Realistic Expectations of Foliar Fungicides for Management of FHB. Scott Henry M.Sc. Seed Treatment & Foliar Fungicide R&D Manager, Bayer CropScience

Transcription

1 Realistic Expectations of Foliar Fungicides for Management of FHB Scott Henry M.Sc. Seed Treatment & Foliar Fungicide R&D Manager, Bayer CropScience

2 Factors that influence FHB fungicide performance (which should influence your expectation) FHB is a very difficult to manage disease 1. Fungicide choice Inherent differences amongst products 2. Crop / Variety choice Fungicide performance differs amongst the different cultivars and even crops 3. Application Quality parameters influencing coverage influence efficacy nozzle choice, configuration, water volume 4. Application Timing narrow window, susceptibility of host and presence of inoculum

3 1. Fungicide Choice Background 3 fungicides commercially available in Canada with label claims for protection against FHB Folicur, Proline and Bravo All 3 product labels essentially claim suppression against FHB a couple more fungicide options may become available in Canada in near future

4 What is suppression? The term suppression is defined by PMRA as consistent control at a level which is not optimal but is still of commercial benefit. The threshold (%) of acceptable disease reduction for this claim depends on the disease and crop, the efficacy of alternative control measures, and the expected impact of a proposed fungicide product on crop yield or quality. Suppression is not used for products which show highly variable performance between trials. A product with low efficacy would require a detailed rationale to demonstrate that the product has value.

5 Public Fungicide Evaluations - USA USWBSI has funded a uniform fungicide test protocol since tests and treatments carried out by various Land Grant Universities Winter, spring wheat and barley evaluated tests annually Uniform treatments (within a given year) and disease / DON ratings 17 fungicides and/or combinations and many rates of these have been evaluated since 1998 Results summarized annually for distribution at USWBSI s National Head Blight Forum

6 Most studies inoculated.

7 Most studies mist-irrigated to encourage disease

8 Efficacy of Folicur 432F based on 66 Uniform Fungicide Trials (USWBSI ) Percent Control Relative to Untreated Rate FHB DON Treatment fl oz Inc Sev Index (ppm) FDK Folicur 3.6F % 22.5% 39.4% 27.4% 39.4% Source: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

9 Multivariate Meta Analysis 10 years of UFTs (> 100 trials) Only SBI (triazoles analyzed) because this group of fungicides has been shown to be most effective Based on % Efficacy (FHB Index Reduction) Prothio (48%), Tebu (40%) and Propi (32%) Based on % DON reduction Prothio (42%), Tebu (23%) and Propi (12%) Source: Lipps et al., Ohio State University, Wooster, OH

10 My Perspective basis more realistic experience?

11 Fusarium Head Blight - % DON Reduction Trial Means Distribution < 5 ppm n=12 >5 ppm n=3 64% 73% Trial Means Grand Means Suppression of mycotoxins with fungicides can reach values higher than 70% Source: BCS R&D - 15 sites (MB) * = NIS included

12 2. Crop / Variety Selection Are better results achieved by spraying a resistant variety? Picture courtesy: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

13 2. Crop / Variety Selection General Fungicide Response in Winter vs Spring Wheat in Uniform Fungicide (USWBSI Trials, 2003) 11 spring and 9 winter wheat trials Percent Control Relative to Untreated FHB DON Treatment Inc Sev Index (ppm) FDK Spring wheat Winter wheat Spring Wheat Advantage environment assumed to be equal due to manipulation (misting) Source: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

14 University of Guelph Ridgetown College modified JD Application Quality

15 University of Guelph Ridgetown College modified JD4210

16 water sensitive paper / simulated wheat head 4 spray passes / sprayer 180 papers for sprayer Size is similar to actual wheat head

17 3. Application Quality Double Swivel TurboFlood Alternating TwinJet Overall C.V. = 37-46% Overall C.V. = 43-75% Overall C.V. = 40-67% Left Front Right Rear Left Front Right Rear Left Front Right Rear

18 3. Application Quality application technique volume of water efficacy (%) efficacy (%) untreated Fungicide Fungicide untreated 46 l/ha 200 l/ha

19 4. Application Timing Effect of Timing of Fungicide Treatment on % Reduction of FHB in Durum Wheat Treatment Folicur Folicur Folicur Folicur Folicur Folicur Greenhouse Trial, 2001 Rate ml / Acre 120 ml 120 ml 120 ml 120 ml 60 ml u 60 ml 60 ml u 60 ml Feekes Growth Stg Applied % heads % heads beg. flower flowering done % Reduction FHB Index Folicur applied with surfactant, forward/backward XR8001 nozzles. ** Inoculation only applied at Feekes (anthesis); range of FHB severities: %. Source: 2001 (NDSU, McMullen et. al.)

20 FHB - % DON Reduction (Barley: Application Timing Trials) Avg UTC DON level = 4.1 ppm BBCH BBCH App B +3-5 Days 130 ml/ac 130 ml/ac 130 ml/ac Source: 4 Trials (BCS R&D - MB) * = NIS included

21 Effect of Fungicide Timing on DON Reduction Wheat 15 Trial# 836 Trial# 837 Deoxynivalenol (ppm) BBCH UTC

22 Influence of Fungicide Application Timing on Fusarium Efficacy If can t spray before, spray as soon as possible after inoculation event % efficacy I - 10 I - 5 inoculation I + 5 I + 10 days treatment : n of days before / after inoculation

23 Making Your Expectations a Reality Integrated approach cultivar selection, rotation and fungicides Fungicides are only one tool Make them as effective as possible with a quality well timed application Result in best success in management of Fusarium Head Blight Increase the probability of your expectations being met