Source: OREGON STATE UNIVERSITY submitted to NRP
BEYOND CHEMICALS: ELECTRICITY AS AN ALTERNATIVE FOR WEED AND DISEASE MANAGEMENT IN HOPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
Reporting Frequency
Annual
Accession No.
1032683
Grant No.
2024-70006-42858
Cumulative Award Amt.
$324,999.00
Proposal No.
2024-03515
Multistate No.
(N/A)
Project Start Date
Sep 1, 2024
Project End Date
Aug 31, 2027
Grant Year
2024
Program Code
[ARDP]- Applied Research and Development Program
Recipient Organization
OREGON STATE UNIVERSITY
(N/A)
CORVALLIS,OR 97331
Performing Department
(N/A)
Non Technical Summary
The United States is a top producer of hops globally but grapples with considerable challenges in disease and weed management while striving to reduce pesticide residues, which can be barriers to export markets. Powdery and downy mildew are prominent among these challenges. Current practices involve early-season crop growth removal through herbicides or mechanical means to diminish primary disease sources, followed by a stringent in-season fungicide regimen. Although mechanical pruning aids in disease suppression, it disrupts soil structure, fosters weed germination, is costly, and may have unintended environmental consequences. Our project aims to evaluate electricity's efficacy, safety, quality, and economic viability for weed and disease management in hop cultivation. In collaboration with growers from Washington, Oregon, and New York, we will conduct field experiments targeting three primary objectives: (i) Assessing the impact of foliar-applied electricity on disease and weed densities, herbicide and fungicide use, and hop maturation; (ii) Formulating guidelines for electricity application during early-season shoot growth; (iii) Investigating electrotherapy's potential in hops by determining sublethal electricity doses for powdery and downy mildew control. Anticipated outcomes include decreased reliance on fungicides and herbicides and improved soil health through reduced tillage. The holistic approach of our research aligns with the overarching objective of fostering sustainable and efficient practices within the hop industry.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2162230114070%
2164020116030%
Goals / Objectives
The overarching objective of this project is to pioneer electricity as an eco-friendly alternative to pesticides for weed and disease management, ensuring both ecological prudence and human safety. We aim to evaluate the viability of integrating these innovative technologies into hop production systems to ensure affordability and environmental sustainability. By introducing novel Plant Protection Tools and Tactics, we aim to enrich the diversity of weed and disease management strategies. The project team and farmer collaborators will guide our outreach efforts, targeting a broad audience through interactions with hop grower networks. We will assess the effectiveness of all extension products and activities, focusing on fostering conservation and enhancing environmental outcomes associated with hop production.
Project Methods
Our approach includes three interconnected activities: experiment station research (Obj 1), a series of replicated studies on commercial farms to evaluate the effects of different rates of electricity applied to hop basal foliage during the summer to control powdery mildew and weeds. (Obj 2), field studies conducted during hop emergence to assess the interaction of electricity interacts with downy mildew and its impact on crop emergence, and (Obj 3), we will explore the use of sublethal rates of electricity to suppress powdery mildew without affecting hop growth. Obj 1: We will select commercially relevant hop varieties such as 'CTZ that are sensitive to powdery mildew. Studies will be organized as a two-factor design with basal foliage removal method and time of last fungicide application as factors. Basal foliage removal will include the herbicide carfentrazone 35 g ai ha-1 or electricity (2 km h-1). Each treatment will be applied once or twice between July and August. Overlaid with the basal foliage treatments, we will include two levels of fungicide treatment (i) fungicide applications made up to late July, or the end of the period of greatest host susceptibility to powdery mildew and (ii) fungicide applications made up to late August, a typical grower standard. Obj 2. This objective aims to document whether electricity can reduce disease and weed pressure.In a commercial hopyard. the following treatments will be compared: 1) mechanical pruning, 2) chemical pruning (carfentrazone), 3) chemical removal (carfentrazone) applied twice, 4) electricity applied once 5) electricity applied twice, and 6) nontreated check. Treatments will be applied in early April, and reapplied, if indicated, 10 to 14 days later. The experiment will be designed as a randomized complete block with at least four replicates. Each replicate will consist of ten plants. Obj 3. Our studies will be conducted on a University farm to evaluate the effect of low electricity rates on hops. We will evaluate treatments at 3.5 MJ ha-1 to as low as 0.5 MJ ha-1 to identify the highest energy level that does not effect hop growth or injure foliage. Foliar injury will be monitored visually and non-destructively by chlorophyll leaf content as assessed by chlorophyll fluorescence. We will determine the affect of electricity applied pre- or post-infection with powdery mildew. Based on surveys, powdery mildew is of widespread importance to the industry. Greenhouse-grown hop plants will be disease-free until early spring, when weather conditions are conducive for powdery mildew infection. Plants will be inoculated with a field-population Podosphaera macularis solution. Two sublethal energy levels identified by the initial study will be applied at 7, 3, and 1 days before and 1, 3, and 7 days after inoculation. A fungicide and an untreated control will be included as a reference at all application times. The study will be organized as a two-factor factorial with four disease control treatments, six treatment times, and a noninfected, nontreated reference. Four plants per treatment will used. The study will be repeated.

Progress 09/01/24 to 08/31/25

Outputs
Target Audience: Oregon hop growers Washington Hop growers Hop growers in the NE United States Changes/Problems:The performance of the electric equipment for objective 1 was not ideal because the electricity could be applied only in limited locations so as not to damage the hop shoots which are supported by strings tied to an overhead trellis system. We could not adequately treat the targeted area compared with the herbicide application. We are considering changing the method or timing to circumvent this problem. Drought conditions have impacted hop growth and development in the Northeastern US. What opportunities for training and professional development has the project provided?One PhD student and one undergraduate student have been training in the operation of equipment, experimental design, implementation, and equipment maintenance. We developed a method for weed science assessments. Individualized training on cultural control measures for disease was conducted with cooperating growers during planning and conduct of on-farm trials. Training was provided to one PhD student and one undergraduate student on basic methods in field plant pathology through experiential learning and hands-on training. How have the results been disseminated to communities of interest?Research updates to industry stakeholders in the Pacific Northwest. As we are collecting data from the first year of the study, only collaborators and cooperators have access to results.. Alluri, Greeshmanth. Weed and Disease management with electric weed control - results in hops. Seminar presentation at OSU. May 2025. What do you plan to do during the next reporting period to accomplish the goals?Cornell: We will evaluate and analyze data from year 1 trials in and conduct the second year trial. Oregon State: In 2025, we will continue the spring pruning studies and will likely expand to a second site. Experiments that were begun in Spring 2025 will continue to be evaluated for disease and harvested. We will initiate the objective 3 study and have formal data analysis and presentation at regional meetings and extension meetings. Extension outreach presentations will be made to growers and other industry professionals in fall 2025 and winter 2026. Planning and implementation of 2026 experiments will be conducted.

Impacts
What was accomplished under these goals? Objective 1: Trials have been established; data is being collected. A large field experiment is in place with a cooperating grower in Washington State: A 3.5 acre field study is ongoing on a commercial farm in Toppenish, WA. The experiments compare the effect of electricity for removal of excessive foliage and canopy management for disease and weed control. Data collection is in progress as proposed. Objective 2: Experiments were planned and implemented to evaluate the impact of electricity for early spring management of hop shoot growth, suppression of the disease downy mildew, and weed management. A large experiment was begun in April 2025 with a cooperating grower in Oregon. Measurements of downy mildew were made biweekly from early April to present to quantify how changes in early season vegetation management influence seasonal progression of the disease. Initial results indicated that electricity did not suppress downy mildew. Data collection is ongoing.This study is nearing completion. Electricity successfully removed weeds and hop shoots in early spring. Weed control with electricity was significantly superior to the current industry standard. The field will be harvested in September 2025. Objective 3: Experiments were planned to evaluate the impact of sublethal doses of electricity on perennation of the priority disease issues of hop.Trials have been established; data is being collected. A handheld applicator was purchased and delivered. We will initiate testing in the fall of 2025. We obtained plants from a commercial propagator and are growing them in an isolated area to avoid disease contamination. We will carry out this experiment on the proposed timeline.

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