UV-C Light Application Technology for Field-Grown Strawberries to Control Fungal Diseases and Arthropod Pests

Progress report for LNE20-411R

Project Type: Research Only
Funds awarded in 2020: $187,733.00
Projected End Date: 09/30/2022
Grant Recipients: Appalachian Fruit Research Station, US Department of Agriculture, Agricultural Research Service; TRIC Robotics
Region: Northeast
State: West Virginia
Project Leader:
Dr. Fumiomi Takeda
Appalachian Fruit Research Station, US Department of Agriculture, Agricultural Research Service
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Project Information

Summary:

Problem, Novel Approach and Justification:  Strawberry farmers in the Northeast use synthetic pesticides to manage persistent diseases and arthropod pests (e.g. Botrytis fruit rot, powdery mildew, anthracnose, whitefly, and two-spotted spider mite).  This can be costly due to expenses of the treatment.  With the threat of pesticide resistance and increasing annual costs for growers (currently ~$500/acre in the Northeast), alternative strategies are needed for managing diseases and pests.  A novel non-chemical strategy we have developed for this purpose is called PhylloLux technology.  This innovative method uses a relatively low UV-C light dose combined with a prescribed dark period and application of beneficial microbes (antagonists) to control fungal pathogens (e.g. Botrytis cinerea, Colletotrichum acutatum and C. gloeosporioides and Podosphaera aphanis).  Night-time UV-C light applications is a strategy that maximizes killing power on microorganisms at levels that are not damaging to strawberry plants.  Our research also showed that this technology decreases populations of whitefly (Trialeurodes vaporariorum) and two-spotted spider mite (Tetranychus urticae) populations.  Autonomous nighttime robotic operation for UV-C light application will have a minimal impact on day-active pollinators and does not require no personnel to work in the dark. 

Hypothesis or Question and Research Plan:  PhylloLux technology will be developed as an affordable non-chemical alternative to pesticides for management of strawberry diseases and pests via automation.  USDA will collaborate with TRIC Robotics to develop an autonomous vehicle for the delivery of UV-C technology to field-grown strawberry plants that is affordable and effective for managing persistent diseases and pests.   

Outreach Plan:  We will recruit growers and extension personnel to join a stakeholder-driven and insightful advisory panel.  The panel will be comprised of strawberry growers in WV, MD, DE, and MA and berry crop extension educators/researchers in ME, MA, CT, PA, and MD to guide this “novel approaches” project.  Annual in-person advisory panel meetings will be held along with several e-meetings to enable the panel to provide real-time input into the project. Based on panel feedback, researchers will modify work as necessary.  A project website/blog will be created to post findings as part of outreach education and to obtain feedback from stakeholders.  Research activities and significant findings will be shared with stakeholders at regional and national berry conferences and in popular publications. 

Project Objective:  The objective of our proposal is to improve control of persistent disease and arthropod pests of strawberry and decrease pesticide use by deploying an autonomous vehicle that applies UV-C light to strawberry fields at night.  We will compare disease and pest control achieved with synthetic pesticides, UV-C and the combination on short-day and day-neutral strawberry varieties.  We will work specifically with TRIC Robotics to make this technology affordable and commercially feasible for small-scale strawberry growers in the Northeast.

Project Objective:

The objective is to improve control of persistent disease and arthropod pests of strawberry while decreasing pesticide use by deploying an autonomous vehicle that applies UV-C light to strawberry fields and is affordable for small-scale growers.  We will compare disease and pest control achieved with synthetic pesticides, UV-C and the combination on two strawberry varieties.  We will work specifically with TRIC Robotics technologies to make this system affordable and commercially feasible. 

Introduction:

Strawberry farmers in the Northeast use repeated pesticide applications to manage persistent disease and arthropod pests.  With the threat of pesticide resistance and increasing costs for growers (currently $500/acre season-long), alternatives are needed.  A novel non-chemical strategy has been developed for this purpose by USDA scientists.  This innovative method uses a relatively low UV-C light dose combined with a prescribed dark period to control fungal diseases.  Nighttime UV-C application also decreases white fly and two-spotted spider mite populations.  There was a need to develop an autonomous vehicle for the delivery of UV-C technology to field-grown strawberries that is affordable and effective for managing persistent diseases and pests.  In 2020, a planting of 'Albion' strawberry was established in plasticulture system.  A robot was designed and manufactured by our cooperator TRIC Robotics with UV-C light array mounted on its frame.  A program was developed to enable the robot to apply UV-C treatment at night on specified plots within a 12 row x 4 plots per row field planting.  Night-time UV-C applications were made at least twice per week from early August to early November.  Our UV-C technology application on field-grown plants twice a week had no deleterious effects on strawberry plants.  Unfortunately, two-spotted spider mite or insect infestation did not occur in any of the plots even in control plots at Kearneysville, WV location.  An ancillary study in Delaware clearly showed a reduction of two-spotted spider mite population in UV-C treated plots and in a grower field an early yield increases were recorded in UV-C treated plots compared to non-irradiated plots.  In 2021, the plan is to infest all plots with TSSM early in the season and before UV-C and chemical treatments are initiated.  The robot performance was reliable such that the robots will be deployed on two commercial strawberry farms in January 2021 for a season-long evaluation of insect/mite control and mechanical reliability evaluations.   A tremendous interest for UV-C technology was expressed by growers in SC, TN, CA, PA, MD, DE, and Canada and write-ups for several grower magazines were prepared.   Requests for UV-C presentations by the bramble and blueberry grower organizations were received and accepted.

 

Cooperators

Click linked name(s) to expand
  • Dr. Adam Stager (Researcher)

Research

Materials and methods:

Hypothesis:  Automation makes feasible for making UV-C treatments at night feasible.  A robotic system for field-grown strawberries can be developed at a cost that is affordable to small-scale strawberry berry farmers in the Northeast.  PhylloLux technology can be developed as a non-chemical alternative to pesticides for control of strawberry diseases and pests.  

Materials and methods:  A new field plot at the Appalachian Fruit Research Station was established in early June 2020 with raised beds covered with black plastic mulch.  Bare-root plants of Albion were inserted through slits in the plastic and into moistened soil.  Transplants were drip irrigated daily until transplants were well rooted.  Thereafter, the plots were irrigated and fertilized as needed.  UV-C irradiation treatments were initiated in early August.  The designated plots were irradiated between 10 am and 1 pm two night each week until early November 2020.  Data for flowering responses were collected 3 weeks apart.  Weekly scouting was performed to ascertain TSSM and insect infestation.  Robot travel control system was modified as needed to fine tune the travel down the row and make the turns at the ends of the row to go more smoothly.  Other electronic components of the CPU controlling the robot was modified to improve GPS signal reception.  

Research results and discussion:

Our research refined the engineering aspects of the robot technology and optimized the UV-C system to make the UV-C technology economically competitive with conventional chemical control approaches.  Further field-based validation confirmed the efficacy of the system as noted by reduction in two spotted spider mite counts.  The prototype autonomous mobile UV-C irradiation unit traveled over multiple strawberry rows under field conditions and was able to make smooth turns at the end of the rows to treat other specialty crops. 

Currently we are evaluating ways for reducing the duration and frequency of exposure, comparison of daytime and night-time applications, and addressing the need for deeper penetration of UV-C light into plant canopy.  Reflective surfaces for the UV-C light array has been fine-tuned to increase light penetration to underside of leaves.  The results also suggested that the robot can be modified to incorporate UV-C light at different wavelengths to improve the capacity enable it to travel at greater speeds and operate effectively during daytime hours.  These modifications will allow the robot to cover much larger areas in a given time.  These improvements should make the UV-C/robot technology more attractive for larger strawberry growers  

The positive results obtained from night-time application and relatively low doses of UV-C irradiation for controlling fungal pathogens and arthropod pests to date indicate the potential of UV-C treatments to reduce disease incidence and alter insect behavior impacting their herbivory and egg laying.  We will continue to explore the efficacy of the UV-C irradiation system for management of pestiferous mites and insects on other specialty crop plants.  T USDA is now collaborating with TRIC Robotics (https://www.tricrobotics.com) which has highly skilled robot engineers, manufacturing capacity, and provides on-the-go solutions for autonomous UV-C application in soil-grown specialty crops.  T

Participation Summary
1 Farmer participating in research

Education & Outreach Activities and Participation Summary

Educational activities:

5 Consultations
4 Published press articles, newsletters
3 Webinars / talks / presentations

Participation Summary:

200 Farmers
50 Number of agricultural educator or service providers reached through education and outreach activities
Outreach description:

Outreach activities include presentations on UV-C technology at the 2020 North American Strawberry Growers Association annual meeting (200 people in the audience) and a 90-minute workshop on UV-C technology with ~30 strawberry growers from 10 U.S. states and Canada.  A short presentation was given (virtual) on UV-C technology for disease and pest management at the 2020 N. American Raspberry and Blackberry Association annual conference (20 berry farmers).  Dr. Takeda was the invited speaker for the June 2020 Northeast Berry Educators conference call hosted by Cornell University where he made a presentation on UV-C technology (~30 extension educators from the Northeast on the call).  

Learning Outcomes

6 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
10 Service providers reported changes in knowledge, attitudes, skills and/or awareness as a result of project outreach
10 Educators or agricultural service providers reported changes in knowledge, skills, and/or attitudes as a result of their project outreach
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:
 
 
 

We understand that all farmers and service providers included in the numbers entered above may not have gained knowledge in all areas described below.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.