Keywords: apple, apple scab, carbonate, organic orchards

Transcription

1 52 Reviewed Ppers Preventtive nd curtive pplictions of crbontes ginst pple scb (Venturi inequlis) in orgnic pple orchrds M. Kelderer, C. Cser 2, E. Lrdschneider 3, A. L Torre 4 Abstrct In the EC, for long time, only copper- nd sulphur-bsed products were llowed to control vriety of diseses on different crops. However, it is well-known tht these products lso hve negtive side effects on beneficil orgnisms nd the soil. For mny yers reserchers hve been looking for lterntives to reduce their use nd /or replce them. Different crbontes hve been investigted intensively in the lst yers. They re present in nture nd were used in the pst in orgnic frming. With Decree 404/2008, Annex II of Regultion (EEC) No. 2092/9 ws updted nd potssium bicrbonte (PBC) ws included into the list of ctive substnces llowed in orgnic frming. On Jnury 2009, potssium bicrbonte ws lso included into Annex I of Council Directive 9/44/EEC concerning the plcing of plnt protection products on the mrket. Field trils crried out from 2003 to 2009 in South Tyrol evidenced n interesting efficcy of crbonte-bsed products ginst pple scb nd other diseses, but lso phytotoxic side effects emerged depending on the formultion nd the pplied rte. First results were presented in the proceedings of the 2 th nd 3 th Ecofruit conference. The results of recent field trils re presented, which imed t evluting the efficcy of different crbontebsed products in stopping further pple scb development nd thus their curtive ction. Keywords: pple, pple scb, crbonte, orgnic orchrds Introduction In the EC, for mny yers, lmost exclusively copper- nd sulphur-bsed products were llowed for the control of vriety of different fungl diseses in orgnic frming. It is wellknown tht these products cn negtively ffect the soil, beneficil orgnisms, etc. Depending on the climtic conditions during ppliction, they cn lso cuse severe dmge on leves nd fruits. For mny yers, reserchers hve therefore been looking for vluble lterntives in order to reduce their use nd/or even replce them. Crbontes were brought forwrd frequently s lterntives to copper- nd sulphur-bsed products (Grbler & Smilnick, 200; Vecchione et l., 2002; Leeson & Crips, 2004; Smilnick et l., 2004; Conwy et l., 2005; Tmm et l., 2006; Heyne et l., 2006; Pfeiffer 2008; Jmr et l., 2007). They re present in nture, nd hve lredy been used in the pst in orgnic frming. They re considered hrmless from n ecotoxicologicl nd toxicologicl point of view (EPA, 999). Since 2008 they re included into Annex II of Regultion (EEC) No. 2092/9 on orgnic production, nd in 2009 potssium bicrbonte hs lso been included into Annex I of Council Directive 9/44/EEC concerning the plcing of plnt protection products on the mrket. From 2003 to 2006, field trils with unformulted nd formulted PBCs were conducted t the Reserch Centre Limburg (South Tyrol, Itly) in order to evlute their efficcy ginst pple scb nd to record possible phytotoxic effects on the crop. Prt of the results were published in the proceedings of the 2 th nd 3 th Ecofruit-conference. (Kelderer & l M. Kelderer, VZ-Limburg, Post Auer, Südtirol, Itlien; Mrkus.Kelderer@provinz.bz.it 2 C. Cser, VZ-Limburg, Post Auer, Südtirol, Itlien; Cludio.Cser@provinz.bz.it 3 E. Lrdschneider, VZ-Limburg, Post Auer, Südtirol, Itlien; Ewld.Lrdschneider@provinz.bz.it 4 A. L Torre, C.R.A.-ISPVE, Vi C.G. Bertero, Rom, Itlien;.ltorre@ispve.it

2 Reviewed Ppers nd 2008). Of gret interest re the sttements of Kunz (2008), who observed curtive effect of crbontes ginst pple scb on potted plnts in greenhouse trils. Our studies crried out in 2008 nd 2009, imed t verifying the occurrence of curtive effect lso in the open field. Mteril nd Methods All trils were crried out in estblished pple cv Golden Delicous orchrds under integrted pest mngement (rootstock: M9) t the Reserch Centre Limburg (South Tyrol Itly). In ddition to the tretments ginst pple scb, common cultivtion prctices were used in ll study orchrds. The product nme, its ctive substnce, mnufcturer/distributor, nd the concentrtion of ctive substnce in ech product re listed in Tble. Tble : description of the products tested in 2008 nd Product nme Active substnce % Active substnce Mnufcturer/ distributor Mycosin Acid cly - Biof Cuev Cu- octnte 8 Neudorff Kocide 3000 Cu-hydroxide 5 DuPont Armicrb* K-bicrbonte (PBC) 85 H&I Agritech Bicrbonto di potssio* K-bicrbonte (PBC) 99 ACEF Vitisn* K-bicrbonte (PBC) 99 Biof Potssio crbonto K-crbonte 98 ACEF Polisolfuro di Clcio Lime sulphur 23 Polisenio Sodio bicrbonto N-bicrbonte 99 SISECAM Tiovit Jet Sulphur 80 Syngent Thiopron Sulphur 83 Cerexgri *unformulted K-bicrbonte Preventtive pplictions with motorized spryer during primry infection period (2008 nd 2009) To compre the different tretments, rndomized complete block design with 4 replictes per tretment nd with 7 trees per plot ws used. To prevent border effects, ech plot ws bounded by gurd trees nd gurd rows. Tretments were pplied with motorized spryer for experimentl trils from Wibl (trnsverse current blower), using spry volume of 500 l wter per hectre nd m folige height. Tretments were pplied immeditely before it begn to rin on dry leves from Mrch to end of My. In 2008, the durtion of lef wetness during the mjor infection periods ws extended using bovecnopy irrigtion. Scb stop pplictions with motorized spryer during the period of primry infection (2008 nd 2009) To compre the different tretments, rndomized complete block design with 4 replictes per tretment nd with 7 trees per plot ws used. To prevent border effects, ech plot ws bounded by gurd trees nd gurd rows. Tretments were pplied with motorized spryer for experimentl trils from Wibl (trnsverse current blower), using spry volume of 500 l wter per hectre nd m folige height. Tretments were pplied t 300 degree hours, followed by second ppliction fter dditionl 600 degree hours in cse

3 54 Reviewed Ppers of enduring lef wetness. As second vrint, ll four tretments were lso pplied only fter 600 degree hours. The trils lsted from Mrch to end of My. Scb stop pplictions through bove-cnopy irrigtion during primry infection period (2008 nd 2009) To compre the different tretments, rndomized complete block design with 3 replictes per tretment nd with 0 plnts per plot ws used. Ech plot ws bounded by gurd trees nd gurd rows to prevent border effects. All tretments were pplied through bovecnopy irrigtion. To ensure uniform wetting nd coverge of the vegettion within the plots, two full circle sprinklers (Kofler K0; throw distnce: 2 m; nozzle size: 3 mm) with overlpping wter jet were plced in ech plot. In 2008, tretments were pplied t 500 degree hours of lef wetness. In cse lef wetness persisted for more thn 650 degree hours, n dditionl ppliction ws mde t 900 degree hours. In 2009, tretments were pplied t 300 degree hours, nd were repeted fter dditionl 300 degree hours in cse of enduring lef wetness. Tretments were pplied until the end of My. Preventtive pplictions with motorized spryer during secondry infection period (2009) This tril ws crried out only in To compre the different tretments rndomized complete block design with 4 replictes per tretment nd with 7 trees per plot ws used. To prevent border effects, ech plot ws bounded by gurd trees nd gurd rows. Tretments were pplied with motorized spryer for experimentl trils from Wibl (trnsverse current blower), using spry volume of 500 l wter per hectre nd meter folige height. The entire orchrd ws treted extensively during the primry infection period in order to estblish high pple scb pressure during the secondry infection period. The orchrd ws treted on weekly bsis from the end of June until the end of August. Assessments In ll trils the incidence of pple scb on leves nd fruits ws ssessed twice, t the end of the primry infection period nd in utumn t hrvest, respectively. In 2008, in ddition, percent fruit russeting ws ssessed. In 2009, for the preventtive pplictions during the secondry infection period, we lso ssessed for percent lef drop (visul ssessment ccording to scle rnging from 0 to 0) nd fruit russeting t hrvest. To ssess for fruit russeting, in ech plot, t hrvest, fruits were checked for symptoms of fruit russeting nd clssified ccording to scle rnging from 0 to 0, with 0 = fruit with no russeting symptoms, = fruit with russeting symptoms t stlk cvity, 2 = fruit with 0-20% fruit re ffected by fruit russeting, nd so on. The percentge of fruits with fruit russeting index bove 3 ws then clculted nd indicted in the tbles s % fruit russeting. In this tril, we lso determined the proportion of spider mites vs predtory mites present t hrvest, by counting the number of spider mites nd predtory mites on rndomly selected leves. Sttisticl nlysis All dt were compred cross tretments using -wy ANOVAs followed by Student- Newmn-Keuls test for posthoc comprisons of mens (P<0.05). To improve homoschedsticity, dt expressed in percentges were rc sin (rdq(x/00)) - trnsformed. All nlyses were performed with the sttistics progrmme PASW 7.

4 Reviewed Ppers 55 Results Tril 2008: Preventtive pplictions with motorized spryer during primry infection period Tble 2: Percentge of leves nd fruits infected by pple scb nd percent fruit russeting in the different tretments Product Applied rte (g/hl) % ffected leves % ffected fruits % fruit russeting Kocide Cu met b bc Cuev 0 Cu met c Mycosin c 94.5 b 3.2 Armicrb d 00.0 b 34.7 bc PBC d 00.0 b 25.7 bc PBC d 98.5 b 39.0 bc PBC d 97.5 b 4.2 bc PC cd 97.0 b 43.3 bc NBC c 96.0 b 22.2 b Polisenio b 86.0 b 9.0 Control d 00.0 b 32.7 bc percentge of fruits with more thn 30 % russeted fruit surfce re 2 not formulted As mentioned bove, the durtion of lef wetness during the mjor infection periods ws extended using bove-cnopy irrigtion, which resulted in extremely high disese pressure. In fct, in the untreted control lmost ll leves nd fruits were infested by pple scb (Tble 2). Disese incidence on leves ws significntly lower for the copper-bsed tretments (Kocide 3000 nd Cuev) nd for the stndrd Lime sulphur thn for ll the other tretments. On fruits, differences mong tretments were even less mrked. Fruit russeting ws lowest on fruits treted with Mycosin nd Lime sulphur. Tril 2008: Scb stop pplictions with motorized spryer during the period of primry infection Tble 3: Percentge of leves nd fruits infected by pple scb nd percent severe fruit russeting in the different tretments Product DH (g/hl) leves fruits fruits 2 Applied rte % ffected % ffected % russeted Polisenio ,8 5,5 7,6 Polisenio ,8 7,5 b 6,8 PBC + Tiovit ,0 b 24,5 b 4,0 PBC + Tiovit ,8 c 5,5 bc 7,5 PC + Tiovit ,7 b 42,9 bc 9,5 PC + Tiovit , b 46,4 bc 0,2 Mycosin + Tiovit ,4 d 67,4 bcd 9,2 Mycosin + Tiovit ,4 d 8,2 cd 0,3 Control ,9 e 89,7 d 3,6 Degree hours fter onset of rin 2 percentge of fruits with more thn 30% russeted fruit surfce re 3 not formulted

5 56 Reviewed Ppers Also in this tril, disese pressure ws extremely high (90% fruits ffected by pple scb in the untreted control; Tble 3). The tretments hd been pplied on wet leves t the degree hours (DH) fter onset of rin indicted in Tble 3. Best results were chieved with Lime Sulphur (Polisenio) pplied t 300 DH fter the onset of rin, with efficcy vlues of pproximtely 94.0% in reducing both disese incidence on leves nd fruits. Also when pplied t 600 DH fter the onset of rin, Lime sulphur provided good disese control. The two tested crbonte-bsed products (PBC nd PC) showed only prtil efficcy in suppressing pple scb. Tril 2008: Scb stop pplictions through bove-cnopy irrigtion during primry nd secondry infection period Product DH PBC + Tiovit Tble 4: Percentge of leves nd fruits infected by pple scb nd percent fruit russeting in the different tretments (g/hl) leves fruits % russeted fruits 2 App. rte % ffected % ffected Polisenio ,8 4,7 38, ,5 + 4,5 c b , 52,0 49,9 Mycosin ,3 89,3 33,9 Tiovit ,5 d b PC + Tiovit b b ,8 28,7 60,3 Control ,0 d 94,0 b 43,6 b Degree hours fter onset of rin 2 percentge of fruits with more thn 30% russeted fruit surfce re 3 not formulted Also when pplied with the bove-cnopy irrigtion system, Lime sulphur (Polisenio) provided effective disese control under conditions of high disese pressure (men efficcy: 86.0% on leves nd 84.4% on fruits; Tble 4), while lower efficcy vlues were obtinedwith the two crbontes. Tril 2009: Preventtive pplictions with motorized spryer during primry infection period Tble 5: Percentge of leves nd fruits infected by pple scb in the different tretments Product Applied rte (g/hl) % ffected leves % ffected fruits Polisenio b 4.9 Thiopron b 4.0 Tiovit d 6.0 Kocide Tiovit 0 Cu met Vitisn + Tiovit b 7.4 Mycosin + Tiovit b 2.5 Control e.7 b not formulted Differences mong tretments pplied preventtively with the motorized spryer during the primry infection period, were less evident in 2009 thn in Best disese control on

6 Reviewed Ppers 57 leves ws recorded for the copper-bsed product Kocide 3000 (0 g pure copper/00 l), followed by Lime Sulphur (Polisenio), Tiovit pplied in tnk mixture with the cid cly Mycosin, nd finlly by the tnk mixture Vitisn plus Tiovit. Disese incidence on fruits ws significntly lower in treted thn in untreted control plots, with differences mong treted plots not being significnt. Tril 2009: Scb stop pplictions with motorized spryer during the period of primry infection Tble 6: Percentge of leves nd fruits infected by pple scb in the different tretments Product DH Applied rte (g/hl) % ffected leves % ffected fruits Polisenio , b,5 Polisenio ,7 bc 2,5 bc Thiopron ,8 c 8,2 c Thiopron ,2 c 6, c Tiovit ,0 c 6,4 c Kocide Tiovit Cu met ,4 c 2,5 bc Kocide Tiovit Cu met ,6 c 5,0 c Vitisn 2 + Tiovit , 2,2 b Control , c 0,7 c Degree hours fter the onset of rin 2 not formulted Also the results obtined in 2009 with curtive pplictions with the motorized spryer differed from those observed in Highest efficcy on leves ws recorded for unformulted PBC (Vitisn) nd Lime sulphur (Polisenio), nd similr results were obtined on fruits. Tril 2009: Scb stop pplictions through bove-cnopy irrigtion during primry infection period Tble 7: Percentge of leves nd fruits infected by pple scb in the different tretments Product DH Applied rte (g/hl) % ffected leves % ffected fruits Polisenio ,5 3,3 0,9 Thiopron 300 8,4 43,4 bc 3,8 bc Tiovit 300 6,3 52, bc 4,3 bc Vitisn 2 + Tiovit ,3 35,6 b 3,3 b Control , c 26,5 c Degree hours fter the begin of the rinfll 2 not formulted When the products were pplied with the bove-cnopy irrigtion, insted, the results recorded in 2009 confirmed those obtined in 2008: the efficcy of Lime sulphur (Polisenio) in reducing pple scb incidence on leves mounted to 76.6%, while tht of unformulted PBC (Vitisn) pplied in tnk mixture with Tiovit did not exceed 38%. However, both tretments provided comprble disese control on fruits.

7 58 Reviewed Ppers Tril 2009: Preventtive pplictions with motorized spryer during secondry infection period Tble 8: Percentge of leves nd fruits infected by pple scb; percentge of lef drop, proportion spidermites/predtory mites nd percent severe fruit russeting in the different tretments Product spidermites/ russeting Applied rte % ffected % (g/hl) fruits lefdrop predtory index mites Mycosin + Tiovit b b 9.7 Ulmsud + Tiovit b b 9.0 Rocksil + Tiovit b Armicrb b 20.0 b Vitisn + Tiovit + TS Forte b Vitisn + Tiovit Thiopron b Polisenio Control b 8.8 b not formulted The highest pple scb incidence reduction with preventtive pplictions during the secondry infection period ws recorded for the tnk mixture Vitisn + Tiovit, followed by the tnk mixture Vitisn + Tiovit + TS Forte (Tble 8). However, the ltter tretment resulted in considerble lef drop. A significnt increse in the proportion spider mites/predtory mites ws observed for the tnk mixtures Mycosin + Tiovit nd Ulmsud + Tiovit, but not for ny of the other tested tretments. There ws no significnt difference between the tretments concerning the fruit russeting. Discussion The trils crried out in 2008 nd 2009 imed t compring the efficcy of crbontebsed products in suppressing pple scb with tht of reference products, commonly pplied in orgnic orchrds for pple scb control. We tested both preventtive tretments nd specificlly trgeted curtive tretments. Tretments were either pplied with motorized spryer or with the bove-cnopy irrigtion system. In the two yers of trils, results were not consistent, nd to be considered conclusive, further studies re wrrnted. Possible explntions for these inconsistent results re provided below. Wether conditions in the two study differed considerbly. In 2008 high nd repeted rinflls occurred. Furthermore, the durtion of the mjor infection periods ws extended with bove-cnopy irrigtion, nd disese pressure ws therefore extremely high. Almost 00% pple scb incidence on leves nd fruits in the untreted control). When pplied both preventtively nd curtively, the efficcy ginst pple scb of the crbonte-bsed tretments ws lwys considerbly lower thn tht of the reference Lime sulphur tretment. In 2009, insted, reltively dry wether conditions occurred during the primry infection period. Higher thn verge spore flight took plce during this infection period (7 th, 20 th, 27 th nd 30 th of April). Furthermore, no hevy rinflls occurred during the primry infection period. Ninety percent of the pple scb spots on leves originted from this infection period (64,3mm). Since the leves dried immeditely, it ws impossible to pply the tretments onto wet leves, s originlly plnned. The crbonte-bsed tretments nd the stndrd Lime sulphur provided similr results in both the preventtive

8 Reviewed Ppers 59 trils (primry nd secondry infection period) nd in those where tretments were specificlly trgeted with the motorized spryer, while they did not when tretments were pplied with bove-cnopy irrigtion. In this cse, the efficcy of Lime sulphur ws considerbly higher thn tht of the crbontes. Differences between 2008 nd 2009 existed lso in the mount of sulphur dded to the tnk mixtures. In 2009, in the preventtive trils, the crbontes were pplied in tnk mixture with sulphur-bsed product, but not in 2008, nd the mount of sulphur dded to the tnk mixture in 2009 in the curtive trils ws much higher thn tht used in Previous studies with Armicrb (Kelderer et l nd 2008) hve shown tht formultion cn definitely ffect the efficcy of the product. Given the results obtined in our trils under different climtic conditions nd with the different product combintions, the following ssertions cn be mde: An pproprite formultion is n essentil condition for the efficcy of crbontes, nd, pprently, by dding sulphur-bsed product t high rte this requirement cn be met. The efficcy of other tnk mixtures must still be evluted. The ddition of oily substnces my result in incresed lef drop nd fruit russeting (Tble 8). Crbontes must rech the leves t n dequte rte. When pplied during rinfll or with bove-cnopy irrigtion, the ctive substnce retined on the leves is not enough to ensure effective disese control. To deepen our knowledge on this spect, dose-response studies for preventtive nd curtive pplictions in comprison to Lime sulphur re needed. Acknowledgements This project ws finncilly supported by the Itlin Ministry of Agriculture nd Forestry (Mipf) (Ministeril Decree no. 956 of 5/09/05, studies iming t complince with the limits for copper by using either formultions with low copper content or lterntive tools). References Conwy W.S., Leverentz B., Jnisiewicz W.J., Blodgett A.B., Sftner R.A., Cmp M.J. (2005): Improving biocontrol using ntgonist mixtures with het nd/or sodium bicrbonte to control posthrvest decy of pple fruit. Posthrvest Biology nd Technology 36(3), EPA (999): potssium bicrbonte in Biopesticide Active Ingredient Fct Sheets. URL: Grbler F.M. & Smilnick J.L. (200): Posthrvest control of tble grpe grey mold on detched berries with crbonte nd bicrbonte slts nd disinfectnts. Americn Journl of Enology nd Viticulture 52(), Heyne,P.Krusse,P.& Mxin,P.(2006) First experiences with bicrbonte ginst scb in Hmburg. Proceedings of the 2th Interntionl Conference on cultivtion technique nd phytopthologicl problems in orgnic fruit-growing, ed. FÖKO e.v. (FÖKO e.v., Weinsberg), Jmr, L., Lefrncq, B., & Lteur, M. (2007) Control of pple scb ( Venturi inequlis ) with bicrbonte slts under controlled environment. Journl of Plnt Disese nd Protection 4, Kelderer M. (2006). First results of the use of potssium bicrbonte ginst scb in South Tyrol. Proceedings of the 2th Interntionl Conference on cultivtion technique nd phytopthologicl problems in orgnic fruit-growing, ed. FÖKO e.v. (FÖKO e.v., Weinsberg), Kelderer M.; Cser C., Lrdschneider E. (2008): Formulted nd unformulted crbontes to control pple scb (Venturi inequlis) on orgnic pple. 3th Interntionl Conference on

9 60 Reviewed Ppers Cultivtion Technique nd Phytopthologicl Problems in Orgnic Fruit-Growing. Fördergemeinschft Ökologischer Obstbu e. V. Weinsberg, Kunz S., Mögel G., Hinze M., Volk F. (2008): Control of pple scb by curtive pplictions of biocontorl gents. 3th Interntionl Conference on Cultivtion Technique nd Phytopthologicl Problems in Orgnic Fruit-Growing. Fördergemeinschft Ökologischer Obstbu e. V. Weinsberg, (2), 8-20 Leeson G.R. & Crips P. (2004): Food dditive s n orgnic fungicide for powdery mildew Ecocrb. Act Horticulture 648, Pfeiffer, B. (2008): Results from scb trils with Armicrb in the yers 2006 nd Proceedings of the 3th Interntionl Conference on cultivtion technique nd phytopthologicl problems in orgnic fruit-growing, ed. FÖKO e.v. (FÖKO e.v., Weinsberg), 4-46 Rühmer, T. (2007): personl communiction Smilnick J.L., Mrgosn D.A., Mlikot F., Usll J., Michel I.F (999): Control of citrus green mold by crbonte nd bicrbonte slts nd the influence of commercil posthrvest prctices nd their efficcy. Plnt Disese 83(2), Tmm, L., Amsler, T., Schärer H., Refrdt M. (2006): Efficcy of Armicrb (potssium bicrbonte) ginst scb nd sooty blotch on pples. Proceedings of the 2th Interntionl Conference on cultivtion technique nd phytopthologicl problems in orgnic fruit-growing, ed. FÖKO e.v. (FÖKO e.v., Weinsberg), Vecchione A., Luc F. de, Snnicoló M., Pertot I. (2002): Efficcy of some nturl compounds ginst strwberry powdery mildew. Atti Giornte fitoptologiche 2,