Peach and Plum. Wednesday morning 9:00 am

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1 Peach and Plum Wednesday morning 9:00 am Where: Grand Gallery (main level) Room C MI Recertification credits: 2 (1C, COMM CORE, PRIV CORE) OH Recertification credits: 1 (presentations as marked) CCA Credits: PM(2.0) Moderator: Will Bristol, MSHS Board, Romeo, MI 9:00 am From Fungicide Resistance Fears to Contentment: Brown Rot Management in NY Kerik Cox, Plant Pathology and Plant-Microbe Biology, Cornell Univ. 9:30 am Managing Peach Insects Where Oriental Fruit Moth Is Resistant to Pyrethroid Insecticides (OH: 2B, 0.5 hr) Rick Weinzierl, Entomology Dept., Univ. of Illinois 10:00 am Current Studies on Epidemiology and Management of Bacterial Spot of Stone Fruit (OH: 2B, 0.5 hr) Sarah Bardsley Capasso, Plant Pathology and Environmental Microbiology, Penn State Univ. 10:40 am Focus on Selected New Peach Varieties Bill Shane, Extension Fruit Specialist, MSU Extension, Benton Harbor, MI 10:55 am Session Ends

2 Managing Peach Insects Where Oriental Fruit Moth is Resistant to Pyrethroid Insecticides Rick Weinzierl, University of Illinois Beginning in 2004, oriental fruit moth (OFM) infestations in fruit occurred at unexpected levels in peach orchards treated with pyrethroid insecticides in Calhoun County in southwestern Illinois. Laboratory and field research later found that these failures resulted from pyrethroid resistance in local populations. As a result, orchardists in the affected area have switched to mating disruption or a combination of organophosphate and reduced-risk insecticides for OFM control. Pyrethroids remain in use as well, however, along with certain neonicotinoids, because of their value for control of stink bugs (and plant bugs, Japanese beetles, and a few other sporadic pests). This summary reviews the history of research on OFM resistance to pyrethroids in Illinois and describes current recommendations for peach insect management where the best approaches to OFM control must be merged with separate practices for control of brown marmorated stink bug (BMSB), other stink bugs, and additional pest species. Documentation of Resistance Kanga et al. (1997 and 2003) described OFM resistance to pyrethroid insecticides in Ontario before it became a problem in Calhoun County, IL. Repeated use of pyrethroid insecticides for peach insect management was common in southern and southwestern Illinois peach orchards in the early 2000s. Several registered pyrethroids offered good to excellent control of plum curculio, OFM, Japanese beetle, stinks bugs, and plant bugs, and the increasing availability of generic products made the use of pyrethroids relatively inexpensive. Initial reports of OFM-infested fruits in pyrethroid-treated orchards in 2004 occurred during a year when repeated heavy rainfalls washed residues from plants and made timely applications and reapplications difficult. So although initial control failures raised suspicions about resistance, absence of consistent residues on fruits was definitely a problem. By 2006, although we had done no bioassays to confirm resistance, we had recommended to shift away from pyrethroids to Imidan, Guthion, SpinTor, Intrepid, or mating disruption for OFM control. (Current reduced-risk insecticides were not yet labeled in 2006.) In 2007 an early April freeze destroyed over 95 percent of the peach and apple crop in Calhoun County. We were able to collect larvae from new shoots in untreated peach orchards throughout the 2007 season and establish a laboratory colony for insecticide bioassays that continued through We also started a second colony using OFM pupae from an insecticide-susceptible colony maintained for over 40 years at Rutgers University in New Jersey. We used these colonies in bioassays to establish baseline estimates of the toxicity of chlorantraniliprole (Altacor), spinetoram (Delegate), spinosad (Spintor), acetamiprid (Assail), esfenvalerate (Asana), and lambda-cyhalothrin (Warrior) to susceptible OFM and to provide a comparison to document resistance to pyrethroids (specifically esfenvalerate) in populations from Calhoun County orchards (see Jones et al. 2010, 2011a, 2011b, 2012). By 2010, we had developed and used a diagnostic dose of esfenvalerate on field-collected adult males from two commercial orchards in Calhoun County and one untreated orchard at Urbana, IL, and on adult males from our laboratory colonies. Results indicated 9 percent and 82 percent occurrence of resistant males in two Calhoun County orchards. Since 2010 (and earlier), most Calhoun county peach growers rely primarily on mating disruption (mostly Isomate-M Rosso or Isomate-OFM Twin Tubes) for OFM

3 control. Mating disruption has not been effective in orchards with separate small blocks of apples and peaches in close proximity to each other if pheromone dispensers are placed only in peaches. In these orchards with adjacent small blocks of apples and peaches, Imidan, Assail, Altacor, Delegate, and Rimon are used in various sequences for OFM control. Current Management Recommendations The insecticides used for OFM (including mating disruption products) are not very effective, if at all effective, against BMSB, other stink bugs, or plant bugs. Imidan, Assail, Altacor, Delegate, and Rimon vary in their effectiveness against other pests (see Table 1). Although recommendations vary according to locations, histories, and monitoring results in individual orchards, our (IL) condensed recommendations for peach insect management in the presence of pyrethroid-resistant OFM are Delayed dormant: Use superior oil for San Jose scale and European red mite control according to orchard history. At pink, (1) if a pre-bloom spray for stink bugs or plan bugs is warranted based on site history or sampling, use a pyrethroid from Table 1; (2) where mating disruption is to be used for OFM control, apply dispensers per label rate; (3) hang pheromone traps baited with OFM L2 lures to monitor OFM flight. At petal fall, (1) Apply mating disruption dispensers (LPTB Dual) for control of both peachtree borer species or hang pheromone traps baited with LPTB lures to monitor lesser peachtree borer flight and additional traps baited with peachtree borer (GPTB)lures to monitor peachtree borer flight; (2) use Assail, Calypso, Imidan, or a pyrethroid for plum curculio control if stink bug control is necessary, choose a pyrethroid to serve the dual purpose or use Belay for combined control of stink bugs, plant bugs, and plum curculio. Where mating disruption is not used to control LPTB and peachtree borer and traps indicate a significant flight, use trunk sprays of Lorsban (once per year) or a pyrethroid such as Asana, Baythroid, Pounce, or Warrior. For LPTB, apply 7 to 10 days after traps begin to catch moths; for peachtree borer, apply at peak moth flight or immediately after harvest. Cover sprays: (1) time OFM sprays according to counts from pheromone traps if mating disruption is not used; most effective insecticides against pyrethroid-resistant populations are Imidan, Assail, Rimon, Altacor, and Delegate; (2) for Japanese beetle control, see Table 1 to choose an insecticide that also controls OFM and stink bugs; (3) for stink bug control, use a pyrethroid, Belay, or Lannate (BMSB). Controlling pyrethroid-resistant OFM during periods when stink bug or plant bug control is also needed will require some tank mixes or extra sprays. References Cited Jones, M.M., J.L. Robertson, and R.A. Weinzierl Susceptibility of oriental fruit moth (Lepidoptera: Tortricidae) to selected reduced-risk insecticides. Journal of Economic Entomology 103: Jones, M. M., J.L. Robertson, and R.A. Weinzierl. 2011a. Susceptibility of oriental fruit moth (Lepidoptera: Tortricidae) to two pyrethroids and a proposed diagnostic dose for field detection of resistance. Journal of Economic Entomology. 104: Jones, M. M., J.L. Robertson, and R.A. Weinzierl. 2011b. Susceptibility of eggs from two laboratory colonies of oriental fruit moth (Lepidoptera: Tortricidae) to novaluron. Journal of Agricultural and Urban Entomology 26:

4 Jones, M.M., J.L. Robertson, and R.A. Weinzierl Toxicity of thiamethoxam and mixtures of chlorantraniliprole plus acetamiprid, esfenvalerate, or thiamethoxam to neonates of oriental fruit moth (Lepidoptera: Tortricidae). J. Econ. Entomol. 105: Kanga, L., D. Pree, J. van Lier, and J. Whitty Mechanisms of resistance to organophosphorus and carbamate insecticides in Oriental fruit moth populations (Grapholita molesta Busck) Pestic. Biochem. Physiol. 59: Kanga L., D. Pree, J. van Lier, and G. Walker Management of insecticide resistance in oriental fruit moth (Grapholita molesta; Lepidoptera: Tortricidae) populations from Ontario. Pest Management Sci : Table 1. Efficacy of Selected Insecticides and Acaricides Against Peach Insects and Mites (from the 2016 Midwest Fruit Pest Management Guide). Product IRAC Code Predator Mite Toxicity Bee Toxicity Eur. Red Mite Plum Curculio Oriental Fruit Moth Peachtree Borers Japanese Beetle Plant Bugs / Stink Bugs San Jose Scale Spotted Wing Drosophila REI (hours) PHI (days) Organophosphates Diazinon 1B ST HT P G G G P F G Imidan 1B ST HT G E P G P P E Lorsban 1B MT HT E Carbamates Sevin 1A HT HT F F P E F P G 12 3 Lannate 1A HT HT F F F E E * 4 Neonicotinoids Actara 4A MT HT G E G Admire Pro 4A MT HT F F F Assail 4A ST MT E E F F F F 12 14* Belay 4A HT G E E G Calypso 4A MT MT E G P F F Insect Growth Regulators Centaur 16 ST ST E Esteem 7C ST ST F P E Intrepid 18 ST ST G F 4 7 Rimon 15 ST ST E 12 8

5 Product Pyrethroids IRAC Code Predator Mite Toxicity Bee Toxicity Eur. Red Mite Plum Curculio Oriental Fruit Moth Peachtree Borers Japanese Beetle Plant Bugs / Stink Bugs San Jose Scale Spotted Wing Drosophila Asana 3A HT HT G E 1 G E E E 12 14* Baythroid/ Renounce 3A HT HT G E 1 G E E E 12 7 Danitol 3A HT HT F G E 1 E E E 24 3 Mustang Maxx 3A HT HT E E 1 E E E Pounce 3A HT HT G E 1 G E G 12 14* Proaxis 3A HT HT G G 1 E E E Pyganic 3A ST ST P P F P 12 0 Warrior 3A HT HT G G 1 G E E E Other Altacor 28 ST ST P E 4 10 Apta 21A HT G F Avaunt 22 MT HT G F F G Belt 28 ST ST E F 12 7 Delegate 5 MT HT P E E 4 14 Entrust 5 ST MT P F G 4 14 Exirel 28 ST G E G G 12 3 Movento 23 MT G 24 7 Miticides Acramite un ST MT F 12 3 Agri-Mek 6 MT HT G Apollo 10A ST ST E Envidor 23 MT ST E 12 7 Nexter 21A HT MT G 12 7 Onager / Savey 10A ST ST E Portal 21A MT ST E 12 7 Zeal 10B MT ST E 12 7 REI (hours) PHI (days) 1 Pyrethroid-resistant populations of oriental fruit moth are not controlled by this insecticide. *Specific preharvest intervals or restricted entry intervals vary for different formulations, application rates, or geographical location. See product labels for details.

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7 1 Current Studies on Epidemiology and Management of Bacterial Spot of Stone Fruit Sarah Bardsley Capasso and Kari Peter Department of Plant Pathology and Environmental Microbiology Penn State University Fruit Research and Extension Center P.O. Box 330, Biglerville, PA Bacterial spot of stone fruit (caused by Xathomonas arboricola pv. pruni) is the most important bacterial disease of peach and nectarine in the eastern United States where symptoms regularly reduce yield on susceptible stone fruit cultivars. Symptoms of bacterial spot occur on leaves, twigs, and fruit. On leaves, angular, vein delimited lesions at the leaf tip, mid-rib, and/or along the leaf margin occur from early spring to fall (Fig. 1A). Initially, foliar lesions appear water-soaked (Fig. 1B) but eventually darken in color. The centers of lesions abscise from the leaf causing a shot hole appearance. Young leaves that are partially expanded are most susceptible to the development of symptoms as bacteria infested water may become trapped in the leaf, prolonging the leaf wetness period. In contrast, young leaves that have not expanded are not susceptible to bacterial spot because the leaf cells are too tightly packed together to allow the establishment of bacteria inside of the leaf. Premature leaf drop and leaf yellowing is common and can reduce fruit quality and size due to an increase risk of fruit sun burn and poor nutritional uptake (Fig. 1C & I). On fruit, the earliest lesions occur about three weeks after petal fall. Initially, lesions appear watersoaked and eventually become dark-brown as they enlarge and age. Early season fruit infections that occur before pit hardening develop lesions that extend deep into the fruit (Fig. 1F). Late season lesions that develop after pit hardening are shallow and may cause the skin to crack if the lesions coalesce (Fig. 1G). Bacterial spot lesions often favor secondary infection by the brown rot fungus, Monilinia fructicola, as well as other pre- and post-harvest fungal rots (Fig. 1H). Twig symptoms consist of cankers that initially appear water soaked and eventually enlarge, cracking the surface of the bark (Fig. 1E). Bacteria overwinter in these cankers that are first visible during bloom and serve as the primary source of inoculum in the spring. Bacteria are spread by wind-driven rain and require water, in the form of dew or rain, to infect the trees. Foliar infections, favored by warm wet weather, provide additional inoculum for secondary infections of leaves and fruit. Bacterial spot is a difficult disease to manage because there are few effective management strategies. Based on epidemiological studies conducted at Penn State University, management should be targeted at reducing the initial inoculum. Ways to reduce initial inoculum levels include removing overwintering cankers and applying copper in the spring and/or fall while trees are dormant. Applying dormant copper provides a prophylactic protection of trees against infection by the bacteria and reduce the inoculum that may remain on the surface of the tree before the bacteria overwinter in infected leaf scars and cankers in the fall as well as when bacteria become active in the spring. Cultural management strategies are also important and include selecting less susceptible cultivars; however, no cultivars is completely resistant to bacterial spot under favorable disease conditions. New trees should be planted in well-draining soils as well as areas free of ring nematodes. Weed and nutritional management will reduce the overall susceptibility of the trees to bacterial spot as well. In addition to removing overwintering cankers, pruning should be used to increase air flow within the canopy to reduce leaf wetness periods. Finally, various chemical bactericides may be used to reduce symptoms throughout the season and generally include copper and the antibiotic oxytetracycline. Applied at a 7 to 14 day interval, bactericides may be used less frequently when weather conditions do not favor disease development, such as when the weather is hot and dry. To avoid the development of antibiotic resistance, multiple chemistries should be used.

8 Fig. 1. Symptoms of bacterial spot A) Characteristic symptoms of bacterial spot including yellowing and angular lesions; B) New bacterial spot lesions that appear water soaked; C) Characteristic symptoms of nitrogen deficiency; D) Injury caused by copper; E) Bacterial spot canker lacking vegetative growth; F) Early season infection on peach occurs before pit hardening. Lesions extend deep into the fruit; G) Late season lesions develop after pit hardening, are shallow, and may cause the peach skin to crack when coalesced; H) Bacterial spot lesions favor secondary infection by the brown rot fungus, Monilinia fructicola; I) Severe premature defoliation of a peach tree puts fruit at risk of sunburn and premature fruit drop. 2 A B C D E F G H I

9 3 In 2014, several alternative bactericides and rotation programs were evaluated at Penn State s Fruit Research and Extension Center in Biglerville, PA (Table 1). These included FireLine (1.5lb/acre), MasterCop (copper sulfate pentahydrate) at 1.0 and 1.5 pt/acre, Kocide3000 (copper hydroxide) at 0.5lb/acre, MasterCop (1.0 pt/acre) rotated with Rampart (phosphorous acid) at 1.0 qt/acre, MasterCop (1.0 pt/acre) rotated with Serenade Optimum (Bacillus subtilis strain QST 713) at 14 oz/acre, MasterCop (1.0 pt/acre) and hydrated lime (2.0 lb/acre) mixed with vegetable oil (3.0 qt/acre), and MasterCop (1.0 pt/acre) mixed with vegetable oil. The vegetable oil was evaluated to reduce the phytotoxicity often associated with copper. The product evaluation site was a 4-cultivar ( Easternglo, Beekman, Snow King, and Sweet Dream ; Guard trees: Redhaven ) peach and nectarine block that was planted in The experimental block received standard fungicide and insecticide applications according to the commercial practices in the northeastern United States. Treatments were arranged in a randomized complete block with 4 replications. Treatments were applied using a boom sprayer at 400 psi, delivering 100 gal/a. Treatments were applied as follows: 1 = 12 May (Petal fall/shuck split); 2 = May (1C); 3= 2 June (2C); 4 = 16 June (3C); 5 = 25 June (4C); 6 = 7 July (5C); 7 = 22 July (6C). Overall, copper performed better than FireLine (oxytetracycline) at reducing disease severity on leaves and fruit. Vegetable oil did not effectively reduce the phytotoxicity associated with copper but the addition of hydrated lime and the rotation with Serenade Optimum did. The table shown is the combined results of all four cultivars. Table Evaluation of combined bacterial spot incidence and severity on leaves and fruit of 'Easterglo', 'Beekman', 'Sweet Dream' and 'Snow King' in the Penn State Fruit Research and Extension Center Peach and Nectarine Block. Leaves b Fruit c Treatment a Rate/Acre Timing Incidence d Severity Phytotoxicity Incidence Severity 1 Untreated a 4.1 a 0.2 g 89.6 a 10.6 a 2 FireLine 1.5lb a 3.4 b 0.2 g 84.8 ab 7.8 b 3 MasterCop 1.0pt bc 1.9 cd 6.3 b 75.5 de 6 cd 4 MasterCop 1.5pt c 1.8 cd 8.1 a 73 e 4.8 de 5 Kocide lb d 1.2 e 4.2 d 76.3 de 3.2 f 6 MasterCop 1.0pt 1,3,5, bc 2.1 cd 3.7 e 86.4 ab 6.7 bc Rampart 1.0qt 2,4,6 7 MasterCop 1.0pt 1,3,5, c 1.8 cd 3.1 f 74.7 de 4.2 ef Serenade Optimum 14oz 2,4,6 8 MasterCop 1.0pt c 1.5 de 2.7 f 80.0 cd 5.5 c-e hydrated lime 2.0lb vegetable oil 3.0qt MasterCopt + 1.0pt c 1.6 d 5.6 c 82.1 bc 6.4 c 9 vegetable oil 3.0qt a Application timings: 1 = 12 May (Petal fall/shuck split); 2 = May (1C); 3= 2 June (2C); 4 = 16 June (3C); 5 = 25 June (4C); 6 = 7 July (5C); 7 = 22 July (6C). Treatments were applied using a boom sprayer at 400 psi, delivering 100 gal/a. Standard insecticide and fungicide maintenance programs were applied to the entire orchard with an airblast or boom sprayer delivering 100 gal/a at 400 psi. b c d For foliar disease incidence and severity assessment, 5 shoots were randomly tagged and 10 leaves per shoot, starting from the base of the shoot, were assessed for percent bacterial spot incidence and severity (0-100%) twice during the season. The assessment shown here was taken in July At harvest (Easternglo on July 25, Beekman on August 5, and Snow King on August 11), 25 fruit per tree were assessed for percent bacterial spot severity by visually assessing the percent area of fruit covered with bacterial spot lesions. Disease incidence was also assessed. Values within columns followed by the same letter(s) are not not significantly different (P 0.05) according to Fisher's Protected LSD test.

10 Focus on Selected New Peach Varieties William Shane, Senior Extension Fruit Specialist Michigan State University, Southwest Michigan Research and Extension Center 1791 Hillandale Rd Benton Harbor, MI x shane@msu.edu The wide array of peach varieties available to growers makes it difficult to choose the best ones to buy. Over 70 varieties span the typical Michigan peach season from early July to late September, with each variety having a harvest window of a week to 10 days (Table 1). I am presenting here a quick summary of several newer peach varieties for these new harvest windows that present new options. Desiree is a new variety from Rutgers University in the Harrow Diamond harvest window about ripening about -25 days before Redhaven. This peach has nice size and flavor for the season but is showing in our tests at the SW Michigan Research and Extension Center (SWMREC) to be slightly some more cold bud tender than Harrow Diamond, Earlystar and PF-5D Big. Glenglo is a Loring sport that is popular in the eastern peach growing regions. Glenglo s claims to fame are good size and good color for a peach ripening approximately 2 weeks before Redhaven. Like Desiree, Glenglo is showing some decent but not good fruit bud hardiness, and some tendency for split pits when the crop is light. It has very good bacterial spot resistance. Summer Serenade, a better coloring Garnet Beauty sport, is a more reliable performer, but not as flavorful as Glenglo. Looking at the Redhaven window, Starfire is the uniform, nice coloring, reliable performer that is being challenged by PF9A-007 and PF Lucky 13. PF9A-7 has better size than Redhaven, but needs good light exposure to reach adequate skin color. PF Lucky 13 has nice flavor, colors better than PF9A-007, can have a crunchy texture, needs to have good thinning to size, and has a slight tendency for dropping fruit. In the Loring / PF17 season the new kid on the block is Sweetstar. Sweetstar has a vigorous, productive, tough tree. Fruit of Sweetstar size well, and the fruit hang well, retaining flavor, but can be somewhat irregular in shape. PF17 is well known for its excellent productivity and some tendency for fruit drop. Messina and PF are new selections in the Allstar, Coralstar, and Contender window. Contender has very reliable yielding, uniform fruit, and cans nicely but sometimes is medium quality as a fresh eating peach and shows rapid softening some years. Messina is relatively new, has nice size and flavor, but perhaps less reliable cropping than Allstar and PF Like Coralstar Messina has excellent sized fruit that need good light exposure to develop good skin color. Allstar has a long track record, is productive, and has attractive, nicely sized fruit. Experience so far with the newer PF has been good. In the old Cresthaven window, the reliable standby varieties are PF23 and Glowingstar. The newer variety PF24C Cold Hardy has a tough tree, but in our tests does not have appreciably better fruit bud hardiness than the \two previously mentioned varieties. PF24C Cold Hardy has nice handling and storage characteristics for the wholesale market. Gloria, also ripening in this window, is quite a bit different from the typical yellow peach due to its low acid flavor, and slow ripening characteristics. It, and sometimes Glowingstar, have had reports of being hard to peel by home canners. In the Fayette / Encore season there are several new options. PF has nice size, flavor, and excellent skin color for a late variety. Autumn Star has very good size, stores well with good quality with medium tree hardiness. Victoria is a late ripening, medium-colored Rutgers selection that is notable for its excellent flavor and storage characteristics. PF and PF Big George are varieties with firm, medium coloring, large fruit with good eating quality and good shelf life.

11 Table 1. Typical yellow melting flesh peach variety harvest windows for the Michigan climate. Revised November Older peach varieties Newer varieties with significant production Newest peach varieties Harbinger = -33* PF-1 = -30 Rich May = -28 Harrow Diamond = -25 PF-5B = -25 Desiree = -26 ^^ PF-5D Big = -22 ^^ Earlystar = -18 ^ PF Early 8 Ball = -17 ^^ Garnet Beauty = -10 Early Red Haven = -10 GaLa = -8 Sentry = -8 Glenglo = -13 PF-7 = -10 Summer Serenade = -10 PF 8 Ball = -10 PF-7A Freestone = -10 Rising Star = -8 Brightstar = -12 ^ PF Late 8 Ball = -5 ^^ Redhaven = 0 Reliance = 0 Vivid = +2 Bellaire = +3 PF-12A = +3 John Boy = +3 Glohaven = +8 Canadian Harmony = +10 Loring = +12 Suncrest = +12 PF 9A-007 = -2 PF 11 Peach = -2 PF 15A = +2 Blazing Star = +2 Starfire = +3 Redstar = +3 PF 14 New Jersey = +4 Blaze Prince = +8 Bounty = +10 PF 17 = +12 PF Lucky 13 = +6 ^ PF Super Duper = +8^^ John Boy II = +8 ^ SweetStar = +14 ^ Contender = +18 PF = +14 Allstar = +16 Coralstar = +16 Beaumont = +19 Messina = +17 ^^ Cresthaven = +24 Redskin = +26 PF 23 = +20 PF = +22 Glowingstar = +22 PF 24C Cold Hardy = +24 PF 25 = +26 PF = +20 ^^ July Prince = +24 ^^ PF Paramount = +24^^ Gloria = +26 ^^ LA Madison = +28 Harcrest = +28 Fayette = +28 Encore = +31 PF 27A = +30 PF = +32 Autumn Star = +37 ^ PF Fat Lady = +40 ^^ Laurol = +41 PF Big George = +50^^ Flame Prince = +38 ^^ PF Legendary = +41^^ Victoria = +47 ^^ PF Fashionably Late = +54^^ * = estimated harvest days before (-) or after Redhaven. Harvest order can change depending on the warm/cool characteristics of a season. A cooler year will delay harvest dates, a warmer season will compress the harvest dates closer together. ^ = little experience with this variety to date, ^^ = very little experience to date. LA = low acid type. Harvest order numbers are more tentative with newer selections.