Root Rot: Have you heard (or had) enough yet? Julie Pasche Pulse Crop Pathology Group Julie.Pasche@NDSU.edu 701-231-7077 1
Pulse Pathology Dr. Michael Wunsch Carrington REC Audrey Kalil Williston REC Fargo Pathology Group Dr. Kirstin Simons Dr. Kim Zitnick-Anderson Amanda Beck Cecilia Monclova-Santana Chryseis Modderman Robin Lamppa 2
Root Rot Management An integrated approach Breeding for resistance to root rots Seed treatments Planting date (temperature) Cereal residue 3
Breeding for Resistance Two types of resistance Major gene Typically a single gene Provides a high level of resistance Minor gene Usually multiple genes Provides a lower level of resistance 4
Major (Single) Gene Resistance Photos: Kevin McPhee 5
Partial (Multiple Gene) Resistance 6
Breeding for Partial Resistance Difficulty of breeding for root rot resistance Genes confer partial resistance Unstable outside influences Environment Pathogen population Additive affects Combine genes through breeding 7
Aphanomyces resistance genes Hamon et al (2013); Desgroux et al. (2016) 8
Aphanomyces resistance genes Higher number of partial resistance genes in most resistant lines Most resistant lines More resistance genes Most susceptible lines Few to no resistance genes Desgroux et al. (2016) 9
Breeding for Aphanomyces Resistance 10 Desgroux et al. (2016)
Breeding for Root Rot Resistance Progress has been made breeding for resistance to root rot pathogens Resistance is not (and will likely not be) complete Understanding the pathogen populations is critical We continue to evaluate other management strategies 11
Root Rot Management An integrated approach Breeding for resistance to root rots Seed treatments Planting date (temperature) Cereal residue 12
Pathogen complex Pythium spp. Pulse Crop Root Rot Mefenoxam / metalaxyl is effective Several products available Rhizoctonia solani Fusarium spp. Aphanomyces euteiches 13
Rhizoctonia: Seed Treatment Efficacy Product ApronMaxx (no inoculum) Rate (fl oz/cwt) Chickpeas 2016 Plants / acre Chickpeas 2017 Lentils 2017 Peas 2017 5.0 No data 160,550 388,306 278,962 ApronMaxx 5.0 50,405 28,003 95,210 294,430 VibranceMaxx 5.0 169,262 107,655 248,914 301,897 VibranceMaxx + Mertect 5.0 + 0.47 158,683 136,903 294,963 297,630 Obvius 5.9 182,952 135,036 309,898 306,698 Rhizolex + Allegiance + Mertect 0.3 + 0.75 + 1.02 No data 105,166 213,444 277,362 Courtesy: Dr. Michael Wunsch Carrington REC
Rhizoctonia: Seed Treatment Efficacy Product ApronMaxx (no inoculum) Rate (fl oz/cwt) Chickpeas 2016 Yield (pounds / acre) Chickpeas 2017 Lentils 2017 Peas 2017 *(bushes/a) 5.0 No data 3465 1826 45 ApronMaxx 5.0 1392 2484 1194 42 VibranceMaxx 5.0 1761 3057 1940 46 VibranceMaxx + Mertect 5.0 + 0.47 1833 3229 1994 51 Obvius 5.9 1630 3280 2068 50 Rhizolex + Allegiance + Mertect 0.3 + 0.75 + 1.02 No data 3037 1840 46 Courtesy: Dr. Michael Wunsch Carrington REC
Fusarium: Seed Treatment Efficacy 1. Fludioxonil: Maxim 4ST, Spirato 480ST, etc. 2. Evergol Energy (penflufen + prothioconazole) 3. VibranceMaxx (fludioxonil + sedaxane) 4. Obvius (pyraclostrobin + fluxapyroxad) All seed was treated with metalaxyl / mefenoxam Courtesy: Dr. Michael Wunsch Carrington REC
Fusarium: Seed Treatment Efficacy 1. Fludioxonil, 1.14 g ai/cwt (Maxim 4ST, Spirato 480ST, etc.) Improved plant population in 4 of 6 trials Improved yield in 3 of 6 trials 2. Evergol Energy, 1.0 fl oz/cwt (Metalaxyl, + Penflufen, + Prothioconazole) Improved plant population in 1 of 2 trials No yield increases were observed Courtesy: Dr. Michael Wunsch Carrington REC
Fusarium: Seed Treatment Efficacy 3. VibranceMaxx, 1.54 fl oz/cwt (Mefenoxam + Fludioxonil + Sedaxane) Improved plant populations in 3 of 4 trials Improved yield in 1 of 4 trials 4. Obvius, 4.6 fl oz/cwt (Metalaxyl + Pyraclostrobin + Fluxapyroxad) Improved plant populations in 2 of 3 trials Improved yield in 2 of 3 trials Courtesy: Dr. Michael Wunsch Carrington REC
Aphanomyces: Seed Treatment Efficacy Control of Aphanomyces with seed treatments is difficult: Aphanomyces root rot develops during vegetative growth and bloom The concentration of fungicide in the target tissues (tap root, epicotyl) is low Ethaboxam (Intego Solo): registered on lentils and chickpeas Best at the 0.3 fl oz/cwt rate Results have been mixed - inconsistent Courtesy: Dr. Michael Wunsch Carrington REC
Seed Treatment Efficacy A seed treatment is recommended A basic seed treatment may suffice under lower disease pressure Observed additional benefit from a combination of multiple active ingredients when disease pressure is high Results vary by environment If you have had success from a seed treatment in your fields, stick with it
Root Rot Management An integrated approach Breeding for resistance to root rots Seed treatments Planting date (temperature) Cereal residue 21
Aphanomyces - Response to planting date (field peas) Courtesy: Dr. Michael Wunsch Carrington REC Variety: DS Admiral (yellow-cotyledon type) Seeding rate: 300,000 pure live seeds/ac Direct-seeded into wheat stubble Seed treatment: Apron XL 0.16 fl oz/cwt + Apron Maxx RFC 1.5 fl oz/cwt + Rizolex 0.3 fl oz/cwt +/- Intego Solo 0.2 fl oz/cwt Pathogen isolation: Fusarium sp. from 16% of roots (early planting date), 8% (intermediate), 25% (late) Pathogen isolation: Aphanomyces sp. from 2% of roots (early planting date), 13% (intermediate), 0% (late)
Aphanomyces - Response to planting date (field peas) Courtesy: Dr. Michael Wunsch Carrington REC Variety: DS Admiral (yellow-cotyledon type) Seeding rate: 300,000 pure live seeds/ac Direct-seeded into wheat stubble Seed treatment: Apron XL 0.16 fl oz/cwt + Apron Maxx RFC 1.5 fl oz/cwt + Rizolex 0.3 fl oz/cwt +/- Intego Solo 0.2 fl oz/cwt Pathogen isolation: Fusarium sp. from 16% of roots (early planting date), 8% (intermediate), 25% (late) Pathogen isolation: Aphanomyces sp. from 2% of roots (early planting date), 13% (intermediate), 0% (late)
Fusarium - Response to planting date Courtesy: Dr. Michael Wunsch Carrington REC Variety: Abarth (yellow-cotyledon type) Seeding rate: 330,000 pure live seeds/ac Direct-seeded into wheat stubble Seed treatment: Gaucho 1.6 fl oz/cwt + Evergol Energy 1.0 fl oz/ac +/- (with or without) fluopyram 0.05 mg ai/seed Pathogen isolation: Fusarium sp. from 31% of roots (early planting date), 26% (intermediate), 26% (late) Pathogen isolation: Aphanomyces sp. from 0% of roots (early planting date), 0% (intermediate), 0% (late)
Fusarium - Response to planting date Courtesy: Dr. Michael Wunsch Carrington REC Variety: Abarth (yellow-cotyledon type) Seeding rate: 330,000 pure live seeds/ac Direct-seeded into wheat stubble Seed treatment: Gaucho 1.6 fl oz/cwt + Evergol Energy 1.0 fl oz/ac +/- (with or without) fluopyram 0.05 mg ai/seed Pathogen isolation: Fusarium sp. from 35% of roots (early planting date), 29% (intermediate), 28% (late) Pathogen isolation: Aphanomyces sp. from 0% of roots (early planting date), 0% (intermediate), 0% (late)
Fusarium Field Evaluations F. solani Non-inoculated F. avenaceum Photo: Jennifer Odom 26
Fusarium Field Evaluations 80 2015 2016 Emergence (%) 60 40 20 0 F. solani F. avenaceum Inoculum Odom et al, unpublished 27
Fusarium Field Evaluations 60 2015 2016 Yield reduction (%) 40 20 0 F. solani F. avenaceum Inoculum Odom et al, unpublished 28
Fusarium Field Evaluations Soil temperature At planting ( o F) Ave 2 wks postplanting ( o F) 2015 50 56 2016 61 67 Damage caused by pathogens varies as a result of environmental conditions Extremely important for: o o Breeding for resistance Development of other management strategies 29
Root Rot Management An integrated approach Breeding for resistance to root rots Seed treatments Planting date (temperature) Cereal residue 30
Cereal Residue and Root Rot 5 Root rot severity (0-5) 4 3 2 1 0 0 20 40 60 80 100 Ground cover (%) 31
Cereal Residue and Root Rot 5 Root rot severity (0-5) 4 3 2 1 0 0 1 2 3 Residue depth (in) 32
Cereal Residue and Root Rot Number of isolates 250 200 150 100 50 0 Fusarium recovered from Cereal Residue Straw Residue Duff Residue 33
Lentil Root Rot Severity Root development Enhanced plant growth Enhanced nutrient uptake Courtesy of Audrey Kalil - WREC Mapping credit: Charitha Hettiarachchi (NDSU)
Fusarium species from Lentil 40 Frequency (%) 30 20 10 0
Fusarium species from Lentil Field pea and lentil Fusarium root rot pathogens are very similar Both crops are also susceptible to Aphanomyces root rot These should not be considered rotations as far as root rot are considered Pea Cereal Lentil Cereal Pea This is a 2-year root rot rotation
Thank You Julie.Pasche@NDSU.edu 701-231-7077 Photo: Jennifer Odom 37