Cercospora Leaf Spot. Fungicide Resistance and 2018 Recommendations. Mark Bloomquist SMBSC

Transcription

1 Cercospora Leaf Spot Fungicide Resistance and 2018 Recommendations Mark Bloomquist SMBSC

2 Review of 2017 Season Cultural Practices to Reduce CLS Potential CLS Fungicide Resistance Sample Results 2017 CLS Fungicide Trial Results 2018 CLS Fungicide Recommendations

3 Large amount of CLS inoculum from Favorable Disease Conditions. Disease Index Values

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5 Large amount of CLS inoculum from Favorable Disease Conditions. Dramatically better control of the disease in 2017.

6 2016 Season 90% of fields brown $ /acre $300 X 108,000= $30+ million loss to SMBSC

7 2016 Season 90% of fields brown $ /acre $300 X 108,000= $30+ million loss to SMBSC 2017 Season 20% of fields brown $ /acre $300 X 25,000 = $7.5 million loss to SMBSC

8 Large amount of CLS inoculum from Favorable Disease Conditions. Dramatically better control of the disease in Inoculum load for 2018 still a large concern.

9 Lower Favorability for Disease. Reduce selection pressure on fungicides. American Phytopathological Society

10 Variety Tolerance SMBSC Seed Policy Change

11 SV Beta Beta Beta Hilleshog Crystal M Beta Maribo MA109RR 4.3 Crystal RR Hilleshog 9093RR 4.3 Crystal M Beta 92RR SV RR Beta Crystal M Crystal M

12 Variety Tolerance Management of 2018 Fields with Common Lines to 2017 Fields

13 Disease often begins along common lines Separation from common lines to 2018 Fields Plant alternate crop for along common line. Plant variety with Strong CLS tolerance in first feet along 2017 common line. Early fungicide application along common line 1-2 sprayer passes along common line Apply EBDC 7-10 days prior to CLS program beginning.

14 Inoculum moved with water from 2016 field. Do you have areas in your 2018 fields where this could happen. Plant most resistant varieties in these areas if planted to sugar beets.

15 Do not drag residue from a 2017 field into your 2018 sugar beet fields Jeremie Larson, Reynolds, ND photographer Mike Doeden, Agriculturist - ACS

16 Variety Tolerance Common Lines to 2017 Fields Fungicide Applications and Resistance Managment

17 Favorable disease conditions Polycyclic fungus Several generations per year. Repeated fungicide applications Creates High Selection Pressure on fungus

18 Fungicide Class QoI (Strobilurins) Headline,Gem, Priaxor Benzimidazoles (Topsin) Triazoles (Proline, Minerva, Inspire, Enable, EminentVP) Tin EBDC Copper FRAC Risk of Resistance High High Medium Low - medium Low Low Fungicide Resistance Action Committee (2016)

19 Leaf samples taken from 181 fields by Agricultural Staff. Samples sent to Dr. Gary Secor s Lab at North Dakota State University. Analyze samples for resistance to several commonly used fungicides. Project funded by Sugar Beet Research and Education Board of MN and ND.

20 % of Samples Qol Fungicides Susceptible < 50% 50% 100% Resistant Secor (2017)

21 % of Samples CLS Samples Qol Fungicides Susceptible < 50% 50% 100% Resistant Secor (2017)

22 EC50 Value Triazole Average EC50 Value Tetraconazole Prothioconazole

23 Percent of Field Samples Percent of Field Samples with EC50> Tetraconazole Prothioconazole

24 Percent of Field Samples Percent of Field Samples with Resistance at 1ppm Tin

25 Percent Germination CLS Spore Germination at 1ppm Tin

26 Single-mode Trial and Program Trial. Planted April 25 Commercial Variety Six row plots Treat center 4 rows. Trial is inoculated with ground up CLS infected leaves from 2016 season. Five application timings. Foliar Ratings taken (1-9 scale). Harvested for yield and quality. (Sept. 30)

27 Untreated Check 5 Spray Tank-mix Program

28 Untreated Check

29 Untreated Check Strobilurin Fungicide (Priaxor)

30 Triazole (Proline)

31 Triazole (Proline) Triazole (Proline) + EBDC

32 Triazole (Proline) Triazole + Copper

33 Tin Tin + EBDC

34 Tin Tin + Copper

35 Incorporate results of Single-Mode Trials into a full CLS fungicide program. Alternate products. Six row plots with center 4 rows treated.

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37 Treatments: 1. Tin 2. Triazole 3. Tin 4. Triazole 5. Tin Cost - $ 52 Treatments 1. Tin + Topsin 2. Triazole + Copper 3. Tin + EBDC 4. Triazole + EBDC 5. Tin + Copper Cost - $96

38 Sugar Tons/Acre Ext. Sugar/Acre Check 14.2 a 23.3 a 5418 a No Tank-Mix 15.6 b 27.9 b 7298 b SMBSC Tank-Mix 16.4 bc 32.8 c 9126 c Recommendation

39 Cost of Treatment Revenue/Acre Above Check Check $0 $0 a No Tank-Mix $52 +$345 b SMBSC Tank-Mix $96 +$669 c Recommendation

40 Cost of Treatment $52 Cost of Treatment $96 Return over No Tank-mix Treatment +$324

41 Provide a second Mode of Action Decrease Selection Pressure on CLS fungus Will be necessary for both Cercospora control and resistance management for Potential tank-mix partners

42 Benzimidazoles ( Ex.Topsin and T-Methyl) Dry and Flowable formulations 1 application per season EBDC (Ex. Manzate and Dithane) Dry and Flowable formulations Copper (Ex. Badge SC and Kocide) Copper Hydroxide and Copper Oxychloride formulations have been most effective. Copper sulfate may be less effective?

43 No glyphosate Mixing order is important Based on formulation Flushing spray booms and lines

44 Sticker/Spreader adjuvants recommended on some fungicide product labels. Products such as MasterLock and Cerium Elite was first year of trials in SMBSC. No negative effects seen from adjuvant treatments. Continue testing in 2018.

45 Apply glyphosate 7-10 days prior to canopy 1. Tin + Topsin 2. Triazole + Copper 3. Tin + EBDC 4. Triazole + EBDC 5. Tin + Copper 6. Triazole + EBDC **All fungicide applications on a day spray interval

46 Apply glyphosate 7-10 days prior to canopy 1. Tin + Topsin 2. Triazole + Copper 3. Tin + EBDC 4. Triazole + EBDC 5. Tin + Copper 6. Triazole + EBDC *2018 CLS Fungicide program as of January If additional tools become available prior to season, we will update the program.

47 Mid-August harvest is the new normal for SMBSC. Fungicides have varying pre-harvest intervals. Fungicide coverage must be maintained on acres that will not be early harvested. Plan ahead to lessen conflicts with pre-harvest intervals.

48 Application Products Approximate Cost/Acre 1 Tin + Topsin $12 2 Triazole + Copper $21 - $29 3 Tin + EBDC $12 - $17 4 Triazole + EBDC $19 - $32 5 Tin + Copper $12 - $18 6 Triazole + EBDC $19 - $32 Total $95 - $140 / Acre

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