Fusarium Head Blight (FHB, Scab) Epidemic Risk Forecasting System
Minnesota’s State System
Management of FHB includes an integrated approach such as growing cultivars with resistance, applying fungicide at the early flowering growth stage, and managing infested crop residue with rotation and/or tillage. Epidemic risk predictions of FHB are used as decision aids to determine whether a fungicide application should be made to protect the crop. Since 2004, a statewide FHB epidemic risk forecasting system has been operational and free of charge at http://mawg.cropdisease.com.
The Minnesota FHB epidemic risk forecasting system website is funded by the Minnesota Wheat Research and Promotion Council, and maintained by Meridian Environmental Technology, Inc. (Meridian) in cooperation with the University of Minnesota. Meridian maintains a comprehensive weather database that integrates data collected from surface-observed stations and remotely-sensed information from weather radars and satellites. Observed weather conditions throughout Minnesota are recorded by federal and state agencies such as the National Weather Service and the Federal Aviation Administration (>82 stations), the Minnesota Department of Transportation, Road Weather Information System (93 stations), and the North Dakota Agricultural Weather Network (NDAWN; 10 stations). Remotely-sensed information originates from six NEXt Generation Weather RADar (NEXRAD) weather radars. The outcome is a 4-km resolution composite of hourly precipitation, temperature, and humidity data which is used to update the forecasting system every three hours for a total of eight times a day.
During 2004, five on-farm disease management experiments were conducted within commercial production fields located from north to south in the Red River Valley (near Kittson, Strathcona, Oklee, Perley, and Fergus Falls). During 2005, experiments were again planted at similar locations (near Kittson, Strathcona, Oklee, Perley, and Rothsay). Unfortunately, stand losses due to severe weather and flooding resulted in tests at the Kittson and Strathcona locations being discontinued. During 2006 and 2007, tests were planted near Oklee and Fergus Falls while in 2008 trials were established near Fisher and St. Hilaire. In total, from 2004 to 2008, disease severity from 25 environments (location + variety flowering period) was tracked and ground-truth data were collected from replicated, small-plot experiments consisting of data from five to 15 wheat varieties.
During 2004, the FHB risk forecasting model predicted an elevated (moderate to high) risk that an FHB epidemic would occur in two of the five environments, but none were observed. During 2005, it predicted an elevated epidemic risk in one of six environments. An epidemic occurred at that location, as well as at another location where the system predicted a low risk for an epidemic. During 2006-2008, the model predicted low risks in all environments, and no epidemics were observed.
During the last five years, Minnesota’s forecasting system has been incorrect three out of 25 situations. It predicted two epidemics which didn’t occur, and failed to predict one that did.
back to the top # # #
National Forecasting System
Deployed since 2004, the national FHB epidemic risk forecasting system website located at http://www.wheatscab.psu.edu is supported by the U.S. Wheat and Barley Scab Initiative. The system services the central and eastern U.S. wheat community located in 24 states, including Minnesota. A number of weather data sources are used by the national model system, with the most substantial data contributions provided by federal agencies. The national epidemic risk forecasting system relies primarily on remote-sensed weather data devices (e.g.: radar, satellites), whereas the Minnesota relies primarily on observed station data. A disease forecasting component based on 24 hour and 48 hour weather forecasts was added to the national model in during 2006. The Minnesota system also incorporated disease forecasts into its risk forecasting website during 2008.
Minnesota Scab Epidemic Risk Forecasting System
Each growing season, a colored-coded state map is displayed that shows FHB epidemic risk level differences at a glance (Fig. A). Dark green coloring indicates low risk, yellow indicates moderate risk, and dark red indicates high risk that a scab epidemic could occur.
Plant pathologist commentary. This is feature has been active for a couple of years and is meant to help with map interpretation by adding on-the-ground information from a plant pathologist’s perspective. Found just below the colored map of Minnesota (Fig. B), commentary contains observed disease and field information with additional tidbits to consider during the growing season. The text is updated frequently during the summer.
Glenn ≠ Oxen. Since 2006, the spring wheat epidemic risk forecasting model has included an additional equation term representing FHB resistance levels of cultivars. Using a drop-down menu located on the home page, users have the option of selecting either a specific variety of interest, or a generic FHB resistance level (very susceptible, susceptible, moderately susceptible, moderately resistant). This model modification allows for a more precise prediction since specific variables such as location-specific weather and variety response to FHB are known. It is likely that incorporating FHB resistance levels of varieties into the model may be one of the most beneficial modifications made in recent years.
Growth Stage Estimator. To estimate the growth progress of your crop, select the “Wheat Growth Model” and a different state map will be displayed. Click on an approximated location for the field of interest and type in the needed information (variety, date planted, seeding depth), then select the “GO” button. An estimate of the crop growth stages will be displayed. This estimate is based on growing degree days for wheat and is calculated using observed weather conditions. As the number of weather data increase, the estimate will be more and more accurate. For example, an estimate of the early flowering date made at the 2-leaf stage is less accurate than when it is made at the sixth leaf stage. This estimator has proven to be reliably accurate.
Additional features. Leaf disease severity estimators for tan spot, Septoria, and leaf rust. Weather conditions and extension bulletins can also be accessed from the left side of the home page.
| Fig A. |
Fig B. |
 |
 |
back to the top # # #
Understanding Practical Outcomes from Implementing Integrated Fusarium head blight (FHB, scab) Management Strategies on Malting Barley in Minnesota
Authors:
Charla Hollingsworth, Extension plant pathologist, Chris Motteberg, Plant pathology scientist and Linnea Skoglund, Plant pathologist (formerly of Busch Agricultural Resources, Inc. (BARI))
The objective of this two year experiment was to determine grain yield and kernel quality benefits from treating four commercially-available 6-rowed malting barley cultivars and four advanced 6-rowed malting germplasm lines with different fungicide-based disease management strategies to manage Fusarium head blight (FHB). Specifically, lines in the test represent germplasm with increased resistance to FHB compared with present varieties. Placing the test in a commercial field environment allowed us to determine whether genetic resistance would support increased disease management after a “second generation” fungicide (Prosaro) was used. If sufficient management of FHB could be achieved, successful malt barley production might once again be possible in the Red River Valley.
The 2007 experiment was planted into soybean residue at a test location near Warren, MN. Four commercially-available varieties (Drummond, Legacy, Robust, and Tradition) were planted as well as four barley germplasm entries (Celebration and 6B01-2513 (BARI), M122 (University of Minnesota), and ND20448 (North Dakota State University). All entries were exposed to a fungicide treatment (Table 1) at an early heading crop growth stage. Likewise, the 2008 experiment tested the same varieties and germplasm entries as before with the same fungicide treatments. Test locations were in commercial field sites near Warren and Mahnomen, MN. Data from the three experiment years were analyzed together with one exception. Deoxynivalenol (DON) levels in grain developed sufficiently at only one of the three sites. DON data from the Mahnomen-08 test location were analyzed singly.
Table 1. FHB disease management strategies tested on eight 6-rowed malting barley at a total of three locations during 2007-08.
|
Trt |
Fungicide product |
Active ingredient |
Application Rate* |
|
1 |
Nontreated control…………… |
- - - |
|
|
2 |
Folicur………………………... |
tebuconazole |
4.0 fl oz/A |
|
3 |
Prosaro………………………... |
tebuconazole & prothioconazole |
6.5 fl oz/A |
|
4 |
Prosaro………………………... |
tebuconazole & prothioconazole |
8.2 fl oz/A |
*Treatments 2 through 4 included 0.125% Induce, a nonionic surfactant. Fungicide applications were made at early heading.
Disease Management
FHB disease development and associated losses were minimal at our test sites. Disease incidence was significantly less for germplasm entries compared with varieties (P=0.0096), but differences weren’t detected for FHB severity. Similarly, FHB index (= severity x incidence / 100) was higher for variety than germplasm whether fungicide was applied or not. Fungicide application had no effect on yield with one exception. Varieties responded to a Folicur application (strategy 2) resulting in an increase of 5.81 bu/A (P=0.0279) over the germplasm entries. During 2008, DON means ranged from 0.21 to 1.26 ppm at the Mahnomen site. The three germplasm entries (Celebration, ND20448, and M122) had the lowest DON levels, while Legacy had the highest. From this single site, single year data set, the no fungicide control and Folicur treatments were less effective at reducing DON than either Prosaro treatment. When fungicide treatment and entry were analyzed together, however, the Prosaro treatments didn’t significantly reduce DON levels in Celebration, ND20448, or M122 when compared with the no fungicide or Folicur treatments indicating that resistance level, rather than fungicide application, is key in managing the toxin.
Overview
Breeding for FHB resistance in barley is an ongoing effort. Using an integrated disease management approach that includes disease resistance, fungicide application, and rotation was investigated in this two-year research effort. Our results indicate that varietal resistance, rather than fungicide treatment, is most critical for managing FHB. While fungicides appear to benefit barley production in general, the effects were often not statistically significant in low disease years.
Acknowledgements
This research project was funded, in part, by Busch Agricultural Resources, Inc. and the U.S. Wheat & Barley Scab Initiative. It was supported by NDSU, UM, Bayer CropScience, and the UM Mycotoxin lab. The authors appreciate the support from grower cooperators Dwight and Cindy Anderson (Warren, MN), and Kelly and Perry Skaurud of Skaurud Grain Farms (Gary, MN).
This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0790-8-070. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.
back to the top # # #
2008 Red River Valley On-Farm Disease Management Trials
Authors: Charla Hollingsworth, Extension plant pathologist, Chris Motteberg, Plant pathology scientist, and Steve Ross, Manager of Ross Seed Co.
During 2008, data were collected from two on-farm locations located near Fisher and St. Hilaire, MN. Both sites represented a collaborative research effort with Ross Seed Co. Small, replicated plots of spring wheat were planted into fields with soybean residue. Fifteen wheat varieties were tested for their responses to six fungicide treatments while an additional 15 varieties/germplasm lines were exposed to two fungicide treatments. Yield and quality responses were determined. Economic analyses for each variety/entry were calculated from representative grain sub-samples that were based on test weight and protein data. For reporting purposes, fictitious grain sales were made based on harvest results to determine the estimated revenue generated from each variety and disease management treatment combination. The sales occurred on 2 October 2008. Deoxynivalenol (DON or vom) levels were either non-detectable (less than 0.05 ppm) or below the 2.0 ppm target threshold so toxin discounts did not apply.
Disease Summary
Tan spot was not a production issue during 2008, and leaf rust established later than normal, causing little if any trouble. However, epidemics of bacterial stripe and black chaff were observed across the Valley. These bacterial diseases were associated with substantial losses at some locations. This comes only three years since our last bacterial stripe epidemic in 2005. Plants showing symptoms of wheat streak mosaic virus, a mite vectored disease, were widespread across the Valley, but incidence was low. Overall prevalence of Fusarium head blight (FHB, scab) was low, but several localized epidemics were reported from the north and central areas of the Valley.
Weather conditions were variable across locations. Scattered thundershowers, rather than large weather systems provided localized precipitation as well as severe wind or tornadoes. The Fisher test site had little precipitation, but plants managed to produce excellent yields in spite of this challenge. The St. Hilaire site had timely and sufficient rains which supported thick, lush plant canopies and incredible yields. This environment promoted powdery mildew development which was moderately severe on Hat Trick, a susceptible variety.
Disease Management Treatments
When averaged over both locations yield responses ranged from Glenn (78.1 bu/A) to Faller (107.8 bu/A), while test weights ranged from 62.7 lb/bu (Samson) to 65.9 lb/bu (Glenn) (Table 2A). Kuntz had the lowest protein (12.7%) while Glenn (14.9%) had the highest. Consequently, Kuntz had the largest protein discount of the varieties tested (-$0.56/bu). Low quality contributed to substantial discounts in several of the experimental germplasm entries tested (Table 2B).
Overview
Varieties responded well to this year’s growing environment, producing excellent yields of high quality grain. An grouped analysis of varieties by FHB-resistance level ( susceptible, moderately susceptible, moderately resistant) from the last two years (2007-08) indicates that scheduled growth stage applications of one or more fungicides during low disease years did not significantly increase yield, quality, or net return of varieties in any FHB-resistance level.
Acknowledgements
This project was funded, in part, by the U.S. Wheat and Barley Scab Initiative, WestBred, and AgriPro. It was supported by Ross Seed Co., Dr. Yanhong Dong, Univ. of Minnesota Mycotoxin Laboratory, BASF, Bayer CropScience, and Syngenta Crop Protection.
This material is based upon work supported by the U.S. Department of Agriculture, under Agreement No. 59-0790-8-070. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.
Table 1. Disease management strategies tested during 2008 at two test locations in the Red River Valley.
|
|
|
|
Application |
|
|
Product |
Active ingredient |
Rate* |
Timing |
|
1 |
Nontreated control…. |
-- |
-- |
-- |
|
2 |
Dividend Extreme….. |
difenoconazole and mefenoxam |
3 fl. oz./100 lbs. |
seed applied |
|
3 |
Headline.....................
Folicur/Proline........... |
pyraclostrobin
tebuconazole & prothioconazole |
3 fl. oz./a
3 + 3 fl. oz./a |
4-5 leaf
early flower |
|
4 |
Dividend Extreme…..
Headline.....................
Folicur/Proline........... |
difenoconazole & mefenoxam
pyraclostrobin
tebuconazole/prothioconazole |
3 fl. oz./100 lbs.
3 fl. oz./a
3 + 3 fl. oz./a |
seed applied
4-5 leaf
early flower |
|
5 |
Dividend Extreme…..
Folicur/Proline........... |
difenoconazole & mefenoxam
tebuconazole & prothioconazole |
3 fl. oz./100 lbs.
3 + 3 fl. oz./a |
seed applied
early flower |
|
6 |
Folicur/Proline........... |
tebuconazole & prothioconazole |
3 + 3 fl. oz./a |
early flower |
*Treatments 3 through 6 included 0.125% Induce, a nonionic surfactant.
Table 2A. Varietal responses to disease management strategies at Fisher and St. Hilaire, MN.
|
Variety |
Trtmt timing 1 |
Yield
(bu/A) |
Test Wt
(lb/bu) |
Protein
(%) |
Premium/ Discount 2 ($/bu) |
Cash price
($/bu) |
Fungicide + appl. cost 3 ($/A) |
Estimated Return ($/A) |
|
Ada |
F |
98.6 |
65.6 |
13.9 |
-0.08 |
6.58 |
17.23 |
$631.56 |
|
U of M |
L, F |
99.8 |
64.5 |
13.7 |
-0.16 |
6.50 |
23.55 |
$625.15 |
|
|
None |
93.2 |
65.1 |
13.7 |
-0.16 |
6.50 |
0.00 |
$605.80 |
|
|
S, L, F |
94.4 |
64.4 |
13.8 |
-0.08 |
6.58 |
26.98 |
$594.17 |
|
|
S |
90.3 |
64.1 |
13.9 |
-0.08 |
6.58 |
3.43 |
$590.74 |
|
|
S, F |
91.8 |
65.2 |
14.0 |
0.00 |
6.66 |
20.66 |
$590.73 |
|
Mean |
94.7 |
64.8 |
13.8 |
-0.09 |
6.57 |
15.31 |
$606.36 |
|
Alsen |
None |
89.2 |
64.6 |
14.8 |
0.00 |
6.66 |
0.00 |
$594.07 |
|
NDSU |
S, L, F |
90.7 |
64.3 |
14.4 |
0.00 |
6.66 |
26.98 |
$577.08 |
|
|
F |
88.8 |
63.8 |
14.4 |
0.00 |
6.66 |
17.23 |
$574.18 |
|
|
S, F |
88.4 |
64.1 |
14.4 |
0.00 |
6.66 |
20.66 |
$568.08 |
|
|
L, F |
87.8 |
64.4 |
14.2 |
0.00 |
6.66 |
23.55 |
$561.20 |
|
|
S |
84.4 |
64.4 |
14.6 |
0.00 |
6.66 |
3.43 |
$558.67 |
|
Mean |
88.2 |
64.3 |
14.5 |
0.00 |
6.66 |
15.31 |
$572.21 |
|
Bigg Red |
None |
93.8 |
65.8 |
14.0 |
0.00 |
6.66 |
0.00 |
$624.71 |
|
WestBred |
S |
93.9 |
64.9 |
13.9 |
-0.08 |
6.58 |
3.43 |
$614.43 |
|
|
S, F |
96.5 |
65.6 |
13.7 |
-0.16 |
6.50 |
20.66 |
$606.59 |
|
|
S, L, F |
96.2 |
65.1 |
13.9 |
-0.08 |
6.58 |
26.98 |
$606.02 |
|
|
L, F |
93.1 |
64.6 |
13.8 |
-0.08 |
6.58 |
23.55 |
$589.05 |
|
|
F |
92.1 |
65.3 |
13.9 |
-0.08 |
6.58 |
17.23 |
$588.79 |
|
Mean |
94.3 |
65.2 |
13.9 |
-0.08 |
6.58 |
15.31 |
$604.93 |
|
Breaker |
S, F |
94.5 |
64.5 |
14.1 |
0.00 |
6.66 |
20.66 |
$608.71 |
|
WestBred |
F |
93.6 |
64.8 |
13.8 |
-0.08 |
6.58 |
17.23 |
$598.66 |
|
|
S |
90.6 |
64.5 |
13.9 |
-0.00 |
6.58 |
3.43 |
$592.72 |
|
|
None |
88.4 |
65.3 |
14.0 |
0.00 |
6.66 |
0.00 |
$588.74 |
|
|
S, L, F |
90.2 |
64.8 |
13.9 |
-0.08 |
6.58 |
26.98 |
$566.54 |
|
|
L, F |
86.9 |
63.6 |
13.8 |
-0.08 |
6.58 |
23.55 |
$548.25 |
|
Mean |
90.7 |
64.6 |
13.9 |
-0.05 |
6.61 |
15.31 |
$583.94 |
|
Briggs |
S, L, F |
97.2 |
63.9 |
14.4 |
0.00 |
6.66 |
26.98 |
$620.37 |
|
SDSU |
F |
92.3 |
64.0 |
14.6 |
0.00 |
6.66 |
17.23 |
$597.49 |
|
|
S, F |
92.8 |
64.0 |
14.4 |
0.00 |
6.66 |
20.66 |
$597.39 |
|
|
None |
87.9 |
64.3 |
14.4 |
0.00 |
6.66 |
0.00 |
$585.41 |
|
|
S |
88.0 |
64.0 |
14.6 |
0.00 |
6.66 |
3.43 |
$582.65 |
|
|
L, F |
90.5 |
63.8 |
14.4 |
0.00 |
6.66 |
23.55 |
$579.18 |
|
Mean |
91.5 |
64.0 |
14.5 |
0.00 |
6.66 |
15.31 |
$593.75 |
|
Faller |
F |
107.8 |
64.5 |
13.1 |
-0.40 |
6.26 |
17.23 |
$657.60 |
|
NDSU |
None |
99.9 |
64.2 |
13.2 |
-0.32 |
6.34 |
0.00 |
$633.37 |
|
|
S |
101.6 |
63.7 |
13.1 |
-0.40 |
6.26 |
3.43 |
$632.59 |
|
|
S, F |
102.5 |
64.0 |
13.1 |
-0.40 |