PRELIMINARY FINAL REPORT WFTRC Project #AH-1-83 WSU Project #13C-3619-6748 Title: PI: Orgniztion: Co-PIs nd ffilitions: Improving Clcium nd Zinc Spry Progrms for Wshington Apple Orchrds Frnk J. Perye, Soil Scientist WSU Tree Fruit Reserch nd Extension Center, Wentchee, WA Clcium Dr. Gerry Neilsen, Pcific Agri-Food Reserch Centre, Agriculture Agri- Food Cnd, Summerlnd, BC Dr. Dn Fuion, WSU Coopertive Extension, Ykim, WA Lenticel rekdown Dr. Eric Curry, USDA-ARS, Wentchee Coopertors: Alln Bros., Nches, WA; Borton & Sons, Tieton, WA Ojective: The ojective of this reserch ws to improve the effectiveness of clcium (C) nd zinc (Zn) spry progrms in Wshington orchrds therefore influencing plnt tissue C nd Zn sttus, fruit firmness, nd incidences of itter pit nd lenticel rekdown. Clcium nd Zn deficiencies re very common in the Wshington tree fruit industry. Low fruit C is strongly ssocited with incresed likelihood of itter pit development nd possily lenticel rekdown in pples. Clcium sprys hve een conclusively shown to reduce the likelihood of itter pit development, while recent reserch in Brzil concluded tht C chloride sprys cn reduce the incidence of lenticel rekdown in Gl pple. While pple fruit firmness is positively relted to fruit C concentrtion, the ility of C sprys to increse fruit C y n mount tht cn detectly improve fruit firmness is inconsistent. Low tree Zn sttus is ssocited with little lef, rosetting, lef chlorosis, lind wood nd shoot dieck. These deficiencies re treted with folir sprys of Zn. Mngement of Zn nutrition in Wshington orchrds is prticulrly prolemtic ecuse ppliction of the element is regulted y the Wshington Deprtment of Agriculture, which seeks to minimize its relese into the environment. Significnt findings (sed on 21-2 nd some 23 ctivities): NOTE: Reserch ctivities re ongoing t the time of report preprtion; hence, these findings re suject to chnge sed on impending 23 results nd will e updted for the Reserch Commission meetings in Jnury 24. Boron pplied tnk-mixed with Zn plus oil t delyed dormnt timing is s effective s oron pplied t pink timing in pple, per nd sweet cherry [work supported y U.S. Borx nd WSU]. Spry ppliction of high rtes of Zn sulfte during the dormnt period ( trditionl recommendtion) ws the only Zn tretment tht sustntilly improved winter ud Zn sttus of pple trees, which my ccount for the longstnding success of this trditionl spry. It justifies keeping the current Wshington Deprtment of Agriculture exemption llowing higher hevy metl (in this cse, Zn) ppliction rtes when the hevy metl is required for plnt nutritionl purposes.
The Zn in the Zn phosphte-sed NutrPhos 24 nd NutrPhos ZnK is very poorly ville. Oxide, sic Zn sulfte, chelted nd orgniclly sed Zn products contin more-or-less eqully phytoville Zn, with smll differences etween products. The min distinguishing chrcteristic likely will e price per unit phytoville Zn. Clcium chloride sprys sustntilly reduced itter pit in HoneyCrisp nd Breurn pple where the incidence of itter pit ws high. Strting sprys in June ws more effective thn strting sprys in July. Strting sprys in My ws no more effective thn strting in June. Clcium sprys hd sustntil effect on itter pit in Fuji pple in 21 when the ckground incidence of itter pit ws high ut not in 22 when the ckground itter pit incidence ws low. Boom-spry pplictions of high rtes of C thiosulfte to soil filed to increse fruit C concentrtion or to reduce itter pit incidence in pple. Contrry to Polish report, pplying very high rtes of C s C chloride or MirCl one week efore hrvest filed to improve pple fruit firmness. Clcium in C chloride is more phytoville thn C in MirCl, t equivlent totl C rtes. TechSpry Copper (Nutrient Technologies) t the 2-qurt/cre rte pplied t first cover sustntilly improved internl lef Cu concentrtions of Golden Delicious pple trees compred to the previous yer (from 4. to 14 mg/kg). Methods, results nd discussion (21-23): The complete experimentl results for 23 re not ville t the time of report preprtion ecuse smple collection, processing, nlysis nd interprettion re ongoing. Most of dt should e ville in time for the Reserch Commission review meeting in Jnury 24. Study 1. Evlute the effect of C nd potssium sprys on the incidence of lenticel rekdown on Fuji nd Gl pples. In response to request y industry personnel, I estlished collortion in 23 with Dr. Eric Curry, USDA-ARS, Wentchee. Field trils were conducted in which multiple C nd potssium sprys were pplied to Fuji nd Gl pples in n ttempt to influence the incidence of lenticel rekdown. My progrm contriuted technicl field support for the experiments. The results of this study will e provided in the report y Dr. Curry t the Posthrvest Review of the Reserch Commission. Study 2. Compre the effect on itter pit of MirCl sprys pplied t low-frequency high-rte with C chloride sprys pplied t high-frequency low-rte. MirCl is elieved to e less phytotoxic ut is more expensive thn folir-grde C chloride. The ojective of this experiment is to determine if using fewer pplictions t higher C rtes cn reduce the net cost of MirCl sprys. The min cost sving comes from reducing the numer of sprys required during the seson. Four sprys of MirCl t 12 l C/cre/spry were compred to eight sprys of C chloride t 6 l/cre/spry on Fuji pples t WSU Smith Trct. Results in 21 indicted tht C chloride provided superior itter pit control over MirCl. There ws no tretment difference in either itter pit incidence or fruit C concentrtion in 22, proly due to the very low incidence of itter pit in tht yer (Fig. 1). Differentil C spry tretments were pplied in 24, fruit smples were collected t commercil hrvest nd re eing ssessed for mss, itter pit incidence nd fruit C content.
Fig. 1. Fuji pple, Smith Trct, Orondo, 22 8 iweekly sprys of C chloride t 2 l C/c/spry; 4 monthly sprys of MirCl t 4 l C/cre/spry Clcium Rte (l C/cre/spry) 6 4 3 2 1 C spry schedule C chloride MirCl /1/2 6/1/2 7/1/2 8/1/2 9/1/2 Bitter Pit (% of field-run fruits) 8 6 4 2 Bitter Pit Control C chloride MirCl Fruit C (corticl plugs, ppm dm) 2 1 1 Fruit C Control C chloride MirCl Clcium Tretment Study 3. Determine est strt timing for C sprys for itter pit control. There is elief tht strting C spry ppliction during the cell division stge of fruitlet development my enhnce itter pit control. A study ws conducted strting in 22 on Breurn pple t Alln Bros., Nches, nd on HoneyCrisp pple t Borton & Sons, Tieton, evluting the effect on itter pit nd fruit C of six iweekly sprys of C chloride t 6 l/cre/spry strting in My, June or July. The C sprys hd no effect on fruit mss or firmness nd sustntilly reduced itter pit incidence (Figs. 2 nd 3). The sprys strted in My nd June were more effective t controlling itter pit thn the July-strt spry on the HoneyCrisp, ut there were no tretment differences on the Breurns. Fruit C concentrtion tended to e higher in the lter strt spry tretments. The experimentl tretments were repeted in 23. Fruit smples were collected t commercil hrvest nd re eing ssessed for mss, itter pit incidence, firmness nd fruit C content. Fig. 2. Alln Bros., Nches, 22 3 weekly soil sprys of ThioCl strting My 8 (4 gl/spryed cre/spry); 6 sprys of 6 l CCl 2 /cre/spry strting in mid-my, mid-june, or mid-july Fruit Mss (g) 2 2 1 1 Fruit mss Bitter Pit (% of field-run fruits) 8 6 4 2 Bitter Pit Control ThioCl My June July Control ThioCl My June July Fruit Firmness (l-force) 2 1 1 Fruit firmness Fruit C (corticl plugs, ppm dm) 17 1 12 1 7 2 Fruit C c Control ThioCl My June July Control ThioCl My June July Clcium Tretment Clcium Tretment
Fig. 3. HoneyCrisp pple, Borton & Sons, Tieton, 22 3 weekly soil sprys of ThioCl strting My 8 (4 gl/spryed cre/spry); 6 sprys of 6 l CCl 2 /cre/spry strting in mid-my, mid-june, or mid-july Fruit Mss (g) 4 3 3 2 2 1 1 Fruit mss Bitter Pit (% of field-run fruits) 4 3 2 1 c d Bitter Pit Control ThioCl My June July Control ThioCl My June July Fruit Firmness (l-force) 2 1 1 Fruit firmness Control ThioCl My June July Fruit C (corticl plugs, ppm dm) 12 1 7 2 Fruit C c c Control ThioCl My June July Clcium Tretment Clcium Tretment Study 4. Effectiveness of soil-pplied ThioCl (clcium thiosulfte) on itter pit. Fuji pple, WSU Smith Trct; Breurn pple, Alln Bros., Nches; nd HoneyCrisp pple, Borton & Sons, Tieton. Soil ppliction of ThioCl t high rtes (12 gl/spryed cre) hs een reported to enhnce tree C sttus nd improve fruit qulity. We evluted three weekly soil-pplied sprys of Thiocl t 4 gl/spryed cre/spry (totl 12 gl/spryed cre) t two loctions nd single spry of 12 gl/cre t one loction. The soil pplictions of ThioCl filed to influence fruit C concentrtion or firmness (Figs. 2 nd 3). It incresed itter pit incidence in one of the test sites, which my e sttisticl nomly. The experimentl tretments were repeted in 23. Fruit smples were collected t hrvest nd re undergoing nlysis. Study. Effect of immedite prehrvest sprys of very high rtes of C on fruit firmness. A Polish report in fll 21 climed tht very high rtes of C chloride pplied one week efore hrvest consistently enhnced firmness retention y out 2% in Jongold pples stored in refrigerted ir for 12 dys. I conducted study in 22 exmining the effect of C chloride or MirCl ppliction t 2 l C/cre 7 to 9 dys efore hrvest on firmness nd C content of Gl, Golden Delicious, Breurn nd Fuji pples. The high C sprys filed to improve fruit firmness t hrvest or fter 3 dys storge in refrigerted ir (Fig. 4). The pples treted with C chloride hd redily oservle film of moisture on their surfces, consistent with its high hygroscopicity nd ility to pull nd retin moisture out of the ir. The C chloride cused no injury on the fruit. The MirCl dried s powdery white coting. It cused no injury on the Breurn, Golden Delicious nd Gl pples ut cused lenticel urning on every one of the MirCl-spryed Fuji pples. Considerly more C ws tken up y the fruit treted with C chloride thn with MirCl (Fig. ). It ppers tht the pulished enefit of the high C tretment on pple firmness my e cultivrdependent or expressed only when fruit is unusully stressed, such s y long-term refrigerted ir storge s ws done in the Polish study (12 dys). This study ws not repeted in 23 ecuse of filure to find ny eneficil effect on fruit firmness.
Fig. 4. Effect of very high C spry (2 l C/1 gl) pplied one week efore hrvest on firmness of pples t-hrvest or stored 3 dys in refrigerted ir, 22. (Cont=control; Mir=MirCl; C=CCl2; =t-hrvest, 3=3 dys storge) 2 Breurn 2 Fuji Firmness (l-force) 2 1 1 Firmness (l-force) 1 1 Cont- Mir- C- Cont-3Mir-3 C-3 Cont- Mir- C- Cont-3Mir-3 C-3 18 16 Golden Delicious 18 16 Gl Firmess (l-force) 14 12 1 8 6 4 Firmness (l-force) 14 12 1 8 6 4 2 2 Cont- Mir- C- Cont-3Mir-3 C-3 Cont- Mir- C- Cont-3Mir-3 C-3 Clcium Tretment Clcium Tretment Fruit C (corticl plugs, ppm dm) Fruit C (corticl plugs, ppm dm) 2 2 1 1 Fig.. Effect of very high C spry (2 l C/1 gl) pplied one week efore hrvest on fruit clcium of pples t-hrvest or stored 3 dys in refrigerted ir, 22. (Cont=control; Mir=MirCl; C=CCl2; =t-hrvest, 3=3 dys storge) 4 4 3 3 2 2 1 1 Breurn Cont- Mir- C- Cont-3Mir-3 C-3 Golden Delicious Cont- Mir- C- Cont-3Mir-3 C-3 Clcium Tretment Fruit C (corticl plugs, ppm dm) Fruit C (corticl plugs, ppm dm) 3 3 2 2 1 1 4 4 3 3 2 2 1 1 Fuji Cont- Mir- C- Cont-3Mir-3 C-3 c Gl Cont- Mir- C- Cont-3Mir-3 C-3 Clcium Tretment c Study 6. Evlution of 12 Zn spry products for postloom use. Fourth yer of field tril exmining the effectiveness of multiple postloom pplictions of 12 Zn spry products. The Zn products re Biomin Zinc (JH Biotech), CM Liquid 9% Zinc (Custom Ag Formultions), Keylte Zinc (Stoller), Nutr-phos -24- (Pce Interntionl), Nutr-phos Zn-K (Pce Interntionl), Nutr-spry Zinc (Pce Interntionl), Tech-flo Zet Zinc 22 (Nutrient Technologies), Zinc Metloste (Alion Lortories), Zinc X-tr (Custom Ag Formultions), ZincMx (Plskem), Zinc polymine (Phyto Chem), nd regent-grde Zn nitrte. During the 2-22 sesons, the Zn sprys were pplied twice postloom to ering Golden Delicious pple trees t rte equivlent to. or 1. l ctul Zn per cre per spry. Zinc nitrte hd the gretest effect on lef Zn concentrtion ut ws likely to cuse fruit mrking. Zinc in the orgniclly-complexed/chelted forms of Zn ws
intermedite in phytovilility, nd the inorgnic compounds contined the lest phytoville Zn. (Fig. 6). The verge Jnury 23 ud concentrtions of the trees receiving Zn sprys were solutely higher thn the control (Fig. 7); however, the differences were not sttisticlly significnt. The ud dt do suggest tht long-term ppliction of Zn t low rtes my hve eneficil effect on tree Zn sttus, prticulrly in the spring when Zn deficiency is most likely to occur. All of the compounds cn provide sufficient Zn to generte lef Zn concentrtions tht re considered desirle if pplied t high enough rtes; however, the costs of the products re widely divergent nd need to e considered, s does the desirility of the gol of minimizing Zn relese in the environment. No Zn sprys were pplied in 23, ut lef smples were collected in summer 23 nd re eing nlyzed for minerl element sttus to determine the residul effects, if ny, of the previous three yers of sprys. Bud smples will e collected in Jnury 24. Fig. 6. Effect of postloom Zn sprys on Lef Zn Sttus 'Golden Delicious'/M.9 Apple, 2-2 2 Postloom Sprys of. (2) or 1. (21-2) l Zn/cre/spry Zn Nitrte CM 9% Zn Zn Metloste Zn X-tr Biomin Zn ZincMx Zn Polymine Keylte 9% Zn Zet Zn 22 NutrSpry Zn Nutrphos Zn-K Nutrphos 24 wter orgnic complex orgnic complex orgnic complex orgnic complex orgnic complex orgnic complex orgnic complex oxysulfte oxide phosphte phosphte nitrte Only product tht cused fruit mrking 2 4 6 8 1 12 Reltive Effect of Zn Spry products on Internl lef Zn, verged over 3 yers (NutrPhos 24 = 1.) Fig. 7. Effect of postloom Zn sprys on Bud Zn Sttus 'Golden Delicious'/M.9 Apple, 2-2 2 Postloom Sprys of. (2) or 1. (21-2) l Zn/cre/spry Zn Nitrte CM 9% Zn Zn Metloste Zn X-tr Biomin Zn ZincMx Zn Polymine Keylte 9% Zn Zet Zn 22 NutrSpry Zn Nutrphos Zn-K Nutrphos 24 wter 2 4 6 8 Jnury 23 Bud Zinc Concentrtion (mg/kg) fter 3 yers of postloom Zinc spry pplictions
Study 7. Comprison of Zn ppliction prctices. Third yer of field tril compring the performnce of trditionl Zn spry tretments with promising postloom Zn spry products. Tretments were s follows: Unspryed control. Folir-grde ZnSO 4 (3.% Zn) pplied during the lte dormnt period (just efore ny green tissue shows on the uds) t rte equivlent to 7.329 l ctul Zn per cre [Wshington Deprtment of Agriculture mximum rte for Zn contminnt in fertilizer]. Folir-grde ZnSO 4 (3.% Zn) pplied during the lte dormnt period t rte equivlent to 3.664 l ctul Zn per cre. Folir-grde ZnO (% Zn) plus 1% horticulturl oil pplied t the delyed-dormnt stge (greentip to hlf-inch green) t rte equivlent to 2. l ctul Zn per cre. ZincMx pplied one week fter green-tip, two weeks fter petl fll, nd four weeks fter petl fll t rte equivlent to.1 l ctul Zn per cre per spry. Alion Metloste Zinc pplied one week fter green-tip, two weeks fter petl fll, nd four weeks fter petl fll t rte equivlent to.1 l ctul Zn per cre per spry. Lortory studies of Zn soluility in Zn spry solutions, coupled with X-ry diffrction studies, reveled tht the current Leffingwell NutrSpry Zinc is formulted entirely with zinc oxide nd is not the sme product s the clssic Leffingwell NutrSpry Zinc. The chnge in formultion ccounts for the sustntil increse in lel rte for the new product. Lef smples of 21-3 were nlyzed two wys in order to determine the internl Zn concentrtion s well s the mount of residues on lef surfces (Fig. 8). Internl lef Zn concentrtions were identicl in the control, the two zinc sulftes, nd NutrSpry Zinc-treted trees. Both ZincMx nd Alion Metloste Zinc sustntilly incresed totl nd internl lef Zn, with ZincMx hving greter effect. The sustntil increse in Jnury ud Zn oserved in 22 for the high Zn sulfte tretment filed to pper in 23. Lef smples collected in summer 23 re eing nlyzed for minerl element sttus. Dmge to fruit finish lso ws ssessed. Bud smples will e collected in Jnury 24.
Fig. 8. Prtitioning of totl zinc in leves nd uds, 21-3 Comprison of vrious zinc spry prctices (W18W, Golden Delicious) 4 X ZincMx.4 l Zn/cre 4 X Zinc metloste.4 l Zn/cre 1 X delyed dormnt NutrSpry Zinc 1 X lte dormnt high Zinc sulfte 1 X lte dormnt low Zinc sulfte Unspryed control 2 l Zn/cre 7.33 l Zn/cre 3.66 l Zn/cre none Internl Zinc Externl Zinc Minimum desired Bud Zn 1 2 3 4 2 4 6 8 Lef Zinc, August 21 (ppm) Bud Zinc, Jn 22 (ppm) 3 X ZincMx 3 X Zinc metloste 1. l Zn/cre.84 l Zn/cre 1 X delyed dormnt NutrSpry Zinc 3.66 l Zn/cre 1 X lte dormnt high Zinc sulfte 7.33 l Zn/cre 1 X lte dormnt low Zinc sulfte Unspryed control 3.66 l Zn/cre none Internl Zinc Externl Zinc Minimum desired Bud Zn 1 2 3 4 6 7 8 9 1 11 2 4 6 8 Lef Zinc, August 22 (ppm) Bud Zinc, Jn 23 (ppm) Other support of project: C nd Zn fertilizer mterils were provided y interested fertilizer mnufcturers nd distriutors. Field experimentl sites were provided y Borton nd Sons, Ykim, nd Alln Bros., Ykim, nd y WSU. Fcilities, nlyticl instrumenttion, PI funding, nd the mjority of technicl support funding were provided y WSU College of Agriculture nd Home Economics. Budget: Project title: PI: Project durtion: 21-23 Project totl (3 yers): $139,28 Improving Clcium nd Zinc Spry Progrms for Wshington Apple Orchrds Frnk J. Perye Yer Yer 1 (21) Yer 2 (22) Yer 3 (23) Totl 48,16 49,9 41,22