves. Furthermore, Kierzek nd Wchowik (2007) determined the highest spry deposit nd the est coverge of potto plnt with the use of specil flt fn nozzle with spry jet revolved ckwrds t 30 ngle from the verticl. An ir-ssisted spryer ws used in the tril. Airinjector flt fn nozzle with single spry jet nd stndrd flt fn nozzle were oth less effective in the coverge of potto leves. Kryger Jensen (2007) stted similr iologicl efficcy of ir-injector nozzles in comprison with stndrd nd drift-reducing nozzles. Bckwrd ngled nozzles proved to rech etter coverge of potto leves thn nozzles with verticl spry jet. At times, irssisted spryers prove to e more iologiclly effective. With Dnfoil spryers, smller volume ppliction nd fungicide deposition rtes my e used. This could, however, result in reduced iologicl efficcy. Under-lef deposition of spry mixture my improve the efficcy ut it would simultneously reduce 152 Act griculture Slovenic, 99-2, septemer 2012

3 Improved qulity of fungicide nozzle the re efficiency nd rise the expenses (Kryger Jensen, 2007). According to Klusen (2007), ir-injector nozzles proved to e more effective in the coverge of potto leves in comprison with stndrd nozzles. The coverge on the upper prt of the plnt ws etter when ir-ssisted spryers nd Dnfoil spryers hd een used. The use of Dnfoil spryers resulted in the est coverge of the middle prt of the plnt. With reduced volume ppliction rte (120 l/h), the lrgest coverge ws reched y irssisted spryers nd Dnfoil spryers. Kierzek (2007) compred the fungicide deposition qulity on potto plnts etween stndrd nozzle with verticl spry jet nd nozzle with 45 spry jet. In comprison with the stndrd nozzle, the ltter reched n pproximtely 50% etter coverge of the upper prt of the leves. Coverge of the lower prt of the leves with the nozzle hving 45 spry jet ws 3-5 times etter. Gjtkowski et l. (2005) determined tht, in comprison with ir-injector nozzles, the use of stndrd nozzles results in etter coverge of potto leves. With the pressure rised from 2 to 4 rs, the numer of droplets per cm 2 when ir-injector nozzles hd een used ws reduced under the llowed limit (20 droplet impressions per cm 2 ). Stlling et l. (2010) wnted to determine the effect of driving speed nd vrious nozzle types on spry deposition qulity nd iologicl efficcy of Shirln fungicide (AI fluzinm) in potto lte light control. At the referentil 100% ppliction rte, there were no sttisticlly significnt differences. They did, however, occur with smller fungicide nd volume ppliction rtes (65 nd 135 l/h respectively). Stndrd nozzles reched etter results thn ir-injector nozzles. An increse of the driving speed from 2 to 4 m/s reduced iologicl efficcy of the fungicide used t the referentil 100% ppliction rte. Furthermore, droplet impression numer per cm 2 dropped y 40-75%. Authors discovered tht the droplet impression numer per cm 2 lower thn 120 reduces iologicl efficcy. Coverge vlue nd droplet impression numer per cm 2 were reduced, from the top towrds the lower prt of the plnt. Knewitz nd Koch (2010) estlished tht, in comprison with single spry jet ir-injector nozzles, the use of symmetric doule flt fn ir-injector nozzles resulted in etter coverge of potto plnt. The coverge reched y using the symmetric doule flt fn ir-injector nozzle ws, however, slightly smller thn with other ir-injector nozzle types. Luckhrd nd Brune (2011) confirmed much etter spry deposition on the upper two thirds of the plnt in comprison with the lower third of the plnt, regrdless of the nozzle type. In comprison with other ir-injector nozzle types, the use of symmetric doule compct ir-injector nozzles resulted in etter coverge of potto plnt. Asymmetric nd symmetric doule flt fn ir-injector nozzles reched etter coverge vlues thn single spry jet ir-injector nozzles. Due to smller numer of droplets, the coverge of potto plnt t 150 l/h volume ppliction rte ws much smller thn t 350 l/h. Due to smller numer of corse droplets, droplet impression mss on the upper third of the plnt ws reltively high, wheres the coverge vlue ws smll. Despite the extremely corse ( µm) nd corse ( µm) volume medin dimeter (VMD) of droplets formed y nozzles, spry deposition on the leves ws good due to specil lef surfce structure of potto plnt. Fungicide deposition qulity proved to e etter t 350 l/h thn t 150 l/h volume ppliction rte. The im of the tril ws to determine the spry deposition qulity on potto leves ccording to vrious nozzle types. Furthermore, we wnted to reserch the coverge of potto Act griculture Slovenic, 99-2, septemer

4 Filip VUČAJNK, Rjko BERNIK leves with spry mixture on the lower prt of the plnt nd to determine which nozzle type is the most suitle one for penetrting the thick cnopy, from the top towrds the lower prt of the plnt. Two stndrd nozzle types were used in the tril, nmely flt fn nozzle nd hollow cone nozzle. We lso included two newer nozzle types single spry jet ir-injector compct nozzle nd symmetric doule flt fn ir-injector nozzle AVI-. In Sloveni, it is customry to use stndrd nozzles. Air-injector nozzles, on the other hnd, re used less frequently. We were interested in finding out whether the new nozzle types ensure etter spry deposition on potto leves in comprison with stndrd nozzles. We put forth hypothesis tht, prticulrly in the middle nd lower prt of the plnt, the use of the two ir-injector nozzle types ensures etter spry deposition in comprison with the two stndrd nozzle types. Moreover, we presumed tht oth irinjector nozzle types re le to penetrte the cnopy etter thn the stndrd nozzle types. 2 MATERIALS AND METHODS 4 different nozzle types - 2 stndrd ones nd 2 ir-injector ones were used in the potto sprying tril (Figure 1). Among the stndrd nozzle types, there were stndrd flt fn nozzle nd stndrd hollow cone nozzle C, while ir-injector nozzle types included flt fn ir-injector nozzle C nd symmetric doule flt fn ir-injector nozzle AVI The ltter hd 30 forwrd nd 30 ckwrd spry jet in ccordnce with the sprying direction. Figure 1: Nozzles used in the tril The tril ws performed on lighter soil, in Dol pri Ljuljni, in the yer The tril ws sed on 3 rndom locks with 3 repetitions within tril units. Ech of three lock ws 12 m wide nd 5 m long. 10 m divider strips were creted mong the locks. Within ech lock, vrious nozzle types were rndomly distriuted long the spry oom. Nozzles of the sme type were plced together in groups of 4 or 5, it mens 2 to 2.5 m wide. In the tril, medium-to-lte Aldin potto cultivr ws used t 75 cm inter row width. Pottoes were plnted t distnce of 29.6 cm, creting n exct tuer density of 45,000/h. During the inflorescence emergence, when pproximtely 40% of flowers were lredy open (BBCH 604), potto ws spryed with systemic nd contct fungicide Melody Duo (AI iprovlicr nd propine) t 2.5 kg/h ppliction rte. This fungicide is used in potto lte light (Phytophthor infestns) nd 154 Act griculture Slovenic, 99-2, septemer 2012

5 Improved qulity of fungicide nozzle erly light (Alternri solni) control during the period of intensive growth. During the sprying, plnts were 70 cm high. Ech tretment involved three rndomly selected plnts in the sme row. The chosen plnts were lwys locted in the middle, on the spot corresponding to the third nozzle (out of five) of ech nozzle type. We thus mnged to void the edge effect of spry jets from the djcent nozzle types on our mesuring plce. We ttched wter-sensitive pper to the upper lef surfce in the upper (70 cm from the ground), middle (40 cm from the ground) nd lower prt (10 cm from the ground) of the plnt (Figure 2). This ws done with the id of pperclips. There ws pprox. 30 cm of verticl distnce mong vrious mesuring ppers. Mesuring ppers were 76 mm long nd 26 mm wide. Ech tretment involved 9 mesuring ppers. Due to possile effect of trctor/spryer pssge on the spry deposition on mesuring ppers, mesurements were not performed long the trmlines. Trctor mounted spryer with 600 l tnk cpcity nd 12 m wide spry oom ws used in the tril (Figure 3). Spry oom ws locted 50 cm from the trget surfce. Driving speed during the sprying ws 4.1 km/h nd working pressure mounted to 4.0 rs. There ws 400 l/h volume ppliction rte. Volume medin dimeter (VMD) of droplets for ech nozzle type is shown in Tle 1. Air temperture during the sprying ws 15 C, with 67% reltive ir humidity nd 0.8 m/s wind speed. After the sprying, mesuring ppers were collected nd nlysed. Figure 2: Wter-sensitive pper on the upper prts of plnts Act griculture Slovenic, 99-2, septemer

6 Filip VUČAJNK, Rjko BERNIK Figure 3: Sprying the field tril with trctor mounted spryer Tle 1: VMD of droplets nd droplet distriution ccording to BCPC nd ASAE for ech nozzle used in the tril, the pressure of 4.0 rs ws used in ll cses Nozzle type VMD (µm) Droplet distriution ccording to BCPC nd ASAE fine C 380 corse AVI corse C 100 very fine Droplet impressions on mesuring ppers were nlysed with Optomx Imge Anlyser. Three mesurements were performed on ech mesuring pper. In the APA 2001 V5.1 progrm, we clculted the coverge vlue nd the droplet impression numer per cm 2. Bsed on this dt, impression re of single droplet ws clculted s quotient of coverge vlue nd droplet impression numer per cm 2. In ddition, reltive reductions in coverge vlue nd impression re of single droplet, from the top towrds the lowest prt of the plnt, were nlysed. Coverge vlue nd impression re of single droplet on the upper prt of the plnt ment 100%. Sttisticl nlysis ws performed ccording to the procedure vlid for rndom locks with repetitions within the tril units (Košmelj, 2001; Hdživuković, 1991). We initilly exmined homogeneity of vrince, using Hrtley ' s test. Coverge vlue dt, reltive reduction in coverge vlue nd reltive reduction in impression re of single droplet were then trnsformed with the sin (sqrt) function. Anlysis of vrince nd Duncn s Multiple Rnge Test were performed t α = A seprte nlysis of the upper, middle nd lower prt of the plnt ws performed. It ws followed y joint nlysis of seprte prts of the plnt. This gve us more ccurte picture on the spry deposition on the trget surfce ccording to individul nozzle types. If present, sttisticlly significnt differences mong vrious tretments were mrked with different letters. All sttisticl nlyses were performed y the Sttgrph 4.0 progrm (Sttisticl Grphics Corp., Mnugistics, Inc.). 156 Act griculture Slovenic, 99-2, septemer 2012

7 Improved qulity of fungicide nozzle 3 RESULTS AND DISCUSSION In comprison with the symmetric doule flt fn ir-injector nozzle (37%), the stndrd hollow cone nozzle reched etter coverge vlue (47%) on the upper prt of the plnt (Figure 4). It is presumed tht the slightly higher coverge vlue of the stndrd hollow cone nozzle ws the result of higher droplet impression numer per cm 2 (65) when compred with oth ir-injector nozzle types, nmely nd (with 40 nd 42 droplet impressions respectively). Compred to the nozzle, the nozzle forms smller numer of droplets, which re, however, corser, cusing the lck of sttisticlly significnt differences in the coverge vlue. nozzle forms lrger numer of very fine droplets with the volume medin dimeter of 100 µm. Results of the impression re of single droplet mounting to 0.72 mm 2 prtilly prove tht fct (Figure 6). Volume medin dimeter of the symmetric doule flt fn ir-injector nozzle ws proly excessive (pprox. 410 µm), cusing the coverge vlue of this nozzle to e slightly lower. Higher pressure vlues nd slightly higher numer of droplets per cm 2 would rise the coverge vlue resulting from the use of this nozzle. According to nozzle producer Agrotop (2010), nozzles llow etter spry deposition on the verticlly positioned plnt prts in comprison with the horizontl prts, i.e. leves on the upper prt of the plnt, which might e the cuse of slightly worse coverge vlue. Gjtkowski et l. (2005) stted tht good fungicide deposition onto potto plnts should involve t lest 50 droplet impressions per cm 2 nd coverge vlue higher thn 15%. In our tril, oth ir-injector nozzle types proved to deposit less thn 50 droplets per cm 2. On the other hnd, the coverge vlue they reched lrgely exceeded the ove-mentioned 15%. Due to this fct, the qulity of spry deposition ws very high with ir-injector nozzles s well. Results of coverge vlue indicte very good qulity of fungicide deposition on the upper prt of the plnt with ll nozzle types used in the tril. This ws concluded due to the fct tht the upper prt of the plnt does not impede the droplets to rech the trget surfce. Moreover, its leves re well exposed to the spry deposition. Our results prtilly correspond to the results of Gjtkowski et l. (2005), who stted tht, in comprison with ir-injector nozzles, the use of stndrd nozzles results in etter coverge of potto leves. In our tril, this held true merely for the stndrd hollow cone nozzle in the upper prt of the plnt. In the middle prt of the plnt, the single spry jet ir-injector compct nozzle reched significntly higher coverge vlue (31%) thn stndrd nd nozzles (with 22 nd 20% respectively). (Figure 4). Due to lrger volume medin dimeter, nozzles seem to e more efficient in the penetrtion through the cnopy, wheres the droplets formed y stndrd nd nozzles re too smll nd do not hve enough speed nd kinetic energy to penetrte deeper into the lower prts of the plnt. These results prtilly correspond to Klusen's findings (2007). The ltter proved tht the use of ir-injector nozzles results in etter coverge of potto plnt in comprison with the use of stndrd nozzles. In our tril, this held true for the middle prt of the plnt, nd not the upper one. As nticipted, in the middle prt of the plnt, oth nd stndrd nozzle types proved to hve higher droplet impression numer per cm 2 thn the nd ir-injector nozzles (Figure 5). Nevertheless, the droplets formed y oth nd stndrd nozzles were much smller thn those of the nd ir-injector nozzles. This ws, furthermore, proved y the results of the impression re of single droplet. With oth nd ir-injector nozzles, the impression re of single droplet proved to e igger (0.45 nd 0.60 mm 2 respectively) thn with the nd Act griculture Slovenic, 99-2, septemer

8 Filip VUČAJNK, Rjko BERNIK stndrd nozzles (0.21 nd 0.18 mm 2 respectively) (Figure 6). When compring the two ir-injector nozzles, the single spry jet nozzle proved to rech higher droplet impression numer per cm 2 (68) thn the symmetric doule flt fn nozzle (42). It is thus possile to conclude tht oth spry jets of the nozzle hve n excessive forwrd nd ckwrd ngle which disled them from sending the droplets deeper into the cnopy. In comprison with the upper prt of the plnt, the middle prt hd lower coverge vlue regrdless of the nozzle type. This ws nticipted s leves present physicl ostcle in droplet penetrtion to the lowerlying prts of the plnt. The velocity of fine stndrd nozzle droplets is lower, cusing them to stop erlier on their wy in comprison with corser ir-injector nozzle droplets. The ltter hve igger mss, greter velocity nd, therefore, lrger kinetic energy. This is why they re le to penetrte the lower-lying prts of the plnt. The increse of the verticl distnce etween the nozzle nd the trget surfce resulted in higher droplet impression numer per cm 2. It cn e ssumed this occurred due to igger overlp of spry ptterns from the djcent nozzles nd finer droplets. In comprison with the upper nd middle prt, the lower prt of the plnt reched the lowest coverge vlue with ll nozzle types (Figure 4). In this spect, the results correspond to the Luckhrd nd Brune's results (2011). The uthors determined tht, on the upper two thirds of the plnt, the qulity of spry deposition is much higher thn on the lower third of the plnt regrdless of the nozzle type used. Similr to the middle prt of the plnt, the use of the single spry jet ir-injector compct nozzle resulted in etter coverge vlue (23%) of the lower prt of the plnt in comprison with other nozzle types (16-18%). Resons for qulity spry deposition on the lower prt of the plnt y the nozzle re identicl to those for the middle prt of the plnt. The nozzle hs single verticl spry jet of corse droplets t high velocity, which re le to penetrte ll the wy to the lowest prts of the plnt. The, nd nozzles ll reched coverge vlues which were only slightly higher thn 15%. According to Gjtkowski et l. (2005), tht is the lower limit for qulity fungicide ppliction onto potto plnts. Moreover, with the mjority of nozzle types, the droplet impression numer per cm 2 ws higher on the lower prt of the plnt thn on the middle prt of the plnt (Figure 5). As lredy mentioned, this is connected with the increse of distnce etween the trget surfce nd the nozzle which cuses n even igger overlp of spry ptterns from the djcent nozzles nd the reduction in droplet size. With ll nozzle types, impression re of single droplet ws smller on the leves of the lower prt of the plnt thn in its middle (Figure 6). However, the impression re of single droplet reched with oth nd irinjector nozzle types (0.27 nd 0.28 mm 2 respectively) ws sttisticlly higher thn with oth nd stndrd nozzles (0.16 nd 0.13 mm 2 respectively). 158 Act griculture Slovenic, 99-2, septemer 2012

9 Improved qulity of fungicide nozzle 60 Coverge vlue (%) * UP MP LP W Figure 4: Coverge vlue on the upper, middle nd lower prt of the plnt nd on the whole plnt ccording to the nozzle type; UP upper prt of the plnt; MP middle prt of the plnt; LP lower prt of the plnt; W the whole plnt; * mens, t the sme prt of the plnt, followed y different letters re significntly different (p < 0.05); rs represent stndrd errors c Droplet impression numer per cm * c c c d UP MP LP W Figure 5: Droplet impression numer on the upper, middle nd lower prt of the plnt nd on the whole plnt ccording to the nozzle type; UP upper prt of the plnt; MP middle prt of the plnt; LP lower prt of the plnt; W the whole plnt; * mens, t the sme prt of the plnt, followed y different letters re significntly different (p < 0.05); rs represent stndrd errors. Act griculture Slovenic, 99-2, septemer

10 Filip VUČAJNK, Rjko BERNIK 1,4 Impression re of single droplet (mm 2 /droplet) 1,2 1,0 0,8 0,6 0,4 0,2 0,0 * 1,08 0,87 0,68 0,72 0,60 0,45 0,21 0,27 0,28 0,30 0,18 0,16 0,13 0,50 0,56 0,27 UP MP LP W Figure 6: Impression re of single droplet on the upper, middle nd lower prt of the plnt nd on the whole plnt ccording to the nozzle type; UP upper prt of the plnt; MP middle prt of the plnt; LP lower prt of the plnt; W the whole plnt; * mens, t the sme prt of the plnt, followed y different letters re significntly different (p < 0.05); rs represent stndrd errors. 120 Reltive reduction in coverge vlue (%) * UP MP LP Figure 7: Reltive reduction in coverge vlue on the middle nd lower prt of the plnt in comprison with the upper prt of the plnt ccording to the nozzle type; UP upper prt of the plnt; MP middle prt of the plnt; LP lower prt of the plnt; W the whole plnt; * mens, t the sme prt of the plnt, followed y different letters re significntly different (p < 0.05); rs represent stndrd errors. 160 Act griculture Slovenic, 99-2, septemer 2012

11 Improved qulity of fungicide nozzle Reltive reduction in impression re of single droplet (%) * UP MP LP Figure 8: Reltive reduction in impression re of single droplet on the middle nd lower prt of the plnt in comprison with the upper prt of the plnt ccording to the nozzle type; UP upper prt of the plnt; MP middle prt of the plnt; LP lower prt of the plnt; W the whole plnt; * mens, t the sme prt of the plnt, followed y different letters re significntly different (p < 0.05); rs represent stndrd errors. In comprison with the upper prt of the plnt (100%), the use of nd ir-injector nozzle types reduced the coverge vlue on the middle prt to 72 nd 70% respectively (Figure 7). A much igger reduction occurred with the two stndrd nozzle types. The nozzle reduced the coverge vlue to 52%, while the reduction of the nozzle mounted to 42%. The reduction in coverge vlue on the lower prt of the plnt ws even more distinctive thn on the upper prt. Once gin, the use of stndrd nd nozzles resulted in higher reduction (38% of vlue in comprison with the upper prt) thn the two ir-injector nozzle types nd (with 54 nd 42% reduction in comprison with the upper prt). The ove-cited results show tht, predominntly with the ir-injector nozzle, the coverge vlue drops throughout the whole plnt height downwrds y slightly less thn 50%. Bsed on this it is possile to conclude tht, when this nozzle is used, sufficient numer of droplets penetrte ll the wy to the lower prt of the plnt in order to cover sufficiently lrge re. With other nozzle types, prticulrly the stndrd nd nozzles, the coverge vlue is reduced y slightly less thn 66%. When compring the reltive reduction in impression re of single droplet, from the upper towrds the lower prt of the plnt, the reltive reduction ws the lowest oth in the middle prt (reduced to 69% of the upper prt vlue) nd the lower prt of the plnt y the nozzle (reduced to 32% of the upper prt vlue) (Figure 8). Among other nozzle types (, nd ), reltive reduction in the impression re of single droplet on the middle nd lower prt of the plnt proved to e igger thn with the nozzle. There were, however, no sttisticlly significnt differences mong the three ove-stted nozzle types. Bsed on we concluded tht thick cnopy represents gret ostcle for the droplets on their wy downwrds. Furthermore, the impression re of single droplet on the lower prt of the plnt is reduced to 1/3 or 1/4 of the upper prt vlue. Impression re of single droplet is, moreover, dependent upon the verticl distnce etween the nozzle nd the trget re. In comprison with the upper prt, middle nd lower prts of the plnt were reched predominntly y rnge of finer droplets. It is importnt to ensure tht the difference in the size of droplets flling on the top of the plnt nd those reching its lower prt is not excessive. With oth stndrd Act griculture Slovenic, 99-2, septemer

12 Filip VUČAJNK, Rjko BERNIK nozzle types ( nd ), impression re of single droplet ws very smll lredy in the middle, ut even more in the lower prt of the plnt. These two nozzles form rnge of fine nd very fine droplets extremely sensitive to drift. Droplets re considered driftle if their volume medin dimeter (VMD) is smller thn 150 µm. According to Lešnik (2007), the nozzles which form very fine droplets (e.g. the nozzle) crete 50-60% of driftle droplets. Nozzles forming fine droplets (e.g. the nozzle) hve 20 to 50% driftle droplets. On the whole, flt fn ir-injector nozzle proved to hve the est fungicide deposition qulity on potto leves t ll the levels (upper, middle nd lower prt of the plnt). This nozzle reched the highest coverge vlue in the middle nd lower prt of the plnt. A sufficient numer of droplets mnged to penetrte the lowest prts of the plnt nd there ws less thn 50% reduction in coverge of the lower prt in comprison with the upper prt. Moreover, impression re of single droplet nd susequent droplet size were lso sufficiently lrge. This confirmed the hypothesis tht ir-injector nozzle types ensure etter spry deposition on potto plnts. These results prtilly correspond to Klusen's findings (2007) of etter spry deposition with ir-injector nozzles in comprison with stndrd nozzles. Nonetheless, our results re not directly comprle with his findings since his tril involved n ir-ssisted spryer nd Dnfoil spryer, while our own included stndrd spryer. The hypothesis ws only confirmed for the nozzle, nd not the symmetric doule flt fn ir-injector nozzle. The coverge vlue of this nozzle type ws insufficient prticulrly in the lower prt of the plnt. Despite sufficient impression re of single droplet, droplet impression numer per cm 2 proved to e too smll. It is ssumed tht spry jet ngles of the nozzle (30 forwrd ngle nd 30 ckwrd ngle) re too wide, thus reducing the possiility for the droplets to penetrte the lower prts of the plnt. Our findings re different to those of Knewitz nd Koch (2010), Kierzek nd Wchowik (2009), nd Luckhrd nd Brune (2011), ll determining tht the use of ir-symmetric doule flt fn injector nozzles results in etter coverge in comprison with the single spry jet irinjector nozzles. Stndrd nd nozzles reched worse coverge vlues of the middle nd lower prt of the plnt. Our results on this point re in ccordnce with Stngl's sttement (2009) tht nozzles with fine droplets re not le to sufficiently penetrte the thick cnopy. Both nozzle types form reltively fine droplets which do not hve sufficient velocity nd enough kinetic energy to penetrte the thick cnopy. Due to this fct, droplets re much more suject to drift. The nd nozzles er the most pronounced reduction in coverge vlue, prticulrly in the middle prt of the plnt where it dropped to 52% () nd 42% () in comprison with the upper prt vlue. Similr reduction occurred with the impression re of single droplet. On the middle prt of the plnt, the ltter decresed y 68% () nd 75% () in comprison with the upper prt vlue. Our results on this point do not correspond to the results of Gjtkowski et l. (2005), nd Stlling et l. (2010) who determined tht, in comprison with irinjector nozzles, the use of stndrd nozzles results in etter spry deposition on potto plnts. As nticipted, coverge vlue decresed, from the top towrds the lower prt of the plnt, regrdless of the nozzle type. This corresponds to the findings of Stlling et l. (2010). Contrry to their sttements, however, the droplet impression numer per cm 2 incresed. It is ssumed tht this ws cused due to lrger overlp of spry ptterns from the djcent nozzles nd finer droplets t 162 Act griculture Slovenic, 99-2, septemer 2012

13 Improved qulity of fungicide nozzle lrger verticl distnce etween the nozzle nd the middle/lower prt of the plnt. Our findings re limited to the fungicide deposition, excluding the reserch on the iologicl efficcy of the fungicide in potto lte light (Phytophthor infestns L.) nd erly light (Alternri solni L.) control. Nonetheless, potto lte light nd erly light infections did not occur in our tril. 4 CONCLUSION Results of the tril show the flt fn irinjector nozzle chieved the est fungicide coverge of potto leves in the upper, middle nd lower prt of the plnt. This nozzle reched the highest spry mixture coverge vlue while retining sufficient impression re of single droplet in the middle nd lower prt of the plnt. Furthermore, the coverge with spry mixture pplied y the nozzle dropped y 28% in the middle prt of the plnt nd y 46% in the lower prt, which is less thn with other nozzle types. The nozzle forms single verticl spry jet of corse droplets with enough velocity nd kinetic energy for the droplets to penetrte the thick cnopy. Results show tht the ngles of oth spry jets of symmetric doule flt fn ir-injector nozzle (the 30 forwrd nd the 30 ckwrd ngle) re excessively wide in order for the droplets to penetrte ll the wy to the lower prts of the plnt. This nozzle did thus not confirm the proposed hypothesis. The use of oth stndrd nozzle types resulted in worse coverge nd impression re of single droplet despite them hving the lrgest droplet impression numer per cm 2. The two stndrd nozzles form lrger numer of fine nd very fine droplets which re excessively light nd do not hve enough speed to penetrte ll the wy to the lower prts of the plnt. Among these droplets, there is lrge percentge of driftle droplets (< 150 µm) which re extremely sensitive to drift. Our conclusions refer to nnul results. In order to confirm results s whole, dditionl field trils should e performed in the yers to come. Further reserch should involve iologicl efficcy of fungicides ccording to vrious nozzle types. This would give us n even clerer picture on the effect of vrious nozzle types nd susequent spry deposition qulity on the efficcy of potto lte light (Phytophthor infestns) nd erly light (Alternri solni) control. 5 REFERENCES Agrotop, Aluz AVI-. [online] URL: 7.pdf Brune, R.A Wsermenge perfekt stimmen. DLZ Agrrmgzin 4: Gjtkowski, A., Bzdeg, W., Migdlsk, P Spry coverge in pottoes with low drift nd irinduction nozzles. Journl of Plnt Protection Reserch, 45, 1: Hdživuković, S Sttistički metodi. Novi Sd, Inštitut z ekonomiko poljoprivrede i sociologiju sel: 585 p. Kierzek, R New solutions in the technology of protecting pottoes from diseses. Ochron Roślin, 52, 12: Kierzek, R., Wchowik, M Effect of new spry equipments on the lef coverge of potto. Progress in Plnt Protection, 47, 1: Kierzek, R., Wchowik, M Effect of new spry nozzles on potto lef coverge with working liquid. Progress in Plnt Protection, 49, 3: Klusen, N.E Sprying technique in potto. [online] URL: Act griculture Slovenic, 99-2, septemer

14 Filip VUČAJNK, Rjko BERNIK df Košmelj, K Sttistične metode. Delovno grdivo 2000/2001. Ljuljn, Biotehnišk fkultet: 90 p. Knewitz, H., Koch, H Ws die neuen Düsen ringen? DLG-Mitteilungen, 3: Kryger Jensen, P Cn new spry techniques improve control of potto lte light? Sttus nd future possiilities. [online] URL: r_kryger.pdf/ Lešnik, M Tehnik in ekologij ztirnj plevelov. Ljuljn, Kmečki gls: 243 p. Luckhrd, J., Brune, R Krtoffel rundum schützen. Krtoffelu 4: Spry ppliction technique, British potto council. [online] URL: pry_technique2004.pdf Stlling, H., vn de Znde, J.C., Michielsen, J.M.G.P., Meier, R., Schepers, H.T.A.M., vn Velde, P., Verwijs, B Effect of spryer speed nd nozzle type on spry distriution nd iologicl efficcy in potto lte light control. Aspects of Applied Biology, 99: Stngl, J Appliktionstechnik Wie viel Wsser und welche Düse? Die fortschrichttliche Lndwirt, 19: Strsurger, E Lehruch der Botnik für Hochschulen. Stuttgrt, Jen, New York, Gustv Fischer Verlg: 1030 p. 164 Act griculture Slovenic, 99-2, septemer 2012