Realistic Expectations of Foliar Fungicides for Management of FHB Scott Henry M.Sc.

Realistic Expectations of Foliar
Fungicides for Management of
FHB
Scott Henry M.Sc.
Seed Treatment & Foliar Fungicide R&D
Manager, Bayer CropScience
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
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)
Percent Control Relative to Untreated
Treatment
Rate
fl oz
Folicur 3.6F 4.0
Inc
FHB
Sev
Index
DON
(ppm)
19.7%
22.5%
39.4%
27.4% 39.4%
Source: Don Hershman, Extension Plant Pathologist, University of Kentucky, Princeton, KY
FDK
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 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: 2003-2008 – BCS R&D - 15 sites (MB)
* = NIS included
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
2. Crop / Variety Selection
General Fungicide Response in Winter vs Spring
Wheat in Uniform Fungicide (USWBSI Trials, 2003)
Percent Control Relative to Untreated
11 spring and 9 winter wheat trials
FHB
DON
Index (ppm) FDK
Treatment
Inc
Sev
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
• environment assumed to be equal due to manipulation (misting)
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
3. Application Quality
Double Swivel
TurboFlood Alternating
TwinJet
1
2
3
Overall C.V. = 37-46%
Left Front Right Rear
Overall C.V. = 43-75%
Overall C.V. = 40-67%
Left Front Right Rear
Left Front Right Rear
3. Application Quality
application technique
efficacy (%)
untreated
Fungicide
volume of water
efficacy (%)
Fungicide
untreated
46 l/ha
200 l/ha
4. Application Timing
Effect of Timing of Fungicide Treatment on %
Reduction of FHB in Durum Wheat
Greenhouse Trial, 2001
Treatment
Rate
Feekes Growth
% Reduction
Stg Applied
FHB Index++
ml / Acre
120 ml
Folicur
10.3 - 50% heads
59.1
Folicur
10.5 - 100% heads
120 ml
75.8
10.51 – beg. flower
Folicur
120 ml
81.0
10.54 - flowering done
Folicur
120 ml
24.7
Folicur
60 ml u 60 ml
10.3+10.51
92.3
•Folicur applied with surfactant, forward/backward XR8001 nozzles.
Folicur only applied
60 mlat uFeekes
60 ml
10.51+10.54
** Inoculation
10.51 (anthesis);
range of FHB severities:81.0
2.3 - 36.4%.
Source: 2001 (NDSU, McMullen et. al.)
FHB - % DON Reduction
(Barley: Application Timing Trials)
BBCH 51-53
130 ml/ac
Source: 4 Trials - 2002-2003 (BCS R&D - MB)
BBCH 57-59
130 ml/ac
Avg UTC DON level = 4.1 ppm
App B +3-5 Days
130 ml/ac
* = NIS included
Effect of Fungicide Timing on DON Reduction
Wheat
Deoxynivalenol (ppm)
15
ΠTrial# 836 ΠTrial# 837
10
5
0
BBCH
UTC
53
55
57-59
61-63
65
Influence of Fungicide Application Timing on
Fusarium Efficacy
If can’t spray before, spray as soon as possible after inoculation event
100
% efficacy
80
60
40
20
0
I - 10
I - 5 inoculation
I+5
I + 10 days
treatment : n° of days before / after inoculation
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