AmericanHort provides this on a “Not For Publication” basis Publication of this information, in part or whole, is only permissible through written permission of the author(s) 5/7/2018 Nighttime Application of Light for Control of Plant Diseases Leora Radetsky Jaimin Patel, Ph.D Lighting Research Center Rensselaer Polytechnic Institute July 14, 2018 © 2018 Rensselaer Polytechnic Institute All rights reserved Leora Radetsky © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 Learning Objectives Learning objective 1: › Learn how visible light doses at night can protect plants from powdery mildews and downy mildews Learning objective 2: › Understand how ultraviolet doses at night, with and without visible light, can significantly reduce powdery mildews Learning objective 3: › Learn how to measure ultraviolet and visible light and calculate dosage Learning objective 4: › Learn how controls and sensors play an important role in a lighting solution © 2018 Rensselaer Polytechnic Institute All rights reserved 40-60 concurrent projects at Extensive field studies Research Areas: NVLAP-accredited Advancing the effective use of light • Energy for society and the environment Quick Facts: Graduate education • Technology Development • Human Health Established in 1988 • Plant Health Research and education revenue of $6 million annually • Transportation 30,000 square foot research facility • Outdoor Lighting 34 full-time faculty and staff • Product Testing 15 graduate students • Design • Lighting Metrics © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 Where are we now? Unique capabilities › › › › › › Collaborators › Cornell University Plant pathology › University of Florida Biophysics › University of Vermont Circadian photobiology › Norwegian Institute of Bioeconomy Radiometric measurements Research Fluorescence spectroscopy Funders Industry/academia/ › USDA Specialty Crops Research government collaboration Initiative Strategic approach › USDA Organic Research and Extension Initiative › National Research Council of Norway › North American Strawberry Grower’s Association › USDA Crops at Risk Competitive Grants Program › Flower endowment? › New York Farm Viability Institute › CREE › OSRAM › Science → application › Systematic studies • • • • Spectral sensitivity Dose Additivity Circadian vs diurnal © 2018 Rensselaer Polytechnic Institute All rights reserved Vectors Growing population Increased use of controlled environments Pesticide concerns in the press Increased interest in local products / self sufficiency Labor shortages And, as always, cost-effective solutions © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 We need to feed the world Controlled environments are ideal for pathogens © 2018 Rensselaer Polytechnic Institute All rights reserved We need to feed the world Grape Powdery Mildew Hop Powdery Mildew “Controlled environments optimized for plant growth NOT eliminate pathogens One merely selects pathogens that have evolved to share the environmental optima of their host.” – Dr David Gadoury Diseases destroy crops Losses are focal, shocking, and often catastrophic to individual growers or operations Basil Downy Mildew Strawberry Gray Mold Cucumber Powdery Mildew Potato Late Blight Poinsettia Powdery Mildew © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 Safe to eat? Pesticides in the media © 2018 Rensselaer Polytechnic Institute All rights reserved Location, location, location • Local/regionally produced food is the fastest-growing sector of American agriculture • 80% of organic farms direct sell product within 100 miles • $11B sales in 2014, 10% projected annual growth © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 Automation • Increasing adoption of precision farming technologies • Small increased net returns and profits • Mixed impacts on labor costs © 2018 Rensselaer Polytechnic Institute All rights reserved Innovative solutions are emerging New technologies can be cost effective and increase profits © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 LIGHTING CONTROLS SENSORS Lighting + controls + sensors can provide an “organic” adjunct to pesticides © 2018 Rensselaer Polytechnic Institute All rights reserved The new paradigm for light Amount Spectrum Photosynthesis Distribution Timing Plant Phototransduction Duration Photomorphogenesis Health, Yield, Nutritional Value, Flavor, Appearance Circadian System Amount Pathogen Response Spectrum Distribution Timed Defense Timing Duration © 2018 Rensselaer Polytechnic14Institute All rights reserved 5/7/2018 Our vision: 24-hour lighting scheme for horticulture Light during the day for production Light during the night for pathogen control Electric lighting or daylight during the day Light at night can mitigate pathogens post-infection 15 © 2018 Rensselaer Polytechnic Institute All rights reserved Lighting for plants in the 21st century Technologies › Solid-state lighting • Light-emitting diodes (LEDs) Greater control over › Spectrum • ~365 nm to ~800 nm › Temporal • Duration on/off • Frequency • Phase › Amount HPS • Dimming 470 nm LEDs 660 nm LEDs 625 nm LEDs 470 nm + 660 nm LEDs LED Spatial distribution ã Uniformity 16 â 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 Metrics for greenhouse lighting during the day December 21, Troy, NY 17 © 2018 Rensselaer Polytechnic Institute All rights reserved Project for National Resources Canada 18 © 2018 Rensselaer Polytechnic Institute All rights reserved 5/7/2018 1000 W High Pressure Sodium (HPS) Iso‐PPFD Contours (MH = 2 ft) Photosynthetic Photon Intensity Distribution (Ip, μmol sr‐1 s‐1) Spectral Power Distribution 19 © 2018 Rensselaer Polytechnic Institute All rights reserved LED Iso‐PPFD Contours (MH = 2 ft) Photosynthetic Photon Intensity Distribution (Ip, μmol sr‐1 s‐1) Spectral Power Distribution 20 © 2018 Rensselaer Polytechnic Institute All rights reserved 10 5/7/2018 LED Iso‐PPFD Contours (MH = 2 ft) Photosynthetic Photon Intensity Distribution (Ip, μmol sr‐1 s‐1) Spectral Power Distribution 21 © 2018 Rensselaer Polytechnic Institute All rights reserved Life cycle cost Source Price/fixture Power/fixture ($) (W) 20‐year lifecycle No. of fixtures for cost @ $0.10/kWh ($) 300 µmol m‐2 s‐1 Shading penalty relative to HPS HPS1 540 1070 24 198,500 — LED1 1800 374 63 234,400 +3% LED2 911 358 66 181,400 +42% 22 © 2018 Rensselaer Polytechnic Institute All rights reserved 11 5/7/2018 Lighting / controls / sensors to optimize production Opportunities › Growth and flowering with lower energy and life cycle costs › Enhance nutrition, flavor, shape › Speed up production cycles Metric development is needed 23 © 2018 Rensselaer Polytechnic Institute All rights reserved Jaimin Patel 24 © 2018 Rensselaer Polytechnic Institute All rights reserved 12 5/7/2018 Four recent projects Determine nighttime intervals of red light for suppression of basil downy mildew spores Assess the effects of nighttime red light for increasing basil yield Determine spectral sensitivity (410 nm to 746 nm) of basil downy mildew pathogen Measure the impact of UV-C dose and application intervals on cucumber powdery mildew 25 © 2018 Rensselaer Polytechnic Institute All rights reserved Basil downy mildew 2007 26 © 2018 Rensselaer Polytechnic Institute All rights reserved 13 5/7/2018 Basil downy mildew Symptoms on upper surface of the leaf Pathogen sporulation on under surface of the leaf 27 © 2018 Rensselaer Polytechnic Institute All rights reserved What we know about light’s role for controlling basil downy mildew? Cohen et al 2013, PLOS ONE 8:e81282 Cohen et al 2013, PLOS ONE 8:e81282 CW fluorescent light @ 35 µmol m-2 s-1 for 20 h Dose = PPFD x time (in seconds): 2.52 mol m-2 day-1 Blue=440 nm; Green=500 nm; Red=625 nm Dose = 0.36 – 0.72 mol m-2 day-1 Dark Red-light exposed Dose: 0.43 mol m-2 night-1 28 © 2018 Rensselaer Polytechnic Institute All rights reserved 14 5/7/2018 Nighttime interval of red light for suppression of basil downy mildew sporulation Daytime light hours: a.m – 10 p.m Average PPFD = 130.7 ± 20.6 µmol m-2 s-1 Dose (DLI) = 6.6 moles m-2 day-1 Nighttime conditions Continuous dark Continuous 660 nm 660 nm: h ON 660 nm: 1.3 h ON Cycle (Total h ON) Low Dose (4h): 0.19 mol m-2 night-1 Low Dose (Cont.): 0.48 mol m-2 night-1 Nighttime hours: 10 p.m – a.m Average PPFD = 13.2 ± µmol m-2 s-1 & 59.6 ± µmol m-2 s-1 High Dose (4h): 0.86 mol m-2 night-1 High Dose (Cont.): 2.15 mol m-2 night-1 29 © 2018 Rensselaer Polytechnic Institute All rights reserved Nighttime interval of red light for suppression of basil downy mildew sporulation Sporangia under microscope 30 © 2018 Rensselaer Polytechnic Institute All rights reserved 15 5/7/2018 Benefits of red light at night Enhanced marketability › Appearance › Yield ft x ft modules › Temp: 72° ± 3°F › Dark or red LEDs (max = 625 nm) • Average PPFD: 61 ± 10 µmol m-2 s-1 • On for 10 hours every night • Dose: 2.2 mol m-2 night-1 Dark 625 nm LEDs 31 © 2018 Rensselaer Polytechnic Institute All rights reserved Spectral sensitivity of basil downy mildew sporulation Pre-infection condition Natural day and night cycle for 9-12 days 7am – 7pm 75 µmol m-2 s-1 DLI: 3.2 mol m-2 day-1 Nighttime: visible spectrum and far-red light Irradiance: 0-164 µmol m-2 s-1 Leaf samples in a Petri dish 9-12 days post-infection 32 © 2018 Rensselaer Polytechnic Institute All rights reserved 16 5/7/2018 Sensitivity of basil downy mildew sporulation to spectrum & amount 33 © 2018 Rensselaer Polytechnic Institute All rights reserved Spectral sensitivity of basil downy mildew sporulation 34 © 2018 Rensselaer Polytechnic Institute All rights reserved 17 5/7/2018 UV-C for suppression of cucumber powdery mildew Day: Fluorescent lamp 63.6 ± 1.8 µmol m-2 s-1 for 12h DLI: 2.8 moles m-2 day-1 Night (9 p.m.) dose: UV-C lamp (254 nm) at 7.5, 27 & 75 J/m² Cucumber powdery mildew Conidia 35 © 2018 Rensselaer Polytechnic Institute All rights reserved UV-C for suppression of cucumber powdery mildew No UV-C treatment (dark) UV-C treatment every night UV-C treatment every 2nd night UV-C treatment every 4th night UV-C treatment every 8th night Sporulation Leaf area 36 © 2018 Rensselaer Polytechnic Institute All rights reserved 18 5/7/2018 Summary Light and UV at night can be effective disease control tools, but we are only starting to understand its capabilities Dose is an important factor, not just light level › Controls don’t have to be sophisticated to offer value Sensors must be calibrated and appropriate › PPFD sensors not measure UV or far-red – need an appropriate detector 37 © 2018 Rensselaer Polytechnic Institute All rights reserved Ongoing research Field solutions for squash, strawberry, hops Assessing luminous environments in high tunnels Control of thrips and mites Image processing and artificial intelligence for rapid phenotyping of grape powdery mildew 38 © 2018 Rensselaer Polytechnic Institute All rights reserved 19 5/7/2018 Thank you Dr Jaimin Patel Leora Radetsky Dr Mark Rea Phone: +1-518-687-7100 Email: patelj6@rpi.edu Dr David Gadoury Dr Arne Stensvand Dr Aruppillai Suthaparan Funding USDA Specialty Crops Research Initiative USDA Organic Research and Extension Initiative National Research Council of Norway North American Strawberry Grower’s Association USDA Crops at Risk Competitive Grants Program New York Farm Viability Institute Dr Natalia Peres Dr Bruce Parker Dr Margaret Skinner http://www.lrc.rpi.edu/programs/plants/plants_home.html 39 © 2018 Rensselaer Polytechnic Institute All rights reserved 20