Realistic Expectations of Foliar Fungicides for Management of

FHBScott Henry M.Sc.Seed Treatment & Foliar Fungicide R&D Manager, Bayer CropScience

Factors that influence FHB fungicide performance(which should influence your expectation)

1. Fungicide choice– Inherent differences amongst products

2. Crop / Variety choice– Fungicide performance differs amongst the different

cultivars and even crops3. Application Quality

– parameters influencing coverage influence efficacy– nozzle choice, configuration, water volume

4. Application Timing– narrow window, susceptibility of host and presence

of inoculum

FHB is a very difficult to manage disease

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

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.

Public Fungicide Evaluations - USA• USWBSI has funded a uniform fungicide test protocol

since 1998.– tests and treatments carried out by various Land

Grant Universities– Winter, spring wheat and barley evaluated

• 15-25 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

Most studies inoculated.

Most studies mist-irrigated to encourage disease

Efficacy of Folicur 432F based on 66 Uniform Fungicide Trials(USWBSI 1998-2003)

Rate FHB DONTreatment fl oz Inc Sev Index (ppm) FDKFolicur 3.6F 4.0 19.7% 22.5% 39.4% 27.4% 39.4%

Percent Control Relative to Untreated

Source: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

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

My Perspective basis more realistic experience?

Fusarium Head Blight - % DON ReductionTrial Means Distribution

Source: 2003-2008 – BCS R&D - 15 sites (MB)

< 5 ppm – n=12>5 ppm – n=3

Trial Means

Grand Means

73%64%

• Suppression of mycotoxins with fungicides can reach values higher than 70%

* = NIS included

Are better results achieved by spraying a resistant variety?

2. Crop / Variety Selection

Picture courtesy: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

General Fungicide Response in Winter vs Spring Wheat in Uniform Fungicide (USWBSI Trials, 2003)

FHB DONTreatment Inc Sev Index (ppm) FDK

Spring wheat 40.3 49.5 63.3 37.9 41.6

Winter wheat 26.2 22.9 40.4 26.1 28

Spring Wheat Advantage +14.1 +26.6 +22.9 +11.8 +13.6

Percent Control Relative to Untreated

11 spring and 9 winter wheat trials

• environment assumed to be equal due to manipulation (misting)

2. Crop / Variety Selection

Source: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY

3. Application Quality

University of Guelph – Ridgetown College – modified JD4210

University of Guelph – Ridgetown College – modified JD4210

water sensitive paper / simulated wheat head

• 4 spray passes / sprayer• 180 papers for sprayer

Size is similar to actual wheat head

Left Front Right Rear

Overall C.V. = 40-67%

Left Front Right Rear

Overall C.V. = 37-46% Overall C.V. = 43-75%

Left Front Right Rear

2

3

1

TwinJetTurboFlood AlternatingDouble Swivel

3. Application Quality

untreated 46 l/ha 200 l/hauntreated Fungicide Fungicide

application technique volume of water

efficacy (%) efficacy (%)

3. Application Quality

Folicur24.710.54 - flowering done120 ml81.010.51 – beg. flower120 ml

FolicurFolicur

Folicur

81.010.51+10.5460 ml u 60 ml92.310.3+10.5160 ml u 60 ml

% Reduction FHB Index++

Feekes Growth Stg Applied

Rateml / Acre

Treatment

Folicur

75.810.5 - 100% heads120 ml59.110.3 - 50% heads120 mlFolicur

Effect of Timing of Fungicide Treatment on % Reduction of FHB in Durum Wheat

Greenhouse Trial, 2001

Source: 2001 (NDSU, McMullen et. al.)

•Folicur applied with surfactant, forward/backward XR8001 nozzles. ** Inoculation only applied at Feekes 10.51 (anthesis); range of FHB severities: 2.3 - 36.4%.

4. Application Timing

Source: 4 Trials - 2002-2003 (BCS R&D - MB)

Avg UTC DON level = 4.1 ppm

BBCH 57-59 App B +3-5 DaysBBCH 51-53

FHB - % DON Reduction(Barley: Application Timing Trials)

130 ml/ac 130 ml/ac130 ml/ac

* = NIS included

10

5

0

15

Deo

xyni

vale

nol (

ppm

)

Effect of Fungicide Timing on DON ReductionWheat

Trial# 836 Trial# 837

65UTC 53 55 61-6357-59BBCH

0

20

40

60

80

100

% e

ffica

cy

treatment : n° of days before / after inoculationI - 10 I - 5 I + 5 I + 10 daysinoculation

Influence of Fungicide Application Timing on Fusarium Efficacy

If can’t spray before, spray as soon as possible after inoculation event

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