The Effect of Fungicide Treatment for Gray Leaf Spot on Silage-Specific TM Maize Jason Steffl Spring 2009
Background information Home is Redwood Falls, MN Farming system included corn, soybeans, alfalfa, cattle and hogs. Attended college at North Dakota State University. Undergraduate thesis involved potatoes Graduated in 1996 with a B.S. in Agriculture/Biotechnology
Professional Experience Started my career in 1996 as a field technician with Keltgen seeds. Focus was on grain corn Yield trial manager 3 years Nursery and isolations manager 3 years In 1997, Keltgen seeds was purchased by Mycogen Biotech company. In 2000, Mycogen and Cargill companies merged, and became part of DAS.
Professional Experience Product development agronomist 2002 Core crops Early grain and silage corn (<105RM) Alfalfa (all types) Soybeans earlier than group 2.2 soybeans Primary job roles Characterization of experimental products prior to launch. Train commercial/agronomy group on new releases Identify and research new agronomic issues
Fungicides Current products Fungicide Active Ingredient Company Headline Pyraclostrobin BASF Quadris Azoxystrobin Syngenta Quilt Azoxystrobin & Syngenta Propiconazole Stratego Trifloxystrobin & Bayer CropSciences Propiconazole PropiMax EC Propiconazole Dow AgroSciences Tilt Propiconazole Syngenta
Fungicide use and results Positive response to fungicide treatment in high-value crops including corn seed production. Grain corn production 2007 Iowa study Positive yield response to fungicide treatment was observed 77%. Only 27% of the time resulted in a profitable response 2008 University of WI study Only one location out of eleven showed a positive response (6.4bu/a). Though, it still didn t cover the application costs.
Gray Leaf Spot - Introduction GLS is caused by Cercospora zeae-maydis First identified from samples collected from Tehon and Daniels in 1924 in southern IL. Sporadic outbreaks between 1924 and 1980 s in TN, KY, VA, and NC. Government-made disease Federal incentives for reduced tillage practices
Gray Leaf Spot - Identification Early development of gray leaf spot lesion on maize (Ward, 1999).
Gray Leaf Spot - Identification Mature gray leaf spot lesions on maize with the unique rectangular shape (Munkvold, 1999).
Disease cycle of gray leaf spot in maize (Ward, 1999).
Conditions for GLS development Hybrid susceptibility/tolerance Hybrid maturity Planting date Previous crop and tillage practices >35% corn residue have higher risks Environmental conditions Temperatures between 77 86 degrees F Relative humidity >95% Frequent precipitation and/or irrigation
Molds Molds continue to be an issue Molds are the source of dangerous mold poisons (mycotoxins). FDA estimates 1.4 billion dollars lost to the livestock producer Forage improvement, livestock production, and death losses. Forage with high amounts of mold is less palatable resulting in reduced intake of energy, dry matter, and nutrients.
Mold type and mycotoxin production MOLD IDENTIFICATION Mold Color Toxin Produced Comments Penicillium Aspergillus Fusarium Mucor Rhizopus Green to green blue Yellowgreen White to pinkishwhite White/ gray Black/ white Ochratoxin, Citrinin, Patulin Aflatoxin, Ochratoxin Zearalenone, Vomitoxin (DON), T-2 toxin, Fumonism None None Several potential toxins associated with certain species. Most common toxin producer in silage. Found in drought, heat-stressed conditions or insect infested fields. Common in cold, wet season. Certain strains produce extremely potent toxins. Found especially in sealed corn. Grows at low temperatures. Also found in manures and soils. Requires high moisture and an advanced decay mold. Common bread mold. Cladosporium White None Produces yeast like symptoms. Grows at low temperatures.
Objectives Primary The effect of fungicide treatments Quantity (tons per acre) Quality (milk per ton) Profitability Compare two different classes of fungicides Propiconazole Pyraclostrobin Compare two different hybrid types Brown Mid-Rib (BMR) Non-BMR
Objectives - continue Secondary Effects of fungicide treatments Mold concentrations in harvested silage prior to storage and fermentation processes
2008 Locations Location Date Planted Date Harvested Drainage Irrigated Previous Crop Primary Tillage Davenport, IA 5/9/2008 9/22/2008 Fair No Soybean Conventional Macomb, IL 5/2/2008 Viola, IL 5/5/2008 9/10/2008 Fair No Soybean Minimum-Till Janesville, WI 5/5/2008 9/17/2008 Good No Soybean Conventional Mt. Vernon, IN 5/6/2008 9/26/2008 Good No Wheat Conventional Juniata, NE 5/13/2008 9/10/2008 Good Overhead Soybean Minimum-Till Plymouth, NE 5/5/2008 9/3/2008 Good Furrow Soybean Conventional York, NE 4/28/2008 9/9/2008 Good Overhead Soybean Minimum-Till Fowler, IN 4/28/2008 9/9/2008 Fair No Soybean Minimum-Till Mount Joy, PA 5/2/2008 8/27/2008 Fair No Soybean Conventional
Almaco air planter
Experimental plot design 20 19 Non-BMR 18 Rep 2 17 Fungicide 16 Treatment 15 Untreated Check 14 Propiconazole BMR 13 Pyraclostrobin Rep 2 R 12 Untreated Buffer A 11 N 10 G 9 E 8 7 6 5 4 3 2 1 1 2 3 4 5 Plot Non-BMR Rep 1 BMR Rep 1
Hybrids Hybrid Hybrid Type Trait Relative Maturity (days) GLS Tolerance Rating F2F610 BMR NT 108 4 F2F699 BMR HXXT 109 4 F2F635 BMR HXI/RR 110 5 F2F725 BMR HXRW 113 6 F2F797 BMR NT 115 4 2P719 Non-BMR HXXT 110 8 2W726 Non-BMR HXXT 111 8 2Q733 Non-BMR HXXT 113 8 2Q759 Non-BMR HXXT/RR 113 8 2T789 Non-BMR HXXT/RR 114 6
Brown Mid-Rib Hybrids BMR hybrids have reduced lignin formation in the stalks, leaves, and leaf sheaths. Lignin restricts fiber degradation by rumen microbes. Moderately susceptible to fungal pathogens including GLS
2007 GLS control (PA) % leaf damaged GLS % damage 40% 35% 30% 25% 20% 15% 10% 5% 0% F2F610 F2F633 F2F725 F2F682 F27737 F2F797 TMF2Q759 TMF2P719 TMF2Q733 2T789 UNTREATED PROPIMAX + HEADLINE Hybrid
2007 GLS control (DE) 35% 30% 25% 20% 15% 10% 5% 0% UNTREATED TREATED F2F797 F2F721 F2F699 F2F633 F2F631 F2F610 F2F566 F2F485 F2F444 TMF2N422 TMF2N494 TMF94 TMF2Q731 TMF2Q716 TMF2N804 TMF2Q753 T27704 2T801
Fungicide rates and timing Fungicide Common Name Rate/acre (fl. oz/ac) Rate (g a.i./ac) Growth stage PropiMax propiconazole 4 52 VT R1 Headline pyraclostrobin 6 44 VT R1 CO 2 backpack sprayer Travel speed 2.2 mph Volume 17 gpa Pressure 35 psi
Disease Ratings Disease severity was recorded within 7 days of harvest. Percent of diseased leaf tissue from the ear leaf and the leaf above the ear from 10 random plants.
GLS disease rating scale
Harvesting
Sampling Process
Silage sample analysis Near Infrared (NIR) reported values DNDF digestible neutral detergent fiber ADF acid detergent fiber NDF neutral detergent fiber CHO Carbohydrates CP Core Protein Milk 2006 Incorporates analysis values into a simple result expressed in Milk per ton DM. Milk 2006 report.xls
Data Analysis JuMP 7 Analysis of variance Student t-tests Monte Carlo simulation software Probability of economic return based on both treatments and hybrid types. Utilizes the data set from the trial and randomly generates possible outcomes based on input values and model. Two different scenarios were used
Monte Carlo Scenarios Scenario 1 ($/acre, based on silage tons/acre) Primary customer is a contract silage producer D = (Y x R) - C Y (yield difference) = Y (treated) - Y (untreated) R (price of silage) = Price range of $25.00/ton - $35.00/ton C (cost of fungicide treatment) For propiconazole, C = $16.50/acre = ($9.50/ac fungicide cost + $7.00/ac application) For pyraclostrobin, C = $21.00/acre = ($14.00/ac fungicide cost + $7.00/ac application)
Monte Carlo Scenarios Scenario 2 ($/acre, based on Milk per acre) Primary customer is the dairy producer N = (M x P) - C M (milk difference) = M (treated) - M (untreated) P (Price of milk) = Price range of $0.12 - $0.18/lb C (Cost of fungicide treatment) For propiconazole, C = $16.50/acre = ($9.50/ac fungicide cost + $7.00/ac application) For pyraclostrobin, C = $21.00/acre = ($14.00/ac fungicide cost + $7.00/ac application)
Disease Rating Results
Mean disease comparison verses the treatments BMR hybrids Treatment Mean Disease Rating (%) untreated Propiconazole Pyraclostrobin 7.36 A 3.59 B 3.29 B Non-BMR hybrids Treatment untreated Propiconazole Pyraclostrobin Mean Disease Rating (%) 2.03 A 1.50 B 1.38 B
Mean disease percentages by treatment and location across hybrids.
Mean silage yield comparison across locations by hybrid type Yield comparison between treatments by hybrid type Treatment Hybrid Type Silage yield (tons per acre) Pyraclostrobin BMR 29.4 A Untreated BMR 28.8 A Propiconazole BMR 27.9 B Untreated Non-BMR 32.6 A Pyraclostrobin Non-BMR 32.6 A Propiconazole Non-BMR 31.4 B
Yield comparisons between locations Pyraclostrobin for BMR hybrids Showed a positive yield response at 7 out of the 8 locations Significant positive response at Davenport, IA Propiconazole Showed a negative yield response at 6 out of the 8 locations. Significant negative response at Janesville, WI BMR Silage Yield comparison between treatments by location.xls
Yield comparisons between locations Pyraclostrobin for non-bmr hybrids Positive response at 4 out of the 8 locations. Significant at Davenport, IA and Juniata, NE Negative response at 4 out of the 8 locations. Significant at Janesville, WI and York, NE. Propiconazole Positive response at 2 out of the 8 locations. No significant advantage observed Negative response at remaining 6 locations. Significant at Janesville, WI, Juniata, NE, and Viola, IL non-bmr Silage Yield comparison between treatments by location.xls
Yield comparisons between treatments by BMR hybrid Hybrid Type Treatment F2F610 BMR Untreated 29.3 a Net Return ($/acre) Silage Yield (ton per ac) $25.00/ton $30.00/ton $35.00/ton F2F610 BMR Pyraclostrobin 30.7 a 14.00 21.00 28.00 F2F610 BMR Propiconazole 29.5 a -11.50-10.50-9.50 F2F635 BMR Untreated 28 ab F2F635 BMR Pyraclostrobin 28.7 a -3.50 0.00 3.50 F2F635 BMR Propiconazole 26.9 b -44.00-49.50-55.00 F2F699 BMR Untreated 27.2 b F2F699 BMR Pyraclostrobin 29.1 a 26.50 36.00 45.50 F2F699 BMR Propiconazole 27.4 b -11.50-10.50-9.50 F2F725 BMR Untreated 28.4 a F2F725 BMR Pyraclostrobin 28.6 a -16.00-15.00-14.00 F2F725 BMR Propiconazole 27.2 a -46.50-52.50-58.50 F2F797 BMR Untreated 30.6 a F2F797 BMR Pyraclostrobin 29.9 ab -38.50-42.00-45.50 F2F797 BMR Propiconazole 28.4 b -71.50-82.50-93.50
Yield comparisons between treatments by BMR hybrid Hybrid Type Treatment F2F610 BMR Untreated 29.3 a Net Return ($/acre) Silage Yield (ton per ac) $25.00/ton $30.00/ton $35.00/ton Net Return ($/acre) = (Y x R) C Y = Yield different between treated and untreated R = Price of silage C = Cost of fungicide and application Propiconazole = $16.50 Pyraclostrobin = $21.00 F2F610 BMR Pyraclostrobin 30.7 a 14.00 21.00 28.00 F2F610 BMR Propiconazole 29.5 a -11.50-10.50-9.50 F2F635 BMR Untreated 28 ab F2F635 BMR Pyraclostrobin 28.7 a -3.50 0.00 3.50 F2F635 BMR Propiconazole 26.9 b -44.00-49.50-55.00 F2F699 BMR Untreated 27.2 b F2F699 BMR Pyraclostrobin 29.1 a 26.50 36.00 45.50 F2F699 BMR Propiconazole 27.4 b -11.50-10.50-9.50 F2F725 BMR Untreated 28.4 a F2F725 BMR Pyraclostrobin 28.6 a -16.00-15.00-14.00 F2F725 BMR Propiconazole 27.2 a -46.50-52.50-58.50 F2F797 BMR Untreated 30.6 a F2F797 BMR Pyraclostrobin 29.9 ab -38.50-42.00-45.50 F2F797 BMR Propiconazole 28.4 b -71.50-82.50-93.50
Yield comparisons between treatments by BMR hybrid Hybrid Type Treatment F2F610 BMR Untreated 29.3 a Net Return ($/acre) Silage Yield (ton per ac) $25.00/ton $30.00/ton $35.00/ton F2F610 BMR Pyraclostrobin 30.7 a 14.00 21.00 28.00 F2F610 BMR Propiconazole 29.5 a -11.50-10.50-9.50 F2F635 BMR Untreated 28 ab F2F635 BMR Pyraclostrobin 28.7 a -3.50 0.00 3.50 F2F635 BMR Propiconazole 26.9 b -44.00-49.50-55.00 F2F699 BMR Untreated 27.2 b F2F699 BMR Pyraclostrobin 29.1 a 26.50 36.00 45.50 F2F699 BMR Propiconazole 27.4 b -11.50-10.50-9.50 F2F725 BMR Untreated 28.4 a F2F725 BMR Pyraclostrobin 28.6 a -16.00-15.00-14.00 F2F725 BMR Propiconazole 27.2 a -46.50-52.50-58.50 F2F797 BMR Untreated 30.6 a F2F797 BMR Pyraclostrobin 29.9 ab -38.50-42.00-45.50 F2F797 BMR Propiconazole 28.4 b -71.50-82.50-93.50
Yield comparisons between treatments by non-bmr hybrid Hybrid Type Treatment 2P719 Non-BMR Untreated 31.1 ab Net Return ($/acre) Silage yield (ton per acre) $25.00/ton $30.00/ton $35.00/ton 2P719 Non-BMR Pyraclostrobin 31.9 a -1.31 2.63 6.56 2P719 Non-BMR Propiconazole 30.2 b -40.98-45.88-50.78 2Q733 Non-BMR Untreated 33.6 a 2Q733 Non-BMR Pyraclostrobin 32.8 ab -41.95-46.14-50.33 2Q733 Non-BMR Propiconazole 32.0 b -56.02-63.92-71.82 2Q759 Non-BMR Untreated 32.4 a 2Q759 Non-BMR Pyraclostrobin 32.5 a -19.66-19.39-19.12 2Q759 Non-BMR Propiconazole 31.8 a -32.84-36.11-39.38 2T789 Non-BMR Untreated 32.2 a 2T789 Non-BMR Pyraclostrobin 32.4 a -15.27-14.12-12.97 2T789 Non-BMR Propiconazole 32.3 a -13.45-12.84-12.23 2W726 Non-BMR Untreated 33.8 a 2W726 Non-BMR Pyraclostrobin 33.3 a -32.63-34.95-37.28 2W726 Non-BMR Propiconazole 31.0 b -86.75-100.8-114.85
Predicted milk yield between treatments by hybrid type. Treatment Type Milk yield (milk per ton DM) Pyraclostrobin BMR 3252.5 A Propiconazole BMR 3234.7 A Untreated BMR 3231.4 A Pyraclostrobin Non-BMR 3076.3 A Propiconazole Non-BMR 3073.1 A Untreated Non-BMR 3069.3 A
Probability analysis scenario 1
Probability analysis scenario 2
Probability analysis - Summary Fungicide Hybrid Type Based on Silage yield difference (tons/acre) Economic loss (P<$0/ac) Economic gain (P>$0/ac) Based on Milk yield difference (milk/acre) Economic loss (P<$0/ac) Economic gain (P>$0/ac) Propiconazole BMR 69% 31% 65% 35% Propiconazole Non-BMR 74% 26% 68% 32% Pyraclostrobin BMR 44% 56% 32% 68% Pyraclostrobin Non-BMR 55% 45% 46% 54%
Mold results Results showed a wide range of values with a large degree of variability. The mean mold counts between treatment were not significantly different. No observed significant difference of mold counts among the different treatments for each hybrid, except for F2F797 at Mt. Vernon. York, NE had the highest mean for mold counts.
Mold type and concentration by treatment across all hybrids.
Conclusion GLS disease pressure Location characteristics do not support high risk of infection. Soybean or wheat rotation Some form of tillage reducing any remaining corn residue. Speculate that the infection reported in 2009 was from secondary sources (fields)
Conclusion - continue Predicting success of fungicide applications. Pre-plant observations Hybrid susceptibility Hybrid maturity and/or planting date Corn crop residue and tillage practices History of the location Observations prior to fungicide application Presence and severity of diseases present Weather outlook
Conclusion continue Differences in management of silage production Harvest date of silage (R5) is typically >15 days prior to grain harvest. Less time available for GLS to compromise stalk quality and standability. Harvest of the whole plant reduces the amount of residue on the soil. The majority of residue left is the 8-10 inches of the bottom stalk.
Future research Repeat of fungicide study with emphasis on the BMR hybrids only. Reduce entries Increase reps to four per location Focus testing efforts on high risk areas Additional research to investigate the potential for silage yield suppression observed from the application of propiconazole.
Acknowledgements Mary Wiedenhoeft Tim Yelk and Trent Lindenman DAS Field R&D staff Rhee Holley Tom Kwolek Karl Schnelle David Taysom Jesse Drew
Questions