EPIDEMIOLOGY AND MANAGEMENT OF WALNUT BLIGHT

Transcription

1 EPIDEMIOLOGY AND MANAGEMENT OF WALNUT BLIGHT J. E. Adskveg, H. Förster, D. Thompson, J. Enns, J. Connell, nd R. Buhner Cooperting: L Wde, Aryst LifeSienes ABSTRACT The inidene of wlnut light in 2009 ws low to moderte t most lotions euse environmentl onditions in the spring were low to modertely onduive for the disese. Still, dt were otined on the evlution of new teriide tretments for wlnut light in seven field trils tht were onduted with or without the pplition of simulted rin. This yer's studies gin indited tht opper-ebdc tretments re the most onsistent tretment in ontrolling wlnut light in Cliforni. Two formultions of the oordinted EBDC mnoze, dry flowle (DF) nd flowle (F), were evluted s replements for the reently (2009) nelled mne tht ws registered nd mrketed s Mnex. In most trils, Mnzte ws similrly effetive s Mnex. Thus, this effiy dt supports the emergeny registrtion of mnoze s Mnzte nd its full registrtion inluding other produts suh Dithne nd Pennoze s replements of mne. Severl opper produts (i.e., opper hydroxide, opper oxyhloride) were lso evluted inluding Koide 3000 nd Kentn DF, s well s newly registered opper produts suh s Bdge SC nd Bdge X2 (oth ontining mixtures of opper oxyhloride nd opper hydroxide). Newly formulted opper mterils, i.e., Koide 3000 nd Bdge produts, ontin lower metlli opper equivlents (30 nd 28%), respetively, nd n e pplied t lower rtes per re thn previous produts nd still re highly effiious s ompred to other produts tht require higher mounts of opper. Thus, these tretments re step in reduing opper usge nd llowing wlnut light mngement to hve less impt on the environment. Among new lterntive tretments evluted, ksugmyin (Ksumin) is one of the top-rted lterntives tht demonstrted very good to exellent effiy when pplied in omintion with opper or n EBDC mteril. The effiy of the ntiioti-ebdc omintion ws equivlent or etter thn opper-ebdc tretments in orhrds where opper resistne hs ourred. Ksugmyin ws sumitted to the IR-4 progrm in 2006, field studies hve een ompleted, nd the proposed registrtion hs een sumitted to EPA with federl registrtion expeted in 2011 nd Cliforni registrtion y This ntiioti represents the first new ntiioti in US griulture in more thn 40 yers nd the first lterntive to opper in the mngement of wlnut light. In ddition, severl produts were evluted tht ould potentilly e used in orgni prodution. Atinovte ( fermenttion produt ontining the tinomyete Streptomyes lydius) nd Cereroide (n extrt of shiitke mushrooms) showed promising results in severl trils in Regli (n extrt of Reynoutri shlinensis) lso performed well in reduing light in some trils where disese pressure ws reltively low in 2008 nd These mterils were less effetive under higher disese levels (>12-14%) inidene) nd thus, were inonsistent when ompred to the performne of opper-ebdc mixtures. As in previous yers, our reserh demonstrted tht the mngement of wlnut light requires mngement progrms tht use omintion of teriide pplitions sed on host phenology (i.e., tkin or pistillte flower emergene - ud rek stges) nd environmentl onditions (moderte to high preipittion, lef wetness nd moderte tempertures) tht hve een quntified using n epidemiologil model (i.e., XnthoCst) tht forests fvorle Cliforni Wlnut Bord 241 Wlnut Reserh Reports 2009

2 environmentl onditions for disese development. Miniml spry progrms of one to two pplitions of opper-ebdc t the eginning of femle flowering hve een repetedly demonstrted s inonsistent nd hve led to higher disese inidene lter in the seson nd in susequent sesons. XnthoCst indies hve een suessfully orrelted to light development nd they hve een experimentlly verified in simulted-rin studies nd under mient onditions in sttewide (regionl) nd yerly evlutions. Thus, the use of XnthoCst optimizes timing of teriides nd disese ontrol while minimizing the totl numer of pplitions. Additionl refinements to the model inlude dew point tempertures nd high temperture limits in determining teriide pplitions. Long-term gols in light mngement inlude the development of wlnut light-resistnt vrieties from genotypes identified s less suseptile in our simulted rin, sreening progrms. INTRODUCTION Wlnut light, used y Xnthomons xonopodis pv. juglndis (formerly X. juglndis), is mjor disese of wlnut in entrl nd northern Cliforni. The pthogen infets tkins, femle lossoms, green shoots, leves, uds, nd fruit of English wlnut with fruit infetions ounting for most of the eonomi loss. Infetions ommonly our in the spring under wet onditions. The terium survives from one yer to the next in helthy nd disesed uds, disesed fruit tht remin on the tree, nd possily in twig lesions (Miller nd Bollen 1946; Mulren nd Shroth 1982; Teviotdle et l. 1985, Ogw nd English 1991). For mngement of wlnut light, short- nd long-term gols inlude properly timed teriidl tretments inluding iologil produts for orgni growers nd the use of nturl host resistne in reeding progrms, respetively. Both spets hve een fous of our reserh over the yers. New effetive opper-sed nd non-opper-sed teriides hve een identified nd our disese foresting model XnthoCst ssists in the proper timing of these tretments. In wlnut vriety plot we hve een rnking ultivrs nd genotypes for their disese suseptiility over severl yers. In developing mirolimte model to predit wlnut light ll omponents of the disese tringle (host, pthogen, nd environment) hve to e inorported. The host omponent in the tringle is defined y the phenologil stge of development nd y differentil host resistne mong wlnut ultivrs. In the pthogen omponent, inoulum ppers to e the most preditle prmeter to estimte euse the pthogen is endemi in estlished wlnut orhrds throughout Cliforni nd hs high reprodutive potentil under fvorle environments. The environmentl omponent ritilly determines the disese risk nd is defined y the ontinully hnging wetness nd temperture onditions during the spring seson. Bsed on nlyses of environmentl dt nd tul disese progression over severl sesons t severl lotions, we developed XnthoCst s model to predit infetion periods for wlnut light. This umultion model utilizes wetness period durtion nd temperture prmeters otined from wether sttions. Irrigte.net nd Agtelemetry.om provide the si XnthoCst informtion with n up to five-dy wether forest nd predition of XnthoCst indies for individul wether sttions etween Red Bluff nd Dvis to ny grower, PCA, or frm dvisor. The XnthoClultor llows individul we-sed foresting for different grower fields nd lotions. As onfirmed y us nd IPM speilists, the foresting model redues the totl numer of pplitions while mintining the sme level of mngement s lendr-sed progrm. The XnthoCst system offers flexiility to hnges in the miro-environment during eh seson nd Cliforni Wlnut Bord 242 Wlnut Reserh Reports 2009

3 is very roust progrm tht provides regionl- or grower-speifi forests, judiil use of pestiides, nd disese ontrol similr to lendr-sed progrms. In ongoing studies eh yer, the model is eing vlidted under different limti onditions, e.g. highly onduive nd less fvorle disese onditions. Field studies in 2009 foused on timings nd totl numer of teriide tretments tht re neessry for providing high level disese ontrol. In sesons with low rinfll nd unfvorle tempertures, one or two erly-seson (loom) pplitions should e followed up with mid- to lte seson pplition round fvorle environmentl event (i.e., s predited y XnthoCst) to provide disese ontrol nd to redue pthogen popultions for the following seson, wheres in sesons with more rin nd fvorle tempertures, dditionl post-loom pplitions re neessry. In severl trils using miniml spry progrms, we demonstrted tht single lowgllonge (100 gl/a) ud-rek pplition with Koide-EBDC (with or without Brekthru) did not stisftorily ontrol the disese nd resulted in epidemis espeilly when wetness ourred fter loom. The erly-seson tretments should e sed on phenology nd on rin events euse tkin teriide pplitions were enefiil during erly loom in wet sesons. Furthermore, dews my provide enough wetness etween the ud sles to retivte overwintering teri tht n initite infetions. Our gol hs een to develop mngement progrm where loom pplitions re sed on lossom phenology desriing ud rek stges of loom (i.e., tkin CFE nd pistillte flower emergene PFE ) nd environmentlly-sed XnthoCst forests. Thus, protetive loom nd susequent tretments during fruit development re sed on predited imminent rin or wetness events nd fvorle tempertures to prevent new infetions. Perpetul, over-usge of opper-sed produts for wlnut light mngement over severl dedes hs resulted in opper-resistnt popultions of the pthogen nd environmentlly unsustinle progrms (higher usge rtes nd more frequent pplitions). Thus, there is need for lterntive tretments nd improved pplition methods. The introdution of opper-mne tretments y Conover nd Genhold (1981) with the pplition of two tive ingredients hs improved the effiy of fixed opper tretments ginst opper-resistnt pthogen popultions. Furthermore, new formultions of opper-sed produts tht we tested in previous yers hve lower usge rtes when used in omintion with EBDC (e.g., mne or mnoze) tretments. Thus, we ontinued our evlutions of new opper mterils in 2009 nd inluded Koide 2000, Koide 3000, Kentn (ll opper hydroxide), nd Bdge X2 nd SC (mixtures of opper oxyhloride nd opper hydroxide). The EBDC mterils Mnzte (mnoze; oordintion produt of zin ion nd mngnese ethylene is-dithiormte), nd Mnkoide ( pre-mixture of Koide nd mnoze) were evluted euse of the nelltion of mne (Mnex; mngnese ethylene is-dithiormte). Beuse of the development of opper-resistnt pthogen popultions nd euse of environmentl onerns regrding over-use of opper, mngement of wlnut light is lso dependent on the development of new teriidl tretments with different modes of tion. Numerous potentil lterntives hve een evluted y us over the yers with results rnging from ineffetive or inonsistent, wekly to modertely effetive; or the mteril ould not e registered. The ntiioti ksugmyin (Ksumin - Aryst Life Sienes) is registered for griulturl use for mnging plnt diseses used y fungi nd teri in Jpn. This lss of ntiiotis is not eing used in humn nd niml mediine, hs different mode of tion from Cliforni Wlnut Bord 243 Wlnut Reserh Reports 2009

4 streptomyin or terrmyin, nd there is no ross-resistne known to our. In our previous yers trils we otined very good to exellent results with ksugmyin ginst wlnut light. Bsed on our reserh, ksugmyin ws sumitted to the IR-4 progrm, field studies re ompleted, nd registrtion is in progress. This ntiioti ws gin inluded into our 2009 trils either y itself or in seleted mixtures. Ksugmyin/EBDC or /opper omintions re expeted to e exellent lterntives or rottionl tretments for mnging wlnut light. In ddition, we evluted severl nturl ompounds inluding Regli nd Cereroide, s well s Atinovte ioontrol tht ontins the tinomyete Streptomyes lydius. Additionlly, the plnt stress response induer BioForge nd ReZist tht ontins plnt nutrients tht re thought to e importnt in plnts to mintin their helth nd vitlity under dverse onditions were evluted s potentil tretments to mnge wlnut light. OBJECTIVES I. New tretments - Evlute the toxiity of lterntive opper (i.e., Kentn, Bdge, nd the low-opper-onentrtion produt Koide 3000) nd non-opper sed hemils (e.g., the ntiioti Ksumin, EBDC fungiides, new nturl produts formultions of Regli, Cereroide), numered iologils (e.g., Atinovte), nd other experimentl mterils suh s enhners of plnt stress response (e.g., BioForge, ReZist, et,) ginst X. juglndis nd evlute the effiy of these mterils for mnging wlnut light in lortory nd smll-sle field tests s ompre to fixed-opper ompounds. Crop destrution osts will e inluded in udget. A) Comprtive effiy of new teriides (syntheti nd nturl produts) using irlst spry pplition methods in field trils under mient nd simulted rin systems t the Kerney AgCenter (KAC), UC Dvis, nd in ommeril orhrds in Butte Co. B) Studies using mixtures of opper or ksugmyin with EBDC fungiides (e.g., Mnzte, Dithne). II. Epidemiology - Continue to evlute disese development throughout the spring nd monitor environmentl prmeters (e.g., lef wetness, preipittion, temperture, nd reltive humidity) tht re onduive to teril infetion of wlnut tissues using dtloggers nd CIMIS dt. (This will e done in orhrds with other ongoing light reserh progrms). A) Develop nd evlute preipittion-temperture-sed version of XnthoCst (ongoing) in oopertion with UC-IPM nd CIMIS progrms for utilizing lef wetness dt nd dew point temperture for XnthoCst to e used on university wesites. B) Evlute erly, mid-, nd lte-spring timings (e.g., mle (tkin) vs. femle (pistillte) flower emergene or delyed emergene in respet to Bloom Cyle, s well s mid- to lte spring seson timings) under nturl nd simulted rin environments. C) Continue to determine the reprodution potentil of the pthogen on the plnt surfe using spirl plting tehnology. D) Evlute previous yers disese levels s generl inditor for strt time for using the XnthoCst model. III. Host resistne - Continue to evlute wlnut genotypes for nturl host resistne to wlnut light under simulted rinfll onditions t KAC. Cliforni Wlnut Bord 244 Wlnut Reserh Reports 2009

5 PROCEDURES Evlution of lterntive teriides for mngement of wlnut light in field studies. Seven trils were estlished in experimentl orhrds in Fresno Co. (Kerney Agriulturl Center) nd Solno Co. (UC Dvis), nd in ommeril orhrd in Sutter Co. In Fresno Co., trils were onduted on vs. Chio nd Chndler. Simulted rin ws pplied in these orhrds for 6-8 h fter eh of the four or five teriide pplitions. In Solno Co., trils on vs. Hrtley, Vin, nd Tulre were onduted with three to five teriide pplitions following XnthoCst indies. Six lendr-sed pplitions were done in the ommeril orhrd on v. Vin in Sutter Co. Tretments in ll trils were pplied using n ir-lst spryer (100 gl/a) nd tretment timings (i.e., dtes of pplition) re indited in Figs Inidene of disese ws sed on the numer of infeted fruit in smple of fruit for eh of four or five singletree replitions. Dt were evluted using nlysis of vrine nd lest signifint differene men seprtion proedures or generl liner model nd LSD men seprtion proedures of SAS 9.1. Evlution of miniml spry progrms sed on host phenology, lendr dtes, nd/or XnthoCst using Koide-Mnzte. Trils under nturl rinfll onditions in Solno Co. on v. Chio nd under simulted rin onditions in Fresno Co. on v. Vin were set up to design progrms to evlute nd improve timing nd to redue the totl numer of pplitions of teriide tretments. Tretment timings for one to five pplitions of Koide-Mnzte or Bdge X2-Mnzte were sed on host phenologil stges (tkin or pistillte flower emergene) nd/or XnthoCst indies. In the Solno Co. tril, XnthoCst teriide pplitions were done s infetion periods ourred fter tretments (ording to the model) nd umultion ws then delyed for 7 dys. If no infetion periods ourred, teriides were not pplied. In the Fresno Co. tril, three XnthoCst teriide pplitions were done efore eh of two, 6-8 h simulted ( urst ) rin tretments tht were done three to four dys prt. Disese inidene ws evluted in lte My in Fresno Co. nd in erly-june in Solno Co. Fruit evlutions were sed on nuts for eh of the four single-tree replitions. Dt were evluted using nlysis of vrine nd LSD men seprtion proedures of SAS 9.1. Disese progress nd environmentl monitoring in wlnut orhrds using dt from AgTelemetry nd UCIPM-CIMIS. In n experimentl orhrd in Solno Co. t UC Dvis nd in ommeril orhrd in Sutter Co., pistillte flowers of three single-tree replitions were tgged nd monitored periodilly (every 7-10 dys) for the development of wlnut light from lte-april to lte My/erly June Fruit were refully exmined for lesions nd positive evlutions were re-heked in susequent evlutions nd in isoltions of su-smples of infeted fruit. Disese inidene ws determined s the numer of infeted fruit per totl fruit smple minus the missing fruit. Using the Irrigte.Net or AgTelemetry.om networks, nd CIMIS in the Srmento nd Sn Joquin vlleys, dew point temperture, ir temperture, reltive humidity, nd rinfll were monitored. Environmentl dt were downloded nd summrized s hourly nd dily summries from seleted sites. Dew point temperture is eing evluted s n dditionl prmeter for the XnthoCst model. Dt were grphed into figures using 7-dy indies, host phenology, nd dew point periods (3 onseutive dys of dew) s dily vlues for seleted sttions nd ultivrs. Cliforni Wlnut Bord 245 Wlnut Reserh Reports 2009

6 In n ongoing projet, we ollorted with AgTelemetry.om to llow XnthoCst V.481 to e used with the ompny s network of wether sttions in northern Cliforni. The wesite lso provides XnthoCst 4-dy forested indies of the model to llow plnning for protetive teriide pplitions. The model lultes foresting index sed on durtion of lef wetness t three temperture sles using environmentl dt from eh wether sttion. The wesite lso llows users to nme nd store their dt for individul lotions using suroutine lled XnthoClultor. With this, wether monitoring for individul wlnut ultivrs nd their phenology over diverse geogrphil rnges n e done. The disese forest for eh site is 14 to 21 dys in dvne of tul disese development sed on ltent period for disese expression fter infetion hs ourred. This is the model tht hs een desried in previous reports. Thus, we followed the model in ommeril orhrd ner Rio Oso where teriide tril ws lso done. In this orhrd, high-ngle impt sprinklers nd movle pipe system were used for irrigtion eginning in lte April. Disese evlutions of wlnut genotypes in vriety lok t the Kerney AgCenter (KAC). Wlnut genotypes seleted in the wlnut reeding progrm under Dr. Chuk Leslie nd plnted in vriety lok loted t KAC were evluted for disese inidene under simulted-rin onditions. Nturl host resistne to wlnut light ws evluted fter six weekly 8-h simulted rin events using n impt sprinkler irrigtion system. These irrigtion periods provided lef wetness ross ll loom stges (tkins nd pistillte flowers) nd erly fruit development of the ultivrs evluted. Fifty to one hundred nd thirty fruit on eh of four to five single-tree replitions were evluted for light. Dt were nlyzed using ANOVA nd LSD men seprtion proedures of SAS version 9.1 nd ompred to previous yers results. RESULTS AND DISCUSSION Wether onditions t tril sites in 2009 nd wesites for XnthoCst. Due to generlly low rinfll nd either low or high tempertures in the spring of 2009, environmentl onditions for wlnut light were low to modertely fvorle t most lotions. At the Fresno Co. tril site (Prlier, CA), 8.8 mm of rinfll ourred from Mrh 15 to My 31, 2009 (s ompred to 12.8, 25.5, nd mm in 2008, 2007, nd 2006, respetively). At the Solno Co. tril site, 61.8 mm of rinfll ourred during this period (s ompred to 32.6, 53.6, nd mm in 2008, 2007, nd 2006, respetively) nd t the Sutter Co. tril site, 44.5 mm of rinfll ourred (s ompred to 2, 58.8, nd mm in 2008, 2007, nd 2006, respetively). Simulted rin from sprinkler irrigtion tht ws used in the Fresno Co. plots to indue the disese, however, with dily high tempertures reltively high nd rehing over 30C y mid-april nd My, the numer of infetion periods in the spring seson ws redued s ompred to other yers. This resulted in lower disese levels this yer s ompred to lst yer. In the northern Cliforni trils, disese levels were higher in ll trils s ompred to lst yer. The different disese inidenes tht developed in our tril lotions over the yers support our epidemiologil understnding of wlnut light in tht the mgnitude of light epidemis is not only determined y the level of ud popultions of the pthogen t the eginning of the seson (the result of the previous yer s disese), ut y urrent-seson environmentl onditions (i.e., temperture nd wetness) tht llow for the pthogen to inrese popultion size nd hve gret impt on the sesonl development of the disese on suseptile nd erly looming ultivrs. Cliforni Wlnut Bord 246 Wlnut Reserh Reports 2009

7 XnthoCst ws gin provided y Irrigte.Net ( nd AgTelemetry ( for the wlnut distrits in northern Cliforni. Fourteen wether sttions provided mirolimte dt nd XnthoCst indies from Red Bluff to S. Dvis in the Srmento vlley. Fox wether ws ommissioned to develop in oopertion with these wesites one- to fourdy utomted forests of site-speifi lef wetness, temperture, nd XnthoCst indies to help users in mking deisions on foresting the disese. Evlution of lterntive teriides for mngement of wlnut light. Copper mterils, EBDC fungiides, ntiiotis, enhners of plnt stress response, ioontrol gent, nd nturl produts were evluted for mnging wlnut light in field studies. These produts were used lone or in mixtures. Overll, mixtures of opper mterils with n EBDC resulted in the highest nd most onsistent ontrol of wlnut light. Still, lterntives tht provided good ontrol effiy t the tril sites where often high disese pressure previled (sometimes indued y using simulted rin tretments) were identified. Among the oppers (ll in omintion with n EBDC) tht were evluted in omprisons, Koide 2000 (6 l), Koide 3000 (4 l), nd Bdge X2 (4 l) performed similrly in UC Dvis tril where 22.1% disese ws oserved in the untreted ontrol (Fig. 1). In nother tril in Solno Co. with 11.3% disese inidene in the ontrol, Kentn (5.25 l) ws similrly effetive s Bdge X2 nd Koide 2000, ut Koide 3000 ws somewht less effetive (Fig. 2). In the Sutter Co. tril with very high disese pressure (72.8% disese in the ontrol), Bdge SC, Kentn, nd Koide 3000 were ll highly effetive, reduing disese to n inidene of 5.6% or less (Fig. 3). The EBDC Mnzte pplied y itself provided intermedite ontrol in some trils (Figs. 2, 3, 4), ut ws not very effetive in nother tril in Fresno Co. where simulted rin ws pplied (Fig. 5). In this ltter tril, the Koide 3000-Mnzte mixture lso ws not very effetive, wheres in other trils it improved the effiy of opper (Figs. 3, 4). An explntion for the ineffiy of Mnzte in the Fresno Co. tril is tht this mteril is not very esily suspended in wter nd possily the mteril did not mix well in the pplition equipment without mehnil gittion tht ws used in this tril. The opper-ebdc pre-mixture Mnkoide ws only very effetive when pplied t the higher 8-l rte (Figs. 2, 4). The ntiioti ksugmyin (Ksumin), when pplied lone, signifintly redued the inidene of disese in two trils in Fresno nd Solno Co. (Figs. 2, 3, 5) nd the effiy ws similr to opper-ebdc (Fig. 2), opper lone (Fig. 3), or Mnzte lone (Fig. 3). In nother tril in Solno Co., disese inidene ws numerilly, ut not signifintly, redued from tht of the ontrol (Fig. 4). In omintion with n EBDC, ksugmyin ws eqully effetive s when pplied lone (Figs. 2, 3, 4), wheres in omintion with opper mteril the effiy of the ntiioti ws not ffeted (Figs. 2, 5) or ws inresed (Figs. 3, 4). Thus over the yers of evlution, lthough often not s effetive s opper-ebdc tretments, ksugmyin or ksugmyin mixtures hve een shown to e vlid wlnut light tretment lterntives tht, one registered, should e inluded into sesonl rottion progrm to redue opper nd EBDC use nd to minimize resistne development ginst opper mterils. Ksugmyin is urrently in the registrtion proess with n expeted federl registrtion for Cliforni Wlnut Bord 247 Wlnut Reserh Reports 2009

8 The nturl produts Regli nd Cereroide oth signifintly redued the inidene of disese from the ontrol in three of the four trils (Figs. 3, 5, 6) nd they were oth eqully effetive (Figs. 3,6). In the forth tril, Regli nd nother formultion of this plnt extrt (i.e., MOI 106B) were sttistilly ineffetive ut numerilly redued the inidene of disese (Fig. 7). Regli, ut not Cereroide, ws lso shown to e effetive in our tests in Tretments with BioForge tht lso signifintly redued the inidene of light in 2008, this yer ws gin effetive in one test (Fig. 6), ut ineffetive in nother one (Fig. 7). Interestingly, in two trils this induer of plnt stress responses improved the effiy of the ksugmyin-mnzte mixture (Figs. 4, 5). ReZist tht ontins nutrients tht re thought to e importnt to mintin plnt s helth nd vitlity under dverse environments provided inonsistent results. It signifintly redued the inidene of disese in one tril where it ws evluted y itself, ut ws not s effetive s Koide-Mnzte (Fig. 7). In mixture with Koide it did not improve the tivity of Koide 3000 (Figs. 3,5) or Koide 3000-Mnzte (Fig. 3) ut numerilly improved the effiy of Koide-Mnzte in nother tril (Fig. 5). As shown in Figs. 3, 5, nd 6, the ioontrol Atinovte ws quite effetive ginst wlnut light in three trils nd lso numerilly deresed the inidene of light in nother test in Solno Co. (Fig. 7). Summrizing our evlutions of nturl produts nd ioontrols, the performne of Regli, Atinovte, nd possily Cereroide in reduing the inidene of light ws quite onsistent with 60-70% redutions when disese levels were low to moderte (<12-14%). Thus, pending dditionl evlutions, these produts ould e of interest for orgni wlnut prodution in providing rottion tretments to orgnilly pproved opper produts where opper resistnt popultions hve developed. The potentil enefits of using BioForge or ReZist for wlnut light were less ler euse of the inonsisteny in reduing light using these tretments. Evlution of miniml spry progrms with Koide-Mnzte strting t tkin nd pistillte flower development. One field tril ws done under simulted rin on wlnut ultivr Vin in Fresno Co. nd nother one under nturl rin onditions on v. Chio in the Solno Co. Studies for the evlution of spry timings in Solno Co. In the Fresno Co. tril on v. Vin every Koide 3000-Mnzte tretment ws followed y two simulted rin ursts (2 rin events 3 to 4 dys prt). With low disese levels due to the high tempertures, ll tretment timings of Koide-Mnzte or BdgeX2-Mnzte signifintly redued the inidene of disese to similr level (Fig. 8). As mentioned ove, dily mximum tempertures were higher thn 30C y mid- April nd remined high in My. This redued the totl numer of infetion periods to two (. April 5 nd April 12) for the seson s shown in the environmentl onditions grph in Fig. 8. Thus, the disese never entered into polyyli phse. The urst simulted rin did provide onduive wetness period tht ws perhps too fvorle for disese nd thus, some disese (<4%) ourred in ll the teriide tretments. In the timing tril on v. Chio in Solno Co. under nturl rinfll onditions, four pplition progrms of Koide-Mnzte were evluted with timings using one to four pplitions (Progrms 2-5) from erly pistillte loom (emergene of femle flowers), full pistillte loom, nd timings sed on XnthoCst (Fig. 9). Dily environmentl ftors (high nd low tempertures, rinfll, nd dew period) re shown in Fig 9A. XnthoCst 7-dy indies for this orhrd re shown for teriide pplition (Koide-Mnzte) progrm 4 (Fig. 9B) nd for the ontrol (no teriide pplitions) tretment (Fig. 9C). Progrm 4 demonstrtes redued Cliforni Wlnut Bord 248 Wlnut Reserh Reports 2009

9 numer of infetion periods (4 peks s opposed to 5 in the ontrol) nd redution in the intensity (i.e., lower pek heights) of the infetions periods s illustrted y the 7-dy index (Figs. 9B). The five infetion periods resulted in disese inidene of 19.5% in the ontrol (Fig. 9D). A single pplition t erly pistillte flowering (Progrm No. 2) ws ineffetive in reduing wlnut light s ompred to the ontrol (Fig. 9D). Thus, s in previous yers, we demonstrted tht multiple pplitions tht re properly timed round wetness events nd tht inluded or did not inlude tkin nd pistillte flower emergene sprys resulted in less disese thn single erditive or miniml pplition progrm tretments. Progrms 3, 4 nd 5 with three to four pplitions ll resulted in signifintly less disese thn the ontrol. Progrm 3 ws the est tretment with the lowest disese inidene of 1.6%. This progrm hd timed one of the pplitions on immeditely fter the lrgest infetion event of the seson, wheres progrms 4 nd 5 did not inlude this timing (Fig. 9D). Thus, during this lrge infetion event with totl of 16.5 mm of preipittion, the teriide tretment my hve een lrgely removed nd the post-infetion-event pplition helped to keep the plnt tissue proteted from infetion. In ontrst, the infetion period indited y XnthoCst tht ws ssoited with with 31-mm rinfll event on My 22 pprently did not inrese disese sustntilly euse tempertures immeditely fter this rin exeeded 28C (nd rehed s high s 35C) (Fig. 9A, C). This suggests tht dditionl djustments ould e mde to the XnthoCst model if mximum disese ontrol is desired, i.e., teriide pplition fter lrge rinstorms; djustment of the temperture rnge tht is onduive for disese; nd the use of dew periods (n environmentl prmeter tht orrelted well with infetion periods Fig. 9A). Additionlly, it wrrnts the investigtion of omprison of rin-fstness mong teriide tretments. Timing of wlnut light tretments to dte n e summrized s follows: Erly pplitions t tkin nd femle flower emergene my e importnt in reduing inoulum levels ut re not self-stnding for the entire seson when dditionl rinfll my our. Comintion progrms tht inlude delyed femle (pistillte) flower emergene pplitions followed y pplitions sed on the XnthoCst environmentl model proved the most onsistent disese ontrol. Osionlly, strting progrm t tkin flowering n e enefiil. This is most likely explined y ud popultions of the pthogen nd environmentl onditions t the eginning of the seson tht llow for high teril popultions t erly femle flowering (pistillte flower emergene). Susequent pplitions during fruit development redue fruit infetions nd minimize pthogen popultions from inresing nd thus, these tretments redue disese from mid-to lte spring nd minimize re-ontmintion of developing uds y the pthogen. One dily high tempertures exeed 28C, dditionl teriide pplitions my not e neessry even when preipittion is forested. Cliforni Wlnut Bord 249 Wlnut Reserh Reports 2009

10 Disese progress nd environmentl monitoring in wlnut orhrds using dt from AgTelemetry nd CIMIS. Environmentl onditions nd disese progress were monitored in n orhrd in Sutter Co. nd re shown in Fig. 10. This is the sme orhrd where teriide effiy tril ws onduted (see Fig. 3). Dily environmentl prmeters (preipittion, min/mx tempertures, nd dew period) nd pplition dtes of teriides re illustrted for the spring seson (Fig. 10A). Between pistillte flower emergene nd My 31, two rinfll events nd four dew periods ourred. The 7-dy XnthoCst indies indited three prolonged infetion periods during this time period (Fig. 10C). Thus, the umultive seson-long XnthoCst index rehed 55 (for this region); wheres the tul disese inidene rehed 70% (in the test orhrd). The slope of the disese progress urve inresed rpidly in this time period from lte April to My 20 (Fig. 10C). This resulted from lef wetness, high humidity (dt not shown), nd susequent dew periods tht were more onduive for disese thn predited y the XnthoCst model (Fig. 10C). When teriide progrm is followed using the XnthoClultor, one teriide is pplied, then no index vlues re umulted for 7 dys. Following the disese mngement progrm used in this orhrd (Fig. 10A), the 7-dy index is shown in Fig 10B. This illustrtion shows the redued numer of infetion periods (1 pek s opposed to 3 in the ontrol see Fig 10C) nd redution in the intensity (i.e., lower pek heights or no peks) for the infetions periods ourring pproximtely on April 22 nd My 6 (Fig. 10B). Disese evlutions of wlnut genotypes in vriety lok t the Kerney AgCenter (KAC). Wlnut genotype omprisons were onduted in vriety orhrd in Fresno Co. where simulted rin ws pplied. Disese inidene mong 15 genotypes ws the highest for v. Pyne with 24% disese (Fig. 10). As shown in omprison of dt from 2005 to 2009 in this figure, this ultivr hs een the most suseptile to wlnut light in ll yers. Over the yers, PI159568, Frnquette, Cheinovo, Sinensis 5, nd PI18256 were mong the lest suseptile vrieties evluted. For others, there were some differenes in the rnking over the yers. We re urrently evluting lef surfe hrteristis of seleted vrieties tht possily ould orrelte with the oserved differenes in light suseptiility. For exmple, stomtl struture nd frequeny hs een implited in the resistne of tomto genotypes ginst infetion y Xnthomons mpestris. Our long-term gol is to provide dt on light suseptiility mong new nd old wlnut genotypes nd identify phenotypi mrkers for resistne to ssist the reeding progrm in the Hortiulture Deprtment t UC Dvis. ACKNOWLEDGMENTS Speil thnks to the grower in Sutter Co. who llowed us to ondut our reserh in his orhrd nd to the hemil industry representtives who ooperted with us with during this reserh. Cliforni Wlnut Bord 250 Wlnut Reserh Reports 2009

11 REFERENCES 1. Adskveg, J. E, et l Annul Wlnut Reserh Reports Wlnut Mrketing Bord. Srmento, CA. 2. Conover, R. A. nd Grenhold, N. R Mixtures of opper nd mne or mnoze for ontrol of teril spot of tomto (Xnthomons mpestris pv. vesitori) nd their omptiility for ontrol of fungus diseses. Pro. of Fl. Stte Horti. So. 94: Lee, Y. -A., M. N. Shroth, M. Hendson, S. E. Lindow, X. -L. Wng, B. Olson, R. P. Buhner, nd B. Teviotdle Phytopthology 83: Miller, P. W. nd W. B. Bollen Oregon Agri. Exp. Stn. Teh. Bull pp. 5. Mulren, E. N. nd M. N. Shroth Phytopthology 71: Mulren, E. N. nd M. N. Shroth Phytopthology 72: Ogw, J. M. nd H. English Diseses of Temperte Zone Tree Fruit nd Nut Crops. University of Cliforni, Division of Agriulture nd Nturl Resoures, Oklnd, CA. Pul. No pp. 8. Teviotdle, B. L., M. N. Shroth, nd E. N. Mulren In: Wlnut Orhrd Mngement. Ed. y D. E. Rmos. Univ. of Clif. Coop. Ext. Pul Cliforni Wlnut Bord 251 Wlnut Reserh Reports 2009

12 Fig. 1. Effiy of seleted opper tretments on v. Vin wlnut under nturl rinfll onditions - Solno Co Control Applitions were done on 4-1, 4-23, nd Koide l + Mnzte 75DF l Disese ws evluted in Koide l + Mnzte 75DF 1.3 l erly June. Inidene of disese is sed on Koide l + Mnzte F45 32 fl oz fruit for eh 5 single-tree Koide l + Mnzte 75DF 2.4 l replitions. Bdge X2 IRF070 4 l + Mnzte 75DF 2.4 l Koide 3000 = 30% me Bdge X2 IRF070 4 l + Mnzte F45 58 fl oz Koide 2000 = 35% me Bdge X2 = 28% me Disese inidene (%) Fig. 2. Effiy of new teriide tretments on v. Hrtley wlnut under nturl rinfll onditions - Solno Co Control Ksumin 2L 100 ppm Ksumin 100 ppm + Mnzte DF 2.4 l Ksumin 100 ppm + Koide l Mnzte DF 2.4 l 8 l Mnkoide 8 l Mnkoide 4 l Koide l + Mnzte DF 2.4 l Koide l + Mnzte DF 2.4 l+ BioForge 1 pt/0.5 pt* Koide l + Mnzte DF 2.4 l Bdge X2 (28%me) 4 l + Mnzte DF 2.4 l Kentn DF (40% me) 5.25 l + Mnzte DF 2.4 l Disese inidene (%) Applitions were mde on 4-6, 4-23, 4-30, nd Bioforge ws used t 1 pt t the first pplition nd t 0.5 pt t the following pplitions.disese ws evluted in erly June. Inidene of disese is sed on fruit of eh of four single-tree replitions. Fig. 3. Effiy of seleted opper tretments on v. Vin wlnut under nturl rinfll onditions - Yu-Sutter Co Control Cereroide 0.5% Atinovte 12 oz + Brekthru 2 fl oz Regli 1% d Ksumin 2L 100 ppm + NuFilm P 8 fl oz Koide l Mnzte F45 58 fl oz Ksumin 100 ppm + NuFilm-P 8 fl oz + Koide l de Ksumin 100 ppm + NuFilm-P 8 fl oz + Mnzte F45 58 fl oz Ksumin 100 ppm+nufilm-p 8 fl oz+mnzte 58 fl oz+rezist 1 pt+regli 1% d Koide l + ReZist 1 pt de Koide l + Mnzte F45 58 fl oz de Koide l + Mnzte F45 58 fl oz + ReZist 1 pt de Kentn 40DF 5.25 l + Mnzte F45 58 fl oz e Bdge SC 4 l + Mnzte F45 58 fl oz de Disese inidene (%) Applitions were done on 4-1 (tkin), 4-7 (pistillte), 4-16, 4-21, 5-1, nd Disese ws evluted on Inidene of disese is sed on fruit for eh 5 single-tree replitions. Cliforni Wlnut Bord 252 Wlnut Reserh Reports 2009

13 Fig. 4. Effiy of new teriide tretments on v. Hrtley wlnut under nturl rinfll onditions - Solno Co Control Ksumin 2L 100 ppm Mnzte F45 58 fl oz Mnkoide 8 l Mnkoide 4 l Koide l Ksumin 100 ppm + Mnzte F45 58 fl oz Ksumin 100 ppm + Koide l Ksumin 100 ppm + Mnzte F45 58 fl oz + BioForge 0.5 pt Koide l + Mnzte F45 58 fl oz Disese inidene (%) Applitions were mde on 4-6, 4-23, 4-30, nd Disese ws evluted in erly June. Inidene of disese is sed on fruit for eh 5 single-tree replitions. Fig. 5. Effiy of new teriide tretments on v. Chio wlnut with simulted rin pplied - Fresno Co Control Cereroide 1% Atinovte 12 oz + Brekthru 2 fl oz Ksumin 2L 100 ppm d d d Mnzte DF 2.4 l d Koide l Ksumin 100 ppm + Mnzte DF 2.4 l Ksumin 100 ppm + Koide l d Ksumin 100 ppm + Mnzte DF 2.4 l + BioForge 1 pt/0.5 d pt* Koide l + Mnzte DF 2.4 l d Koide l + ReZist 1 pt d Koide l + Mnzte DF 2.4 l + ReZist 1 pt Disese inidene (%) Applitions were mde on 4-2, 4-16, 4-22, 5-1, nd Bioforge ws used t 1 pt t the first pplition nd t 0.5 pt t the following pplitions. Simulted rin ws pplied for 6-8 h on , 4-18, , , nd Disese ws evluted on Inidene is sed on the numer of disesed nuts of the totl of nuts evluted of eh of four single-tree replitions. Fig. 6. Effiy of new teriide tretments on v. Chndler wlnut with simulted rin pplied - Fresno Co Control Regli SC 0.25% Cereroide 0.5% Atinovte 12 oz + Brekthru 2 fl oz BioForge 1 pt/0.5 pt* Ksumin 100 ppm + Mnzte DF 2.4 l + BioForge 1 pt/0.5 pt* Koide l + Mnzte DF 2.4 l + BioForge 1 pt/0.5 pt* Disese inidene (%) Applitions were mde on 4-6, 4-15, 4-22, nd Bioforge ws used t 1 pt t the first pplition nd t 0.5 pt t the following pplitions. Simulted rin ws pplied for 6-8 h on 4-8, 4-18, 4-24, 5-2, nd Disese ws evluted on nd is sed on the numer of disesed of totl of nuts evluted of eh of four single-tree replitions. Cliforni Wlnut Bord 253 Wlnut Reserh Reports 2009

14 Fig. 7. Effiy of new hemil nd iologil tretments on v. Tulre wlnut under nturl rinfll onditions - Solno Co Control Atinovte 12 oz + Brekthru 2 fl oz Cereroide 0.5% Regli 1% MOI 106B 1% BioForge 1 pt/0.5 pt* ReZist 1 pt Koide l + Mnzte 75DF 2.4 l Kentn DF 5.25 l + ReZist 1 pt Disese inidene (%) Applitions were done on 4-2, 4-23, nd Bioforge ws used t 1 pt t the first pplition nd t 0.5 pt t the following pplitions. Disese ws evluted in erly June. Inidene of disese is sed on fruit evluted for eh 5 single-tree replitions. (C)/Preipittion (mm) Temperture Mr Fig. 8. Timing study with Koide-Mnzte tretments in v. Vin orhrd under simulted rin onditions - Fresno Co Preip (mm) Mx Air Temp ( C) Min Air Temp ( C) Dew Period 8-Mr Pistillte Flowering Strts 15-Mr Bteriide pplitions 22-Mr 29-Mr 5-Apr 12-Apr Simulted rin pplitions 19-Apr Dte 26-Apr 3-My 10-My 17-My 24-My 31-My 7-Jun 14-Jun No. Tretment Pist. emergene 3-31 Burst simul. rin* 4-2, 4-6 X'st 4-10 Burst simul. rin 4-11, 4-14 X'st 4-29 Burst simul. rin 5-8, Control --- X --- X --- X 2 Koide Mnzte X --- X --- X 3 Koide Mnzte X --- X 4 Koide Mnzte X 5 Koide Mnzte DF --- X 6 Bdge X2 + Mnzte X --- X 7 Bdge X2 + Mnzte X Disese inidene (%) Koide 3000 nd Bdge X2 were pplied t rte of 4 l nd Mnzte t rte of 2.4 l/100/a. Burst simulted rin: Two 6-8 h rin events 3-4 dys prt. Nturl rin ourred on (4.5 mm). Totl preipittion etween 4-1 nd ws 6.6 mm. Disese ws evluted on Cliforni Wlnut Bord 254 Wlnut Reserh Reports 2009

15 Fig. 9. Timing study with Koide-Mnzte tretments in v. Chio orhrd under nturl rinfll onditions - Solno Co A. )/Preip. (mm) Preip (mm) Min Air Temp ( C) Mx Air Temp ( C) Dew Period Temp. (C 10 0 B t Index X Cst C X C Cst Index Bteriide pplitions - Chio Chio 7-dy XnthoCst indies with spry progrm 4 Chio Pistillte Flowering Strts 7-dy XnthoCst indies without spry progrm Progrm No. 1-Mr 8-Mr 15-Mr 22-Mr 29-Mr 5-Apr 12-Apr 19-Apr Dte 26-Apr 3-My 10-My 17-My 24-My 31-My 7-Jun 14-Jun XntoCst indies were otined from the AgTelemetry wether sttion in Winters, CA. D. Effiy of progrms on v. Chio No. Trt Erly pistillte loom Pistillte full loom X'Cst X'Cst X'Cst 1 Control Koide Mnzte DF Koide Mnzte DF Koide Mnzte DF Koide Mnzte DF Disese inidene (%) Koide 300 ws pplied t rte of 4 lv nd Mnzte t rte of 2.4 l in volume of 100 gl/a. Nturl rinfll ourred on 4/7/09 to 4/10/09 (14.2 mm), 5/1/09 to 5/9/09 (3.8 mm), nd 6/2/09 to 6/5/09 (6.8 mm). Totl preipittion from 4/1/09 to 6/10/09 ws 34.5 mm. Disese ws evluted in erly June. Cliforni Wlnut Bord 255 Wlnut Reserh Reports 2009

16 Fig. 10. Environmentl onditions, XnthoCst 7-dy indies, nd disese progress in ommeril v. Vin orhrd under nturl rinfll onditions - Sutter Co A. /Preip. (mm) Temp. (C)/ B. X Cst Index Preip (mm) Mx Air Temp ( C) Min Air Temp ( C) Dew Period Bteriide pplitions X'Cst 7-dy X'Cst Sesonl Dis. inidene in est tretment XnthoCst indies with spry progrm Pistillte Flowering Strts C. X Cst Index X'Cst 7-dy X'Cst Sesonl Disese Progress Mr XnthoCst indies without spry progrm 1-Apr 8-Apr 15-Apr 22-Apr 29-Apr 6-My 13-My Dte XntoCst indies were otined from the AgTelemetry wether sttion in Rio Oso, CA. 20-My 27-My Cliforni Wlnut Bord 256 Wlnut Reserh Reports 2009

17 Fig. 11. Wlnut vriety suseptiility to light in simulted rin-treted orhrd - Fresno Co PI e efg Frnquette Cheinovo de de de g efg defg Sinensis 5 de defg PI18256 Chse D9 Hrtley Serr Chndler Adms Tulre Pyne de de de de d d g def de defg de d g defg efg defg def ef d ef 2007 de ef defg def 2008 d d Disese inidene (%) Five to six weekly simulted rin events were pplied using high-ngle sprinkler system etween April nd My. d d d d d d 2009 Cliforni Wlnut Bord 257 Wlnut Reserh Reports 2009