Fungicide Resistance Survey in California

Transcription

1 Fungicide Resistance Survey in California S.D. Cosseboom 1, G. Schnabel 2, K.L. Ivors 1, and G.J. Holmes 1 1 Strawberry Center, California Polytechnic State University; 2 Clemson University, SC

2 Outline Fungicide resistance survey Fungicide use survey Fungicide resistance trial Conclusions Disease management options Resistance management strategies

3 Production (millions of trays) California production regions Northern district Central district Southern district 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month

4 40 Ranches 10 Isolates/ Ranch 2 sampling times

5 20 Production (millions of trays) Northern district Central district Southern district 2 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Early-season sampling Late-season sampling

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7 Table. Fungicides labeled for Botrytis gray mold of strawberry in California Example trade name Active ingredient(s) FRAC code(s) Topsin Thiophanate-methyl 1 Rovral Iprodione 2 Fontelis Penthiopyrad 7 Kenja 400 Isofetamid 7 Luna Sensation Fluopyram Trifloxystrobin 7 11 Luna Tranquility Fluopyram Pyrimethanil 7 9 Pristine Boscalid Pyraclostrobin 7 11 Merivon Fluxapyroxad Pyraclostrobin 7 11 Scala Pyrimethanil 9 Switch Cyprodinil Fludioxonil 9 12 Elevate Fenhexamid 17 Ph-D Polyoxin-D 19 active ingredient was not tested in this study

8 No fungicide Cyprodinil Iprodione Fludioxonil Fernández-Ortuño, D. et al Fenhexamid T-methyl Boscalid Fluopyram Penthiopyrad Isofetamid Experimental 1 Experimental 2

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11 Boscalid Fludioxonil Fenhexamid Control

12 California conventional Early-season (n=340) Late-season (n= 362) Frequency of resistance (%) T-methyl Iprodione Boscalid Penthiopyrad Isofetamid Fluopyram Cyprodinil Pyraclostrobin* Fludioxonil Fenhexamid Active ingredient * Early-season n=73; Late-season n=342 FRAC code

13 100 California organic Early-season (n=92) Late-season (n=94) Frequency of resistance (%) T-methyl Iprodione Boscalid Penthiopyrad Isofetamid Fluopyram Cyprodinil Pyraclostrobin* Fludioxonil Fenhexamid Active ingredient FRAC code * Early-season n=21; Late-season n=83

14 Strawberry nursery 100 Frequency of resistance (%) T-methyl Iprodione Boscalid Penthiopyrad Isofetamid Fluopyram Cyprodinil Pyraclostrobin* Fludioxonil Fenhexamid Active ingredient FRAC code n=10

15 FUNGICIDE USE SURVEY Product Trilogy Ph-D Merivon Prev-Am Ultra Fontelis Scala Elevate Pristine 1.8 Switch 2.3 Captan Avg. no. applications/season Figure 3. Average number of applications/season of the top ten most frequently applied fungicides labeled for gray mold of strawberry in 32 California strawberry farms in 2016.

16 Fungicides applied weekly No fungicides applied Week Sampling time Field fungicide treatments 1) Non-treated control 2) Elevate (fenhexamid) (E) 3) Switch (cyprodinil + fludioxonil) (S) 4) Pristine (boscalid + pyraclostrobin) (P) 5) Captan (C) 6) P, S, E rotation 7) P+C, S+C, E+C rotation Photo by: B. Liu Resistance testing 4 media types 1) non-amended control 2) Endura (boscalid) 3) Scholar (fludioxonil) 4) Elevate (fenhexamid)

17 Fungicides applied weekly No fungicides applied Week Sampling time Field fungicide treatments 1) Non-treated control 2) Elevate (fenhexamid) (E) 3) Switch (cyprodinil + fludioxonil) (S) 4) Pristine (boscalid + pyraclostrobin) (P) 5) Captan (C) 6) P, S, E rotation 7) P+C, S+C, E+C rotation Photo by: B. Liu Resistance testing 4 media types 1) non-amended control 2) Endura (boscalid) 3) Scholar (fludioxonil) 4) Elevate (fenhexamid)

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19 Sensitivity to fenhexamid Frequency of resistance (%) Week / Selection pressure 0 / off 3 / on 6 / on 9 / off 12 / off Elevate UTC Treatment / Week

20 Sensitivity to fenhexamid Frequency of resistance (%) Week / Selection pressure 0 / off 3 / on 6 / on 9 / off 12 / off Elevate UTC Treatment / Week

21 Sensitivity to fenhexamid Frequency of resistance (%) Week / Selection pressure 0 / off 3 / on 6 / on 9 / off 12 / off Elevate UTC Treatment / Week

22 Sensitivity to fludioxonil Frequency of resistance (%) Week / Selection pressure 0 / off 3 / on 6 / on 9 / off 12 / off Switch UTC Treatment / Week

23 Sensitivity to boscalid Frequency of resistance (%) Week / Selection pressure 0 / off 3 / on 6 / on 9 / off 12 / off Pristine UTC Treatment / Week

24 Fungicide Resistance Genotypes FRAC code Chemical Class Gene Genotype observed 17 Hydroxyanilides ERG27 F196C, F412I, F412S 2 Dicarboximides Bos1 I356N, I365N, I365S 1 MBCs Beta-tubulin E198A 11 QoIs Cytochrome b G143A 7 SDHIs SDHb H272R, H272Y, N230I, P225F SDHI Resistance Boscalid Fluopyram Penthiopyrad Isofetamid Mutation in SDHb R H272R R - R - H272Y R R R - N230I R R R R P225F

25 SDHI Resistance Boscalid Fluopyram Penthiopyrad Isofetamid Mutation in SDHb R H272R R - R - H272Y R R R - N230I R R R R P225F

26 Disease control and resistance management Rotate between modes of action Tank mix single-site with multi-site fungicides

27 Disease control and resistance management Rotate between modes of action Tank mix single-site with multi-site fungicides Decrease selection pressure Spray less often Weather-based applications Use multisite fungicides or biologicals solo when disease pressure is low Use a recently calibrated sprayer and labeled rates

28 Disease control and resistance management Rotate between modes of action Tank mix single-site with multi-site fungicides Decrease selection pressure Spray less often Weather-based applications Use multisite fungicides or biologicals solo when disease pressure is low Use a recently calibrated sprayer and labeled rates Reduce inoculum Remove senescent foliage, weeds, and overripe fruit from the field

29 Disease control and resistance management Rotate between modes of action Tank mix single-site with multi-site fungicides Decrease selection pressure Spray less often Weather-based applications Use multisite fungicides or biologicals solo when disease pressure is low Use a recently calibrated sprayer and labeled rates Reduce inoculum Remove senescent foliage, weeds, and overripe fruit from the field Make the environment less favorable for gray mold Keep the plants dry

30 Acknowledgements Funding CDFA Specialty Crop Block Grant Program California Strawberry Commission Special Thanks Dr. Guido Schnabel Clemson University ~30 cooperating growers Mark Edsall & Jason Sharrett California Strawberry Commission Sage Finch Pest control advisor Randy Widerburg Pest control advisor Dan Chellemi Driscoll s & Naturipe