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Fungicide Update For Apple Disease Management

Fungicide Update For Apple Disease Management. Janna Beckerman Department of Botany and Plant Pathology Purdue University janna@purdue.edu. SDHI fungicides and apple scab. S uccinate D e h ydrogenase I nhibitors

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Fungicide Update For Apple Disease Management

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  1. Fungicide Update For Apple Disease Management Janna Beckerman Department of Botany and Plant Pathology Purdue University janna@purdue.edu

  2. SDHI fungicides and apple scab • SuccinateDehydrogenaseInhibitors • High investment in this class of fungicide by Bayer, Dupont, BASF, Syngenta • And yet, Premixes Predominate • WHY DO YOU THINK? • Resistance • Efficacy • $$$ • Pristine was first SDHI available to fruit growers • registered in 2004 • Fontelis, Luna Sensation, Merivon were registered in 2013

  3. SDHI fungicides • SDHIs target an enzyme in the fungal respiration pathway • succinatedehydrogenase • Four SDHIs registered for tree fruit: • Boscalid– component of Pristine • Penthiopyrad– Fontelis • Fluopyram – component of Luna Series • Fluxapyroxad – component of Merivon

  4. SDHI fungicides for apple scab • SDHIs are very good-excellent scab materials • Especially if you have SI resistance • High resistance risk • act like strobilurins in terms of resistance development • Mutation to resistance will confer high level of resistance • We need to be highly proactive with fungicide resistance management tactics

  5. SDHI efficacy – 2009 [Sundin MSU] % fruit scab- McIntosh def g cdef fg a cdef efg defg 6 EBDC 6 lb 2 EBDC 4 lb 3 Flint 2 oz 1 EBDC 6 lb 2 EBDC 4 lb 3 Fontelis 14 oz 1 EBDC 6 lb 2 Scala 7 oz 4 Flint 2 oz Control 6 Flint 2 oz 2 Scala 7oz 4 Luna Sensation 4oz 2 EBDC 4 lb 3 Fontelis 20 fl oz 1 EBDC 6 lb

  6. SDHI Efficacy – % Fruit ScabPenthiopyrad (Fontelis) Penthio + EBDC EBDC Nontreated Control Year 14 fl oz/A 20 fl oz/A 3 lb/A 2007 95.2 a 1.0 f 2.8 f 2008 100.0 a 2.1 gh 1.0 gh 8.9 e 6 applications for primary scab; ~ 10 day schedule Fruit scab rated in August

  7. Fluxapyroxad and Merivon efficacy, 2010

  8. Merivon Efficacy – Apple ScabEast Lansing, 2011 a % fruit scab b c c c c 6 Merivon + EBDC 5.5 fl oz/A + 3 lb 6 Merivon 4 fl oz/A 2 Vangard + EBDC 3 Flint 2 oz/A 6 Merivon 5.5 fl oz/A 6 Pristine 14.5 oz/A Control

  9. Luna Efficacy – Apple ScabFremont, MI (commercial orchard) a % fruit scab b bc c c 4 Luna Sensation + EBDC 4 fl oz/A + 3 lb Control 2011

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  11. SDHI fungicides for apple scab • Fontelis, Luna Tranquility, Merivon are all performing very well for scab control • Fungicide resistance management – protect these SDHIs by tank-mixing with 3 lb/A EBDC • Do not use SDHIs after infection • Do not use Merivon with oil – potential for leaf phytoxicity

  12. Fontelis-Captanphytoxicity controversy, 2013 • Captan – broad-spectrum, contact fungicide that kills fungal spores • Surface-associated fungicide • Captan is also toxic to plant cells if it penetrates into leaf or fruit tissue • Spray oil or other spray adjuvants that act as penetrants allow captan to move through the protective waxy cuticle on plant surfaces • Damage in NY noted on only a very, very small percentage of total acreage treated with Fontelis-Captan • Applications made under slow-drying conditions or with low volumes of water (< 100 gallons/acre) increased the probability of injury

  13. Fontelis-Captanphytoxicity controversy, 2013 ‘Mutsu’ ‘Golden Supreme’

  14. Captan injury • Captan-associated leaf spotting • Usually on the 2 or 3 leaves on a terminal that were just unfolding when the trees were sprayed • Unfolding leaves most susceptible because it takes time for the cuticle layer to form on new leaves • By the time the injury becomes visible, the injured leaves may be 5-6 nodes below the growing point • Russeting on fruit

  15. Captan injury • Usually appears during the three weeks after petal fall • Rapid terminal growth, lots of new leaves • Spray tanks at this timing can contain insecticides, foliar nutrients, growth regulators, spray adjuvants ….. • If any of these additional materials enhances captan uptake into leaves, injury will result

  16. Fontelis-Captan controversy, 2013 • Damage in NY noted on only a very, very small percentage of total acreage treated with Fontelis-Captan • Applications made under slow-drying conditions or with low volumes of water (< 100 gallons/acre) increased the probability of injury • Possibility for damage seems to center on the petal fall, 1st cover timings • Mancozeb (EBDCs) is a perfectly acceptable contact fungicide for use at these timings • If Fontelis is used at these timings, tank mix with Mancozeb instead of captan

  17. http://www.youtube.com Search “tree fruit pathology”

  18. Youtube videos http://www.youtube.com Search: treefruit pathology

  19. Fungicides and Apple Scab • Protectant program – Captan + EBDC • Protective barrier to infection, no resistance issues • Requires more frequent spraying • No curative action – can be defeated by heavy rains, lengthy wetting periods, conditions that prevent access to orchards • Weak on other diseases including powdery mildew and black rot

  20. Fungicides and Apple Scab • Protectant program – Captan + EBDC • “Captozeb” • 3 lb Captan 80WDG – (note this is more than a half rate) • 3 lb EBDC • Could go even higher with Captan in advance of rains • Captan is more effective than EBDCs for scab control, but more susceptible to washoff by heavy rain • EBDCs have better retention, redistribution

  21. Fungicides and Apple Scab • Syllit – Dodine– early only (+ EBDC) or once in 5 yr rescue—DEPENDS UPON YOUR RESISTANCE STATUS • Sterol Inhibitors (DMIs) • Nova, Procure • 2nd generation – Inspire Super, Indar, Topguard • Anilinopyrimidines • Vangard, Scala • Strobilurins (QoIs) – Flint, Sovran-Depends upon Resistance • SDHIs • Luna, Fontelis, Merivon

  22. SDHI’s and Apple Scab, Summary • Efficacy of all three materials is very good to excellent; HOWEVER: • All must be tank-mixed with a protectant for resistance management • Company mixing partner for fluopyram and fluxapyroxad is a stroby (QoI) • Resistance widespread in MI and NY and increasing in IN and IL

  23. Key Symptoms of Fungicide Resistance • You should suspect resistance if you have good control throughout most of the orchard EXCEPT on cultivar specific blocks • McIntosh is a canary in the coal mine. • Fungicide failure will look like extreme scab, with all cultivars having scab, not just McIntosh

  24. Fungicide premixes • Pre-packaged fungicide combos • Ex. Inspire Super – mix of 2nd-generation DMI + AP (Vangard) • Luna Sensation (Bayer) • SDHI fluopyram + Flint (QoI) • Merivon (BASF) • SDHI fluxapyroxad + pyraclostrobin (QoI)

  25. Fungicide premixes • Pre-packaged fungicide combos • Ex. Inspire Super – mix of 2nd-generation DMI + AP (Vangard) • Luna Sensation (Bayer) • SDHI fluopyram + Flint (QoI) • Merivon (BASF) • SDHI fluxapyroxad + pyraclostrobin (QoI) ISSUE #1 – sub-optimal mixing partner

  26. Fungicide premixes ISSUE #1 – sub-optimal mixing partner • Luna Sensation (Bayer) • SDHI fluopyram + Flint (QoI) • Merivon (BASF) • SDHI fluxapyroxad + pyraclostrobin (QoI) • Strobilurins (QoIs) – were once a very good class of scab fungicides • CURRENT: resistance widespread in Michigan, increasing in NY, occurring in IN

  27. Fungicide premixes ISSUE #2 – lower rates incorporated in premixes • Luna Sensation (Bayer) • SDHI fluopyram + Flint (QoI) • Flint – rate when used alone is 2 oz/A • Luna Sensation label – 4.0 to 5.8 fl oz/A • Flint equivalent is 1.05 to 1.52 oz/A

  28. Fungicide premixes ISSUE #3 – wide rate ranges on labels • Luna Sensation label – 4.0 to 5.8 fl oz/A • SDHI fluopyram + Flint (QoI) • Flint equivalent is 1.05 to 1.52 oz/A • Merivon label – 4.0 to 5.5 fl oz/A • Different SDHI BUT • Flint equivalent is 1.05 to 1.52 oz/A • USE HIGHEST LABEL RATE!!

  29. Fungicide premixes – rate effects 2011 trial – MSU 6 applications • Merivon 4.0 fl oz + 3 lb Manzate • Merivon 5.5 fl oz + 3 lb Manzate • Untreated control • USE HIGHEST LABEL RATE!! Fruit infection 8-17-11 4.3% 0.5% 100.0%

  30. Fungicide Resistance Management Janna Beckerman Purdue University janna@purdue.edu 765-494-4628

  31. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • KILL the pathogen • KILL the pathogen

  32. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • Rotation of modes of action and tank-mixing with broad-spectrum protectants

  33. Help with Rotations • Soon to be updated to include SDHI fungicides

  34. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • Rotation of modes of action and tank-mixing with broad-spectrum protectants • Insist on 100% control of disease early in season (GT to TC) to keep population levels down

  35. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • Rotation of modes of action and tank-mixing with broad-spectrum protectants • Insist on 100% control of disease early in season (GT to TC) to keep population levels down • “Catching up” is a bad strategy doomed to fail!

  36. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • Rotation of modes of action and tank-mixing with broad-spectrum protectants • Control disease early in season to keep population levels down • Avoid after-infection applications

  37. Schematic representation of how fungicides work Visible Symptoms sporulation Infection Antisporulant Eradicant Protectant Curative

  38. Fungicide Resistance Management(Prevention) • Critical issues: • KILL the pathogen • Rotation of modes of action and tank-mixing with broad-spectrum protectants • Control disease early in season to keep population levels down • Avoid after-infection applications • Reduce over-wintering inoculum with urea or flail mowing

  39. Late Fall/Early Spring Overwintering Inoculum Treatment

  40. Reduce overwintering inoculum • Where scab was present last year on leaves or fruit, apply urea at 40 lb/A to the orchard floor before green-tip. • Urea will reduce ascospore numbers by 60-90%. • One spray converts a high-inoculum orchard into a low-inoculum orchard. • The urea application is cheap compared to fungicides or fruit scab! • keep in mind you are adding app. 23 lbs. of actual nitrogen per acre to the orchard • adjust your fertilizer program accordingly. • A urea spray will have no value in orchards that had no scab last year • Flail mowing is also effective

  41. Urea and Overwintering Scab • 40 lbs urea (greenhouse grade) in 100 gallons water • 100 gallons per acre • Turn off top nozzles on sprayer • Spring application –Suppresses ascospore development • Can apply right up to trees breaking dormancy • Great option in cold climate • Inoculum reduction is becoming more and more critical with fungicide resistance issues

  42. Scab – Inoculum reduction strategies for 2014 Inoculum reduction —Apply urea to fallen leaves in fall or spring Flail mowing in spring Results of Urea trials: -- Sprayed leaves on trees 12 Oct: 97% spore reduction -- Fall ground spray, early Nov.: 42-58% reduction. -- Spring ground spray: 70% avg. reduction; range 44-86%. Conclusions: -- Spring application provided most consistent results although Better coverage was obtained in canopy sprayed leaves. Sutton, D.K., Mac Hardy, W.E., and Lord, W.G. 2000. Effects of shredding or treating apple leaf litter with urea on ascospore dose of Venturiainaequalisand disease buildup. Plant Dis. 84 1319-1326.

  43. How not to let … Get up yours!

  44. Scab Control Issues:Overwintering inoculum Risk of primary scab infection based on ascospore maturity and increasing leaf area. RISK ST GT HIG TC PINK BLOOM PF 1st C APPLE GROWTH STAGE

  45. Fungicides are more effective in low-inoculum orchards • less risk in using reduced rates of fungicides in spring • e.g., 3 lb/A of mancozeb by itself • 2 lbscaptan • Early copper spray (before green tip) • Sanitation is rarely 100% effective for controlling apple scab • some fungicide sprays are still needed • Sanitation may prove cost-effective in years when diseases subsequently reach epidemic proportions, • sanitation is unlikely to be cost-effective in dry years when there is little disease pressure.

  46. Use protectants wisely • Copper applied at green-tip can substitute for a mancozeb spray for scab control • 3 lb/A COCS (mid-rate) has same activity as 3 lb/A mancozeb. • In most cases, mancozeb at 3 lb/A or captan-80 at 2 lb/A will provide good control of scab in green-tip sprays (where copper is not used) and half-inch green sprays. • For these early sprays, trees need coverage, but lower rates are usually effective. • Tip: Save your mancozeb and use copper for the GT spray –you kill two disease problems with one application.

  47. Timing is everything: Start at Silver tip • Sanitation via inoculum reduction. • Use copper at silver tip-bonus fire blight management • Protect green tissue first! • Timing during bloom to ensure trees are adequately protected during peak susceptibility AND ascospore discharge • primary infections that became established early in the season will begin producing conidia during bloom. • "Stretching" spray timing just a few days so one can reach petal fall can be a costly mistake if trees are left unprotected during critical bloom-time infection periods

  48. Scab spore load in high-inoculum orchards RISK Conidia!!! ST GT HIG TC PINK BLOOM PF 1st C APPLE GROWTH STAGE

  49. Effects of Apple Scab Inoculum Dose High-inoculum orchard: 20% leaf scab in autumn Ascospores released Difference in areas under the curves: 6,857 X Low-inoculum orchard: <1% scab in autumn ST GT HIG TC PINK BLOOM PF 1st C APPLE GROWTH STAGE

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