Fungicide modes of action for field crops. Dr. Mary Burrows Montana State University Plant Sciences and Plant Pathology Department

Transcription

1 Fungicide modes of action for field crops Dr. Mary Burrows Montana State University Plant Sciences and Plant Pathology Department

2 What do I need to do BEFORE deciding a fungicide application is necessary?

3 Schutter Diagnostic Lab Identify plant diseases, insects, weeds/plants, mushrooms, toxic molds, etc. Provide management recommendations Education and outreach on plant pests Process approximately 2000 samples/yr (~50% homeowner/horticulture)

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5 Mobile phone platform for fluorescence imaging of nanoparticles and stretched ssdna J. Contreras-Naranjo et al IEEE J. Sel. Topics in Quantum Electronics. v. 22.

6 Sign up for a FREE account to receive sugarcane aphid alerts and notifications when it has been detected near you! Visit to learn more! c. Wendy Johnson, KSU

7 Fungicides What is a fungicide and how does it work (conventional and organic options)? What does MOA mean? Fungicide resistance What products are available and how do I find them? Economics of fungicide use

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9 Fungicide classes Number of classes of common pesticides for field crops Herbicide = ~16 classes Insecticide = ~17 classes Fungicide = 4-6 classes

10 Fungicide systemicity Non-systemic Systemic Do not penetrate into plant Redistribute on plant surfaces Multi-site inhibitors Kills spores/inhibits germination Protectant only Broad spectrum Penetrate into plant Redistribute on & within plants Single-site inhibitors Inhibits spore germination and or mycelial growth Protectant and curative Selective

11 Non-systemic/Multi-Site Single Site v. Multi-site Systemic v. non-systemic Systemic/Single Site Protectant only Can wash off Shorter application intervals Broad spectrum Low Risk of Resistance Protectant and curative Less prone to washing off Longer application intervals Selective High Risk of Resistance

12 Specific fungicides target different sites and biochemical processes Cell membrane DMI triazole fungicides General cell constituents chlorothalonil Microtubules thiophanate methyl Nucleic acids Mefenoxam and metalaxyl Mitochondria QoI (azoxy-, pyraclo-, trifloxy-, fluoxa-) SDHI (fluxapyroxad, boscalid) Cell wall Modified from Rick Latin

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14 Contact Strobilurins Triazoles Carboxamides Common names Bravo, Thiram, Copper, Sulfur, oils Stamina, Headline, Quadris Tilt, Folicur, Proline Vibrance, Boscalid, Xemium (Priaxor) Mode of action FRAC group M: Multiple sites of action FRAC group 11: QoI (quinone outside) inhibitors (respiration); spore germination, penetration, and mycelial growth FRAC group 3 : DMI (demethylation) inhibitors; biosynthesis of sterols in fungal cell membrane; spore penetration and mycelial growth FRAC group 7: SDHI (succinate dehydrogenase inhibition; Respiration; aka carboxamides) new 2 nd generation SDHIs Residual Low Depends on the specific product; days Resistance development Low High (specific MOA) Mobility in plant None Translaminar and systemic Protection Contact only Protective only (kill germinating spores) Medium High systemic activity Protective and curative High; Practice good resistance mgmt tactics Carboxamide not systemic (targets later-season applications) Protective Senescence Delayed Note: these are generalizations about Potentially fungicide delayed classes

15 Triazoles Medium Risk Strobilurins High Risk Group M (contact fungicides) Low Risk SDHI inhibitors High Risk

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17 Spore germination Penetration Mycelial growth Germ tube formation Sporulation Carboxamides Strobilurins Triazoles (SDHIs) (QoIs) (DMIs) Fungicide efficacy No efficacy Disease symptoms

18 Fungicide movement in the plant From: Tenuta, A., D. Hershman, M. Draper and A. Dorrence Using foliar fungicides to manage soybean rust.. Land-Grant Universities Cooperating NCERA-208 and OMAF. Available online at

19 Fungicide modes of action: Strobilurins FRAC group 11 QoI (quinone outside) inhibitors (respiration); spore germination, penetration, and mycelial growth Provides days of protection High risk of resistance development because it has a very specific mode of action (they block electron transfer at the site of quinol oxidation (the Qo site) in the cytochrome bc 1 complex, thus preventing ATP formation) Originally isolated from wood-rotting fungi Strobilurus tenacellus Reduced-risk pesticide (pose less risk to human health than other chemical options at the time of registration by EPA) Control a wide array of fungal diseases Excellent preventative fungicides, but limited curative effects Plant health benefit independent of disease control?

20 Figure 1. Mobility of trifloxystrobin, an example of a QoI fungicide. /Strobilurin/top.htm

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23 Compare sprayed and unsprayed plots

24 Control (no fungicide), 14 daa

25 Strobilurin fungicides, 14 daa Headline Gem 500 SC

26 Strobiliurin + Trizole, 14 daa Quilt Quilt Xcel

27 Strobiliurin + Trizole, 14 daa Twinline Prosaro

28 Trizole fungicides, 14 daa Alto Caramba Proline

29 Fungicide resistance development Fungal spore with mutation that confers RESISTANCE to fungicide MOA Fungal spore susceptible to fungicide MOA

30 Fungicide resistance development Fungal spore with mutation that confers RESISTANCE to fungicide MOA Fungal spore susceptible to fungicide MOA When a fungal population is predominately RESISTANT to a fungicide MOA, chemical failures may occur

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35 Biological and OMRI approved fungicides in pulses, 2016 Trade name Active ingredient Mfr. Phosphorous acid, mono- and dibasic sodium, potassium, Nufarm Agricultural ALUDE FUNGICIDE and ammonium salts Products BADGE SC Copper hydroxide; Copper oxychloride Isagro USA, Inc. CONFINE EXTRA Phosphorous acid, mono- and dipotassium salts Winfield Solutions KALIGREEN FUNGICIDE Potassium Bicarbonate Otsuka Chemical Co. KOCIDE 3000 Copper hydroxide DuPont KUMULUS DF Sulfur Arysta OXIDATE 2.0 Hydrogen dioxide; Peroxyacetic Acid BioSafe Systems REGALIA (CAUTION) Extract of Reynoutria sachalinensis Marrone Bio Innovations ACTINOVATE Streptomyces lydicus WYEC 108 Natural Industries, Inc. ROOTSHIELD GRANULES Trichoderma harzianum Rifai strain KRL-AG2 BioWorks, Inc. BIO-TAM Trichoderma asperellum (ICC 012); Trichoderma gamsii (ICC 080) AgraQuest, Inc. ROOTSHIELD PLUS WP Trichoderma harzianum Rifai strain T-22; Trichoderma virens strain G-41 BioWorks, Inc. SERENADE ASO Bacillus subtilis strain QST 713 AgraQuest, Inc./Bayer SONATA FUNGICIDE Bacillus pumilus strain QST 2808 Bayer CDMS.net

36 Organic fungicides

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38 Sulfur Ancient Greeks used against rust disease Powdery mildew Prevents fungal spores from germinating Sulfur + oil (within a month) = phytotoxic Lime-sulfur is a dormant spray, more effective at lower doses but smells bad

39 Copper Efficacy against fungi and bacteria Copper sulfate + lime = Bordeaux mixture (safener, reduces phytotoxicity) Can persist through rain More phytotoxic at high temperatures >85F and if rain occurs very soon after application Copper especially phytotoxic on young tissue

40 Horticultural and neem oils Mostly used for insects Can minimize virus spread by piercingsucking insects Can help control thrips and spread of associated viruses (INSV, TSWV ) Can be used to manage powdery mildew Check phytotoxicity on plants before widespread application Do not apply <40F or >90F; best if RH <65% so oil can evaporate quickly and reduce phytotoxicity

41 Bicarbonates Baking soda = sodium bicarbonate Can be effective when used with oil Sodium can build up in soil and become toxic to plants Different bicarbonate salts have different effects on plants and diseases Ammonium and potassium bicarbonate preferred because of added nutrients to plants and lack of sodium

42 Biocontrols

43 Biological and OMRI approved fungicides in pulses, 2016 (from CDMS) Trade name Active ingredient Mfr. Phosphorous acid, mono- and dibasic sodium, potassium, Nufarm Agricultural ALUDE FUNGICIDE and ammonium salts Products BADGE SC Copper hydroxide; Copper oxychloride Isagro USA, Inc. CONFINE EXTRA Phosphorous acid, mono- and dipotassium salts Winfield Solutions KALIGREEN FUNGICIDE Potassium Bicarbonate Otsuka Chemical Co. KOCIDE 3000 Copper hydroxide DuPont KUMULUS DF Sulfur Arysta OXIDATE 2.0 Hydrogen dioxide; Peroxyacetic Acid BioSafe Systems REGALIA (CAUTION) Extract of Reynoutria sachalinensis Marrone Bio Innovations ACTINOVATE Streptomyces lydicus WYEC 108 Natural Industries, Inc. ROOTSHIELD GRANULES Trichoderma harzianum Rifai strain KRL-AG2 BioWorks, Inc. BIO-TAM Trichoderma asperellum (ICC 012); Trichoderma gamsii (ICC 080) AgraQuest, Inc. ROOTSHIELD PLUS WP Trichoderma harzianum Rifai strain T-22; Trichoderma virens strain G-41 BioWorks, Inc. SERENADE ASO Bacillus subtilis strain QST 713 AgraQuest, Inc./Bayer SONATA FUNGICIDE Bacillus pumilus strain QST 2808 Bayer CDMS.net

44 c. R. Sisco, UC-Davis WRIR4

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47 45 products for wheat 20 Apr, 2016

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49 MSU fungicide trials in dryland WW trials 4 reps/trial, all harvested with a research combine One location, one year there was a statistically significant increase in yield with the use of a fungicide on dryland wheat in the absence of disease

50 Fungicide use in winter wheat NO/minimal disease, Number of observations (plots) Number of observations (plots) Avg. Yield (Bu/A) Avg. Yield Bozeman (Bu/A) Havre Average Average Hill Co. (Kremlin) Conrad Chouteau Co (Loma) Average Moccassin Total

51 Difference in yield from the control due to fungicide (Bu/A) Overall, a 37% chance you will get 2 Bu/A yield increase due to fungicide 2 Bu/A Difference in yield (Bu/A) due to fungicide application as compared to the control

52 Fungicide use in winter wheat NO/minimal disease Tillering Flag Flowering Number of observations (plots) Avg yield compared to the control (Bu/A) Strobilurin Triazole SDHI Blend Average Strobilurin Triazole Blend Average Blend Average Multiple Strobilurin Blend Average Total

53 Fungicide use in winter wheat NO/minimal disease Number of observations (plots) Avg yield compared to the control (Bu/A) Tillering Full Half Quarter Average Flag Full Half Average Flowering Full Average Multiple Full Half Average Total

54 fungicide/index.html

55 Fungicide 1 Fungicide 2 What do you notice to be skeptical Fungicide 3 about? Stats? How many treatments total? Location?

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