Sustainable Vegetable Disease Management Daniel S. Egel SW Purdue Ag Center Vincennes, IN
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Anthracnose Gummy stem blight Which is anthracnose & which is gummy stem blight of watermelon? Does it matter?
Products for anthracnose Cabrio chorothalonil Inspire Super mancozeb Pristine Quadris Tanos Products for gummy stem blight Cabrio* chorothalonil Folicur Inspire Super mancozeb Pristine* Quadris* Switch *resistance possible Does it matter? anthracnose
Powdery mildew of pumpkin Downy mildew of pumpkin Powdery mildew exists in the Midwest each year. Downy mildew blows to Midwest some years. Product list for these diseases are very different.
Blossom end rot Late blight Anthracnose Late blight Blossom end rot Anthracnose
Blossom end rot Calcium deficiency Late blight Doesn t overwinter in the Midwest Anthracnose Survives on crop residue
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Most foliar diseases require. Leaf wetness Optimum temperatures Warm for bact. spot of tomato Cool for bact. speck of tomato Powdery mildew requires high humidity only
Foliar fungicide applications Start before disease is observed Approx. 7 to 14 days More often with conducive weather Weather-based disease forecasting program
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Melcast: A Melon Disease Forecasting System Dan Egel, SWPAC Extension Plant Pathologist Bob Mitchell, IT Manager Richard Latin, Professor of Plant Pathology Department of Botany and Plant Pathology
Gummy stem blight of watermelon & muskmelon Anthracnose of watermelon & muskmelon Alternaria leaf blight of muskmelon 14
The EFI Tables The EFI tables were developed from polynomial models that define the influence of leaf wetness duration and temperature on the development of muskmelon and watermelon diseases. With an average temperature of 21C during 20 hrs of LW the WEFI would be 8 and the MEFI would be 5 (table not shown) Watermelon EFI Table
Comparison of application intervals with Bravo Weatherstik (2.75 pt/a) at Lafayette, IN 1998. Application Interval Number of Sprays Amount of Disease (AUDPC) 7-day 9 159.4 h 14-day 5 836.5 b 30 EFI 7 273.7 e-h 35 EFI 6 216.9 f-h 40 EFI 5 418.6 d-h Control 0 1783.0 a
EFI Thresholds: Watermelon-Apply fungicides every 35 EFI Values Muskmelon-Apply fungicide every 20 EFI Values Or every 14 days, which ever comes first.
MELCAST EXTENSION SUPPORT Vegetable Crops Hotline Extension talks One-on-one meetings MELCAST MELCAST Record Book MELCAST Update The Development of Melcast: A Melon
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Fungicide Resistance What is fungicide resistance? MOA codes & fungicide labels Managing fungicide resistance gummy stem blight powdery mildew Bacterial spot of tomato
My fungicide stopped working Why? Severe disease pressure? Improper calibration? Improper rate? Is disease/crop on label? Fungicide resistance?
What is fungicide resistance and why does it happen? Fungicides interrupt normal fungal systems Systems include cell wall development, energy production, protein synthesis etc. Fungicides may have single or multiple MOA. When just single MOA, a single mutation may result in resistance. Population of resistant fungi may increase with repeated use of single MOA fungicide. Low rates of fungicide also encourage resistance.
Two types of Fungicide Mobility Protectants (contact) How do protectant fungicides work? Protectants provide barrier (red line) that stops spore from entering plant and may kill spore on surface Chlorothalonil Mancozeb Courtesy Marty Draper, USDA (modified)
Two types of Fungicide Mobility Systemic Fungicides How do systemic fungicides work? Fungicide absorbed into plant tissue and may move upward or only move locally Prevents spores from entering plant, can stop movement of fungal structures already in plant Cabrio Quadris Pristine Rally Tanos Procure Courtesy Marty Draper
List of single/multiple MOA fungicides Multiple mode of action (mostly contact) Bravo, Echo, Equus Dithane, Manzate, Penncozeb Maneb, Manex Fixed copper Single mode of action (mostly systemic) Quadris Cabrio Endura Pristine (2) Tanos (2)
Code number for MOA (official name- FRAC code). After each application of a group 11 fungicide, choose a different group #. More information about fungicide resistance Can be found in each label.
Group M
Gummy Stem Blight example one
1996 strain of GSB fungussensitive to group 7 fungicideboscalid. 2008 strain of GSB fungusresistant to group 7 fungicideboscalid. Boscalid is group 7 portion of Pristine
List of Didymella bryoniae* strains resistant to fungicides Year Strains tested Strains resistant To boscalid Strains resistant To azoxystrobin 2007 3 2 2 2 2008 9 9 8 8 2009 20 6 11 5 2010 13 8 10 8 Total 45 25 31 23 Percent -- 55% 69% 51% Strains resistant To both *causal agent of gummy stem blight
Powdery Mildew example two
Powdery Mildew Efficacy Assay 400 350 300 Group 1, 11 ineffective Amount of Disease AUDPC 250 200 150 100 50 0 Endura Flint Nova Procure Quintec Topsin Control Group 7 boscalid Group 11 Group 3 Rally Group Fungicide 3 Procure Group 23 Quintec Group 1 Untreated
Bacterial spot of tomato example three
List of strains of bacterial spot strains Year/strain Host Race Copper resistant 07-82 Specialty pepper Pepper 3 No 10-77a Bell pepper Pepper 6 Yes 10-77b Bell pepper Pepper 6 Yes 97-26a Fresh tomato -- Yes 96-41 Fresh tomato -- Yes 07-81 Fresh tomato -- No 09-68a Fresh tomato -- No 10-91 Fresh tomato -- No 10-103 Processing tomato 10-104 Processing tomato -- Yes -- Yes 6 of 10 have copper resistance
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Selected OMRI listed fungicides Active Ingredient Inorganic chemicals Mode of action Multiple Specificity Residual Comments Wide range. Good. Examples include copper & sulfur.
Selected OMRI listed fungicides Active Ingredient Mode of action Hydrogen dioxide Multiple Wide range. Specificity Residual Comments None Examples include OxiDate & StorOx.
Selected OMRI listed fungicides Active Ingredient Mode of action Specificity Residual Comments Anti-microbial compound, induced resistance Wide range. Depends On product. Example: Serenade Max. Microbial Competition Wide range. May survive on plant. Example: T-22. Fungicide compatibility? Hyper-parasite Often specific. Depends on product. Examples: Contans, AQ10. Fungicide compatibility.
Selected OMRI listed fungicides Active Ingredient Mode of action Bicarbonate Multiple. Wide range. Specificity Residual Comments Little or none Potassium most common form. Example: Milstop.
Selected OMRI listed fungicides Active Ingredient Plant extract Mode of action Depends on product. Specificity Residual Comments Usually broad range. Varies. Example: neem, Regalia.
Organic Zucchini-2010 Powdery mildew Treatment, rate/a z % Disease 27 Aug lb./1 Sep Untreated check......... 18.8 a 968 b Serenade Max 3 lbs...... 15.0 ab 1,041 ab Oxidate 90 fl oz........ 12.0 ab 653 b Milstop 2 lbs........... 5.7 bc 726 b Champ DP 3 lbs........ 2.3 c 1525 a P-value 0.0125 0.0965 z Fungicides were applied approximately weekly from 9 until 31 Aug, except Oxidate which was applied twice weekly.
Organic Muskmelon-2010 Alternaria leaf blight Treatment, rate/a z % Disease 23 Jul Total No./A Serenade Max 3 lbs..... 2.9 b 5,639 Oxidate 90 fl oz....... 4.1 ab 5,518 Untreated check........ 7.7 a 4,792 Milstop 2 lbs.......... 3.5 b 5,155 Champ DP 3 lbs........ 2.3 b 4,792 P-value 0.0496 0.6375 z Fungicides were applied approximately weekly from 12 Jun until 29 Jul, except Oxidate which was applied twice weekly.
Treatment, rate/a z Organic Muskmelon-2011 Alternaria leaf blight 12 August % Disease No./plot Milstop 2 lbs............. 68 2.0 Untreated check........... 49 1.8 Milstop/Champ........... 49 2.5 Champ DP 3 lbs.......... 43 2.0 Oxidate 90 fl oz.......... 32 1.3 P-value 0.5882 0.6449 z Fungicides were applied approximately weekly throughout the season.
Outline The Importance of Diagnostics Scheduling Fungicide Applications Weather-Based Disease Forecasting Fungicide Resistance Organic Disease Management Keeping Informed
Information listed in the ID-56 Pesticide resistance Recommended pesticides What pesticides to use in greenhouse Cultural practices to use with what disease Cultivar information Organic, reduced risk, biopesticides
ID-56-production guide Reduced risk pesticide Organic pesticide Biopesticide
ID-56
Information listed in the Hotline New pests What to look for New products Pesticide resistance & efficacy Announcements