Fungicide Sensitivity of Cold Climate Grape Varieties Patricia - PowerPoint PPT Presentation

Fungicide Sensitivity of Cold Climate Grape Varieties Patricia McManus University of Wisconsin-Madison UW-Extension

Topics • Role of copper and sulfur for disease control in grapes • Research results on copper, sulfur, and difenoconazole, 2012-2015 • Considerations for integrating copper and sulfur into a spray program

Role of Copper and Sulfur in Managing Diseases of Grapes • Copper-based fungicides – Highly effective on downy mildew – Limited activity against other pathogens • Sulfur – Highly effective on powdery mildew – Little or no activity on other pathogens

Role of Copper and Sulfur in Managing Diseases of Grapes • Liquid lime-sulfur, liquid sulfur – Dormant application may have eradicant activity on anthracnose, Phomopsis, and powdery mildew • GREEN TISSUES BURNED BY LIME-SULFUR! DO NOT APPLY AFTER LEAVES EMERGE!

Role of Copper and Sulfur in Managing Diseases of Grapes 1. Fungicide resistance management – Both copper and sulfur act by non-specific disruption of proteins – Still effective after centuries of use – Sterol inhibitors, strobilurins, and others can be overcome by a few mutations in pathogens  fungicide resistance 1. Some forms of copper and sulfur cheaper than synthetic fungicides

Role of Copper and Sulfur in Managing Diseases of Grapes 3. Important in organic production – Some forms of copper and sulfur are approved by OMRI – Copper and sulfur often less expensive than other OMRI-approved products

Topics • Role of copper and sulfur for disease control in grapes • Research results on copper, sulfur, and difenoconazole, 2012-2015 • Considerations for integrating copper and sulfur into a spray program

Sensitivity to copper, sulfur, 2,4-D, and dicamba, as well as disease susceptibility

Lots of Unknowns for Cold Climate Varieties Cultivar BR DM PM Phom. Anthr. S Cu Brianna ? + ? ? ? ? ? Edelweiss ? ? ? ? ? ? ? Maréchal Foch ++ + ++ + ++ Yes Yes Frontenac +++ + ++ + + No ? Frontenac gris ++ + ++ + + No ? La Crescent ++ +++ ++ +++ + ? ? La Crosse +++ ++ ++ ++ + ? ? Marquette +++ + + ? ? ? ? St. Croix ? ++ ++ +++ + ? ? Degree of susceptibility/sensitivity: + = slightly; ++ = moderately; +++ = highly; ? = not known

Fungicide Sensitivity Research • Objective – Determine relative sensitivity of northern varieties to copper, sulfur, and difenoconazole • Collaborators – Matt Stasiak, Brian Shauske, Janet Hedtcke, Victoria Kartanos, Dave Jones—UW-Madison research stations and UW Plant Pathology

Crop injury warning for products containing difenoconazole: Inspire, Inspire Super, Revus Top, Quadris Top

Research Sites and Varieties Brianna Frontenac Frontenac gris La Crescent La Crosse Leon Millot Maréchal Foch Marquette MN1220 PARS 1 & 2 Noiret NY76 Petite Pearl St. Croix Valiant WM1 & WM2 Vignoles

Treatments 1. Cuprofix Ultra 40 or Champ WG, 1.2 - 2 lb actual copper/acre 2. Microthiol Disperss, 8-10 lb micronized sulfur/acre 3. Inspire Super or Inspire, 0.114 lb difenoconazole per acre 4. Non-treated control

Treatments • Applied 2 to 6 times at 2- to 3-week intervals in May- Aug 2012, 2013, 2014, 2015 (11 trials total) • Applied without adjuvants and not mixed with other pesticides

Data Collection • About every 2 weeks, foliage rated for injury 1 = no visible injury 2 = minor injury 3 = moderate injury 4 = severe injury • For any given trial, same person did ratings weekly season-long • Toxicity = average rating of 2.5 and statistically different from non-treated control

Copper injury on Brianna, PARS 2012

Copper injury on Marquette, WMARS, 4-Sep 2013

Sprayed with sulfur Foch at Peninsular Station, 2013

Sprayed with sulfur Sprayed with copper Foch at Peninsular Station, 2012

Sensitivity to Copper 1 2 3 4 5 6 7 8 9 10 11 Brianna M. Foch Frontenac Fronten gris LaCrescent LaCrosse Leon Millot Marquette MN1220 Noiret NY76 Petite Pearl St. Croix Valiant Vignoles

Sensitivity to Copper • Do not apply copper to Brianna • Restrict copper to 1-2 sprays/season on Frontenac, Frontenac gris, LaCrescent, Leon Millot, Maréchal Foch, Marquette, and St. Croix

Sensitivity to Sulfur 1 2 3 4 5 6 7 8 9 10 11 Brianna M. Foch Frontenac Fronten gris LaCrescent LaCrosse Leon Millot Marquette MN1220 Noiret NY76 Petite Pearl St. Croix Valiant Vignoles

Sensitivity to Sulfur • Do not apply sulfur to Maréchal Foch, Leon Millot, or Brianna • Restrict sulfur to 1-2 sprays/season on LaCrescent and St. Croix

Sensitivity to Difenoconazole • Noiret was sensitive in 1 of 2 trials • The following varieties were tested in at least 3 trials, and none were sensitive: – Brianna, Frontenac, Frontenac gris, LaCrescent, LaCrosse, Leon Millot, Maréchal Foch, Marquette, NY76, St. Croix, Valiant, and Vignoles

Topics • Role of copper and sulfur for disease control in grapes • Research results on copper, sulfur, and difenoconazole, 2012-2015 • Considerations for integrating copper and sulfur into a spray program

Integrating Copper and Sulfur into a Spray Program Initial considerations • Do you have a good reason to try Cu and/or S? – Organic – Resistance management – Economics • Do you have any Cu or S sensitive varieties? • Are Cu and S compatible with other products you rely on?

pH and Copper Solubility • At lower pH, copper ions released from “fixed” fungicides more quickly • Copper fungicides should not be mixed with phosphorous acid fungicides or any product that will reduce pH below 6.5 • Because some forms of copper are persistent, consider the interval between copper and PA fungicide sprays

Integrating Copper and Sulfur into a Spray Program Further considerations • Do you need post-infection activity? – Cu strictly protective, needs to go on before infection – S primarily protective, but good post-infection control up until time that PM growth appears – Other fungicides provide better post-infection activity against DM and PM

Integrating Copper and Sulfur into a Spray Program • Weather at time of application and within 24 hours after – Hot temps increases risk of S injury – Cool temps, prolonged wetness increase risk of Cu injury

Integrating Copper and Sulfur into a Spray Program • “Weathering” of fungicides after application – S especially subject to wash off with 1-2 inches rain – Micronized forms of Cu and S more weather-fast than wettable powder

Thank You! Questions?

Vine N Nutri rition on of of C Col old-Hard rdy Cultiva vars Carl Rosen sen a and J d James es Crants Department o of S Soil il, Water, and Clim imate Un Univ iversit ity of Min innesota Northe hern n Grape pes P Project W Webi bina nar April 12, 2, 201 2016

Collaborators Tim Martinson and Chrislyn Particka, Cornell University Paul Domoto and Diana Cochran, Iowa State University Harlene Hatterman-Valenti, North Dakota State University Rhoda Burrows and Anne Fennell, South Dakota State University

Background  Recently developed cold hardy grape varieties offer new opportunities for winemaking  Optimal nutrition and soil management practices have not been established  Tissue analysis is a tool used to assess nutritional status, but critical values are based on V. labrusca and V. vinifera  Values may need to be adjusted for cold hardy varieties, which have a V. riparia background 

Background  Tissue analysis is traditionally based on petioles samples  The use of petioles has come into question, even for traditional varieties  Leaf blade tissue or whole leaf (petiole + blade) may be a better indicator of nutritional status

Background  Optimum petiole sampling time?  Bloom  +: more time to correct issues  -: nutrient concentrations unstable  Veraison  +: concentrations stable  predict nutrient needs for next year  -: little time to address problems before harvest

Current Petiole Guidelines Element Bloom Veraison N (%) 1.60 - 2.50 0.90 - 1.3 Values tabulated by P (%) 0.16 - 0.60 0.13 - 0.40 Rosen and Domoto K (%) 1.50 - 4.00 1.50 - 2.50 S (%) no data no data Ranges based on Ca (%) 0.40 - 1.50 1.20 - 1.80 data from V. vinifera Mg (%) 0.20 - 0.40 0.26 - 0.45 and V. labrusca Zn (ppm) 20 - 100 20 - 40 Fe (ppm) 40 - 180 30 - 100 Western and Eastern Mn (ppm) 20 - 150 30 - 150 U.S. research Cu (ppm) 5 - 10 5 -15 B (ppm) 25 – 50 25 - 50

Overall Objectives  Establish/fine-tune nutrient diagnostic criteria and interpretations for recently released cold hardy grape cultivars  Determine relationships between soil characteristics and tissue nutrient levels (petiole, blade, whole leaf) and juice quality

14-16 Study Sites, 3 Years Used in 1 – 2 seasons Used in all 3 seasons