Source: WASHINGTON STATE UNIVERSITY submitted to NRP
TOWARDS A SUSTAINABLE BIOECONOMY: AN ECO-FRIENDLY NATURE-INSPIRED BIOPESTICIDE DELIVERY SYSTEM FOR IMPROVED CONTROL OF PLANT DISEASES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1032404
Grant No.
2024-68016-42483
Cumulative Award Amt.
$999,591.00
Proposal No.
2023-09467
Multistate No.
(N/A)
Project Start Date
Jul 1, 2024
Project End Date
Jun 30, 2028
Grant Year
2024
Program Code
[A1414]- Bioenergy Feedstock Logistics Program
Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
(N/A)
Non Technical Summary
Conventional agrochemicals (e.g., antibiotics and synthetic pesticides) adversely impact the economy, environment, and human health due to significant spray loss and antibiotic resistance emergence. Biopesticides have emerged as an alternative strategy to conventional agrochemicals. However, their real-world performance remains weak, resulting in a low market share. This is due to their instability under field conditions and significant spray loss and runoff from hydrophobic plant surfaces. The goal of this integrated project is to enhance the biocidal efficacy of biopesticides by improving their stability under field conditions and to reduce spray loss and runoff by improving drop retention on hydrophobic plant surfaces, thereby promoting sustainable agricultural practices. Specific research objectives are: 1) develop bio-based microcarriers for encapsulating microbial and biochemical pesticides to enhance biopesticide stability under simulated field conditions; 2) engineer bio-based microcarriers with organic-certified surfactant to enhance biopesticide delivery and retention on hydrophobic plant surfaces; 3) demonstrate the enhanced biocidal efficacy of new biopesticide formulations against fire blight in greenhouse and field trials; and 4) assess biopesticide knowledge and attitudes among stakeholders and consumers, and offer trainings for students and industry professionals. Success in this project will promote the deployment of these biopesticides, offering enhanced functionality and stability for managing plant diseases in organic production and providing sustainable alternatives to antibiotics and synthetic pesticides commonly used in conventional production. The long-term impact of this research is in support of Program Area Goals to develop bio-based products that improve product functionality, increase potential revenues and/or reduce cost over incumbent products.
Animal Health Component
40%
Research Effort Categories
Basic
10%
Applied
40%
Developmental
50%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21511102020100%
Knowledge Area
215 - Biological Control of Pests Affecting Plants;

Subject Of Investigation
1110 - Apple;

Field Of Science
2020 - Engineering;
Goals / Objectives
The long-term goal of this Integrated Project is to enhance the biocidal efficacy of biopesticides by improving their stability under field conditions and to reduce spray loss and runoff by improving drop retention on plant surfaces, thereby promoting sustainable agricultural practices. Specific research objectives are: 1) develop bio-based microcarriers for encapsulating microbial and biochemical pesticides to enhance biopesticide stability under simulated field conditions; 2) engineer bio-based microcarriers with organic-certified surfactant to enhance biopesticide delivery and retention on hydrophobic plant surfaces; 3) demonstrate the enhanced biocidal efficacy of new biopesticide formulations against fire blight in greenhouse and field trials; and 4) assess biopesticide knowledge and attitudes among stakeholders and consumers, and offer trainings for students and industry professionals.
Project Methods
OBJECTIVE 1: Develop bio-based microcarriers for encapsulating microbial and biochemical pesticides to enhance biopesticide stability under simulated field conditions.Bio-based sporopollenin and yeast microcarriers are used to encapsulate both microbial and biochemical pesticides. These two bio-based microcarriers offer exceptional loading efficiency for diverse biopesticides and enhance their stability when exposed to environmental conditions, such as sunlight, desiccation, and elevated temperatures often encountered in the field. The rationale for selecting these two carriers is based on the unique compositional and structural characteristics inherent in plant pollen grains and yeast cells, as illustrated in our preliminary results. Furthermore, the chosen pollen grains and yeast cells originate from plant sources or naturally interact with fruit trees. The sub-aims are (1) preparation and characterization of sporopollenin and yeast microcarriers; (2) encapsulation of microorganisms (phages and non-spore-forming BCAs); (3) encapsulation of plant extracts.OBJECTIVE 2: Engineer bio-based microcarriers with organic-certified surfactant to enhance biopesticide delivery and retention on hydrophobic plant surfaces.Surface engineering of SECs and YMs using food-grade adhesive polydopamine (PDA) and organic-certified organosilicon surfactant siloxane polyalkyleneoxide copolymers (SPC) will mitigate spray loss and improve droplet retention on hydrophobic plant surfaces, leading to enhanced delivery and biocidal efficacy of biopesticides. Using PDA and SPC, a lamellar-like micelle structure will be formed on the surface of microcarriers, regulating impact splash and extending the dispersion of droplets. The techniques of double-casting microreplication and high-speed photography allow investigation of single drop impact on complex apple blossom petals. The sub-aims are (1) surface engineering of bio-based microcarriers and characterization of their physicochemical properties; (2) assessment of the engineered microcarriers in improving droplet retention on plant surfaces.OBJECTIVE 3: Demonstrate the enhanced biocidal efficacy of new biopesticide formulations against fire blight in greenhouse and field trials.We will assess the spray retention and biocidal efficacy of new pesticide formulations in real production conditions. Alongside guiding materials development in Objectives 1 & 2, we will evaluate their performance on whole plants in a greenhouse, simulating high UV irradiation and low humidity conditions. The greenhouse experiments will aid in identifying the three most promising biopesticide composites for field trials. Further studies will demonstrate field-relevant performance of the proposed biopesticide formulations. By characterizing disease prevalence under normal operating conditions, we aim to showcase the practical efficacy of these biopesticide formulations in real-world scenarios. The sub-aims are (1) assessment of biopesticide performance on whole plants in greenhouse; and (2) in-situ field plot spray assay.OBJECTIVE 4: Assess biopesticide knowledge and attitudes among stakeholders and consumers, and offer trainings for students and industry professionals.Survey development serves as a crucial initial step for gathering insights and knowledge from growers, chemical companies, and consumers, informing the development of extension and education programs (workshops and online courses) to address specific needs and challenges faced by the target audiences. In-person workshops facilitate interactions between extension specialists and stakeholders, while online training modules provide flexible learning for both students and industry professionals. The effectiveness of both workshops and online courses will be assessed to enhance and refine these initiatives. The sub-aims are (1) evaluation of stakeholders' and consumers' current knowledge and attitudes towards biopesticide application in agriculture; (2) development and delivery of in-person workshops and online training courses for students and agriculture industry professionals; and (3) evaluation and measurement of learning outcomes from in-person workshops and online training courses.

Progress 07/01/24 to 06/30/25

Outputs
Target Audience:Over the past year, this project has served multiple target audiences. Graduate and undergraduate students acquired practical skills in experimental design, biopesticide encapsulation, material synthesis and characterization, and microbiology through lab-based learning. Graduate students and postdoctoral researchers also enhanced their technical writing and mentorship abilities by supervising undergraduate researchers contributing to the project. The biopesticide research community benefited from the dissemination of new scientific knowledge via journal articles and conference presentations. The agrochemical industry received valuable insights into innovative approaches for improving the stability and biocidal performance of biopesticide materials in agricultural applications. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided research training for two undergraduate students, two graduate student, and two postdoctoral scholars. Through this interdisciplinary experience, participants engaged in both laboratory research and outreach activities. They were given opportunities to present their work at various levels, including lab meetings, campus events, national conferences, and through technical journal publications. The postdoctoral researcher also took on mentorship responsibilities, providing technical guidance to undergraduate and junior graduate students. Additionally, the collaborative environment fostered by this project has led to meaningful cross-disciplinary research among team members. How have the results been disseminated to communities of interest?Knowledge generated from this project has been shared with both scientific communities and the general public. Four presentations delivered at national and international conferences. Research findings were presented at the 2025 ASABE Annual International Meeting in Anaheim, CA, the IAFP conference 2024 in Long Beach, CA, the Conference of Food Engineering in Seattle, WA, and the NC-1023 Seminar Series. To date, two peer-reviewed articles has been published, with three additional manuscripts currently under review. Furthermore, WSU is organizing the 4th International Symposium on Fire Blight of Rosaceous Plants, which is held in Richland, WA, USA, from June 23 to 27, 2025. What do you plan to do during the next reporting period to accomplish the goals?In the next reporting period, we will focus on three major efforts. First, we will utilize plant pollen grains and yeast cells to encapsulate essential oils and/or plant byproduct-derived extract, aiming to enhance the stability of biopesticides under simulated field conditions. Second, we will evaluate the efficacy of the new biopesticide formulations against fire blight in greenhouse trials. Third, we will assess stakeholders' and consumers' current knowledge and attitudes to identify potential barriers to the acceptance and adoption of new biopesticides.

Impacts
What was accomplished under these goals? This project has advanced the development of sustainable biopesticide delivery systems by integrating multiple bio-based strategies. The key accomplishments are summarized as follows: (1) Development of novel biobased microcarriers using sporopollenin exine capsules (SECs) to encapsulate bacteriophages. (2) Surface engineering of yeast-based microcarriers to improve delivery efficiency and retention of biopesticides on hydrophobic plant surfaces. (3) Formulation of a bio-inspired antimicrobial system by encapsulating thymol in SIF-modified yeast microcarriers. (4) Extraction and evaluation of phenolic-rich antimicrobials from agricultural byproducts (olive and pomegranate pomace). We successfully demonstrated the use of sporopollenin exine capsules (SECs) to improve phage stability and antimicrobial efficacy. Using an innovative vacuum infusion-based encapsulation method, SECs achieved high-efficiency phage loading while preserving viability and activity. Acting as physical barriers and UV absorbers, SECs protected phages from UV damage, enhancing their stability and biocidal performance under simulated field conditions. These results highlight the robustness of SEC-based phage delivery systems with potential applications in agriculture. Additionally, we developed a surface engineering approach for yeast-based microcarriers using food-grade ε-poly-L-lysine and sodium dodecyl sulfate. This method reduced suspension surface tension, improving droplet spreading and retention on hydrophobic plant surfaces. Compared to conventional methods, the engineered yeast suspensions exhibited superior droplet dynamics, supporting more effective microcarrier distribution and reducing spray loss. A bio-inspired antimicrobial formulation was developed by encapsulating thymol in yeast-based microcarriers. In this approach, yeast microcarriers were pre-treated with simulated intestinal fluid (SIF) to modulate their microstructure and enhance the release of thymol. As a result, thymol encapsulated in the modified yeast cells exhibited significantly enhanced storage stability and release profile, achieving > 5 log reduction of planktonic Listeria innocua cells > 6 log reduction of L. innocua cells in biofilms. These findings suggest that the combined effect of the targeted delivery, enhanced stability, and facilitated release of the thymol via encapsulation in yeast microcarriers present a promising strategy for controlling bacterial pathogens and their biofilms. Phenolic-rich antimicrobial extracts were obtained from different types of agricultural bioproducts (i.e. olive pomace and pomegranate pomace) using water-based ultrasound-assisted extraction (UAE). The aqueous olive pomace extract (OPE) or pomegranate pomace extract (PPE) exhibited strong antimicrobial activities against a broad range of plant pathogens. For example, based on the in vitro germination tube assay, OPE (≥ 1.0 mg GAE/mL) and PPE (≥ 0.5 mg GAE/mL) significantly inhibited the germination of Alternaria alternata conidia. In addition, based on the in vivo infection assay, OPE (≥ 0.5 mg GAE/mL) significantly suppressed the spread of Erysiphe necator infection (grapevine powdery mildew) on grape leaves. These findings highlight the potential of agricultural byproduct-derived extracts as effective and sustainable biopesticides. Ongoing research will apply these techniques in greenhouse and field trials to validate their performance under practical conditions. Additional formulations will also be explored to further enhance the stability and effectiveness of biopesticides.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Kim, Y., Wang, S. C., & Nitin, N. (2024). Development of a Sustainable Antifungal System Using a Synergistic Treatment of Aqueous Olive Pomace Extract (OPE) and Sunlight to Control Alternaria Infection on Tomato Plants. IAFP 2024, Long Beach, CA, USA. July 14  17, 2024.
  • Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Liu, S., Quek, S., Huang, K. (2024) An ecofriendly nature-inspired microcarrier for enhancing delivery, stability, and biocidal efficacy of phage-based biopesticides. Small, 2403465.
  • Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Kim, Y., Rai, R., & Nitin, N. (2024). Inactivation of Listerial biofilm on the food-contact surface using thymol and bio-modulated yeast microcarriers. Food Control, 110743.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Huang, K. (2024) Bio-inspired carrier systems for enhanced delivery of bacteriophages. Conference of Food Engineering, Seattle, Washington, USA, August 25-28, 2024.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Huang, K. (2024) Surface engineering of biobased microcarriers for enhancing agrochemical delivery and minimizing spray loss. ASABE Annual International Meeting, Anaheim, CA, USA, July 28  31, 2024.