Disease management of row crops ---------------------------------------- Agronomic In-Service Training, NREC Quincy, FL January 17th, 2017 Nicholas S. Dufault Extension Specialist Row Crops & Vegetables Plant Pathology Department/IFAS University of Florida
Disease topics: Cotton & Peanut Cotton Diseases Fungicides available Multi-state trials Assess Risk Peanut Diseases Variability of products Rotating modes of action Cultivar selection Trial Results On-farm results
Do fungicides help control disease and save yields in cotton? Target spot (Corynespora) Includes boll rots Tan centers Stemphylium leaf spot Secondary disease Potassium deficiencies Photo Courtesy of Bob Kemerait
Fungicides for Foliar Diseases of Cotton Headline (pyraclostrobin) (6 fl oz/a) Single application expected Labeled for foliar disease control Twinline (pyraclostrobin + metconazole) (7-8.5 fl oz/a) 2(ee) label for control of leaf spot (Corynespora cassiicola) Quadris (azoxystrobin) (6 or 9 fl oz/a) Supplemental label received in July 2008 Priaxor (fluxapyroxad + pyraclostrobin) (4 to 8 fl oz/a) Corynespora control, release Supplemental label Topguard (flutriafol) (7 to 14 fl oz/a) Corynespora Control Rate still being evaluated Tebuzol 3.6F (tebuconazol) (6-8 fl oz/a) Labeled for control of southwestern cotton rust Puccinia cacabata
Multi-state project with 7 states over 3 years from gulf coast to Virginia Virginia Tennessee Louisiana Mississippi Alabama Georgia Florida 2014 2015 2014-2015 --- 2016
Variety effects on disease
Significant effects of variety were observed on severity across years & locations. 100 Excluding (FL-2014, MS-2015) 80 Severity (%) 60 40 20 0 DP1137 Phyt. 499
Variety also had a significant effect on defoliation across years & locations. 100 Excluding (VA-2014, FL-2014, MS-2015) Defoliation (%) 80 60 40 20 0 DP1137 Phyt. 499
There were occasions when DP1137 had slight more or similar defoliation to PHY499 70 PHY499 DP1137 60 Percent (%) Defoliation 50 40 30 20 GA-1 in 2016 is an example. 10 0 FL GA-1 GA-2 AL MS LA-1 LA-2 TN
How did fungicides effect disease and yields?
In general, all fungicide treatments reduced defoliation. Priaxor results on Phytogen 499
However, this results was less apparent on DP1137. Priaxor results on Delta & Pine Land 1137
Only, Headline and Priaxor applications lead to significant yield increases. This effect was more apparent on Phytogen 499. Yield increases were about 5 to 6% on average.
Is a 6% yield increase enough? If you produce 2 bales of cotton per acre: that is ~60 lb increase per acre at 75 cents that is $45 per acre gain fungicide cost alone is $26.24 per acre Returns on fungicide are minimal CottonUS.org
Target spot can be a problem! Corynespora target spot onset and severity varied among locations throughout the southeast Disease varied between cultivars, indicating cultivar is important. Fungicides can reduce defoliation, especially in certain cultivars (i.e. Phytogen499) Fungicides can save yields (1 to 10%), but it depends of cultivar and year/environment.
No matter what, it is critical to assess the risk of disease first (Scout!) http://www.ugacotton.com/vault/file/2015-uga-cotton-production- Guide.pdf https://sites.aces.edu/group/timelyinfo/documents/2015%20tar get%20spot%20control%20options%20timely%20information.p df
Peanut disease management
Products vary in their disease control Leaf spot individual product trials Group 3 (Tebuconazole, Propiconazole, Alto) Group 11 (Azoxystrobin and Pyraclostrobin) Group 7 (Penthiopyrad) Planting date: after 6/1 Variety: Georgia-06G
Specific chemistries control specific leaf spot pathogens. Disease Incidence (%) 100 90 80 70 60 50 40 30 20 10 0 ELS LLS Rust Untreated Chloro. Only Teb. Only Azoxy. Only Pyrac. Only 2014 Citra Data
It appears region was also important for overall disease control. 200 Citra (ELS) Marianna (LLS) Quincy (Rust) 175 150 Percent (%) Yield Increase 125 100 75 50 25 0-25 Chlor. Teb. Azoxy. Pyrac. Prop. 2015 Yield Data
Group 11s do not do well when early leaf spot (58% of disease) is predominate. Percent (%) Yield Increase 500 450 400 350 300 250 200 150 100 50 0 Chloro. Teb. Azxoy. Pyrac. Prop. Alto Fontelis 2016 Citra Data
Group 3s had less control when LLS was predominate. 1 NTC 2 Chloro. 3 Teb. 4 Azoxy. 5 Pyrac. 6 Prop. 7 Chloro/Prop 8 Teb/Chloro 9 Alto. 10 Fontelis 2016 Jay Data
Based on the 2014-16 data it seems: Azoxystrobin Weak - ELS & LLS Strong - Rust Tebuconazole Weak - LLS Moderate - Rust Strong - ELS Pyraclostrobin Moderate - LLS Weak - ELS Strong - Rust Propiconazole Weak - LLS Strong - ELS Moderate/Strong - Rust
Resistance is a concern, and population diversity is key to understanding control. ELS LLS Rust 2015 Disease Incidence
Rotating modes of action key to disease control when resistance is present. Group 3 Group 7 Group 11 Mixed
Rotating fungicide MOAs, increases the likelihood of a yield savings. 7000 6000 2015 Citra, FL Yield lbs/a 5000 4000 3000 2000 1000 0 y = 876.38x + 673.94 R² = 0.6678 0 1 2 3 4 5 # of Different FRAC Products ~ 900 lb/a increase for each FRA # added
However, net returns tend to max out when 3 modes of action are used. $47.37/A increase in avg. net return with each increase in # of modes of action from 1 to 3
Besides rotating fungicides, cultivar selection is critical to managing resistance.
Cultivar choice can determine the appropriate spray program. Planting Dates: 4/30 and 6/5-2014 5/18-2015 5/11-2016 Cultivars Georgia-06G TUFRunner 511 Florida 07 UF15302 FloRun 107 FloRun157 TUFRunner727 TUFRunner297 Days After Planting 31 40 48 62 76 91 105 112 118 4 Sprays Echo 720 @ 1.5 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a Abound 2.08SC @ 18 fl oz/a + Echo 720 1 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a 5 Sprays Echo 720 @ 1.5 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a Echo 720 @ 1.5 pt/a Abound 2.08SC @ 18 fl oz/a + Echo 720 1 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a 7 Sprays Echo 720 @ 1.5 pt/a Echo 720 @ 1.5 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a Abound 2.08SC @ 18 fl oz/a + Echo 720 1 pt/a TebuStar @ 7.2 fl oz/a + Echo 720 1 pt/a Echo 720 @ 1.5 pt/a
In a low disease situation, varieties responded similarly to spray inputs for yield savings. Yield Increase (lb/a) 5500.00 4500.00 3500.00 2500.00 1500.00 Georgia-06G Yield ~6400 lb/a 0 Sprays 4 Sprays 5 Sprays 7 Sprays 500.00-500.00 GA-06G FL-07 TUFRunner 511 FloRun 107 TUFRunner 727
Similar trends with moderate disease. Yield Increase (lb/a) 5000 4000 3000 2000 1000 Georgia-06G Yield ~2300 lb/a 0 Sprays 4 Sprays 5 Sprays 7 Sprays 0 GA06G UF15302 TUFRunner511 FloRun157 TUFRunner297-1000 UF15302 significantly higher yield with 0 sprays.
However, in a high disease situation, variety is critical to determining yield response from sprays. 6000.00 5000.00 Georgia-06G Yield ~800 lb/a Yield Increase (lb/a) 4000.00 3000.00 2000.00 1000.00 0 Sprays 4 Sprays 5 Sprays 7 Sprays 0.00-1000.00 GA-06G FL-07 TUFRunner 511 FloRun 107 TUFRunner 727 TUFRunner 727 and FL-07 yields were high in reduced spray programs.
Disease resistant cultivars are less affected by spray reductions than more susceptible cultivars. Log (Yield in lb/a) 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 TUF727 0.082 FL07 0.083 GA-06G 0.127 O6G TUF727 FL07 0 1 2 3 4 5 6 7 8 Number of Sprays
Peanut Rx assesses preseason risk of disease, especially with susceptible varieties.
2016 Fungicide Trial Observations 6 th year of continuous peanuts Inoculated with White Mold 2011 and 2012 Inoculated with Rhizoctonia 2012 Planting date: 5/16 Harvest date: 10/16 Variety: Georgia-06G
VelumTotal provided some benefits, but not significant with low nematode pressure. 3000 LSD = 426 2500 2000 Yield (lb/a) 1500 1000 500 0 Untreated Echo Only (24 fl oz) VelumTotal (18 fl oz) VelumTotal (18 fl oz), Propulse (13.7 fl oz)
Elatus continues to perform well and especially with new compound. 6000 5000 LSD = 785 Yield (lb/a) 4000 3000 2000 1000 0
Chemical diversity, timing & number of sprays all important for disease management. 2012-2016 On-Farm Evaluation of Fungicide Programs for Peanut Disease Control in Hamilton County, Florida
Questions?