Most hop production in the United States is concentrated in the Pacific Northwest, particularly in Washington, Oregon and Idaho. However, in recent years, hops have expanded into other areas of the country, leading to farms in nearly every corner of the United States. The recent growth in the craft beer industry has led to elevated demands for locally sourced ingredients grown in unique and local environments. This trend has created increased interest in local hop production. In Nebraska, hops have emerged as a minor specialty crop, showing promising potential for local production and contributing to the state's diverse agricultural landscape.

Managing weeds in a hop yard is complex, given the diversity of annual and perennial weeds, limited herbicide options and labor-intensive mechanical control methods. Permanent trellis systems further complicate access to weed management and decision-making. Effective weed control in hops requires a combination of chemical, mechanical and cultural practices, all while maintaining soil health and preventing herbicide resistance. This article primarily focuses on herbicides labeled for use in hops production in Nebraska.

By integrating herbicide applications with other weed control practices, hops growers in Nebraska can maintain healthy crops and optimize yields. Effective weed management involves selecting suitable herbicides, applying them at the correct time, and adhering to safety and environmental guidelines. Beyond product choice, choosing the optimal application method for herbicides in hops is critical to achieving effective weed control while minimizing the impact on the crop and the environment.

The key to success lies in choosing the right equipment, timing and application parameters. Proper sprayer calibration is essential to ensure that herbicide distribution is even at the correct rate. Droplet size should be selected based on the herbicide label requirements. Generally, finer droplets improve coverage but are more prone to drift, while coarser droplets reduce drift but may result in reduced coverage, necessitating greater sprayer volumes.

Application timing relative to crops and weeds growth stage is also crucial for decision-making: (1) pre-emergence herbicides should be applied before weed seeds germinate before hops emergence, and (2) post-emergence herbicides should target weeds at their most vulnerable growth stages (2- to 4-inch height) after hops emergence.

Environmental conditions, such as wind speed, temperature and humidity, must be monitored to minimize drift and volatilization, reducing off-target impacts. Additionally, using best pest management (BPM) practices, such as rotating herbicides with different modes of action, strengthens long-term weed management strategies and helps preserve the effectiveness of herbicides over time.

This herbicide guide provides a comprehensive overview of the different herbicides suitable for hops in Nebraska, categorized by application timing and method. Always follow label instructions, local regulations, and best practices for safety and environmental stewardship.

Herbicide Categories by Application Window

1. Dormant Application

Herbicide application(s) when hops are not actively growing. This typically occurs in late fall after the harvest or early spring before bud break; ensure the treatment affects only the weeds and not the hops. The primary goal of these applications is to target seedlings after germination below the soil surface but before they emerge, thereby reducing weed competition during the active growing season.

2. Soil Applied

Herbicides are applied directly to the soil to control weeds before weeds and hops emerge (pre-emergence). Applying those herbicides creates a barrier at or below the soil surface, inhibiting the germination and growth of weed seeds. They prevent weed seeds from germinating or control them shortly after they germinate. Safety precautions — certain herbicides should be applied when the hop plants reach a specific age, as indicated on product labels.

3. Foliar Applied

Herbicides are applied directly to the leaves or stems of weeds. These herbicides can be either selective — targeting specific weed species while sparing the crop — or non-selective — controlling most plants they encounter. Foliar herbicides are typically used to control weeds that have already emerged and are actively growing. Use selective herbicides when hop plants and weeds coexist to avoid possible hop plant damage. Non-selective herbicides should not contact hop plant tissue (unless intended for mid-season defoliation) to prevent crop damage. Certain herbicides should be applied when the hops plants reach a specific age and height, as indicated on product labels.

4. Post-harvest

Post-harvest herbicides are applied after the hop harvest to control any remaining or emerging weeds and prepare the field for the next season.

5. Nursery (Foliar)

Foliar herbicides used in nurseries target weeds in young hop plants to ensure their healthy growth.

This list of herbicides registered for hops in Nebraska was gathered through the Nebraska Department of Agriculture and Crop Data Management Systems, Inc. (CDMS), last updated Aug. 18, 2024 (updated two times on an annual basis August and February). While other products within or outside this list are registered for weed control of hops in different states, applying products not registered in Nebraska is non-compliant. If unsure of a product's registration, visit NDA Pesticide Registrations or the CDMS database.

The pesticide applicator’s responsibility is to ensure that all products are registered for the intended use according to the product label. Always check the pesticide label and follow the instructions for the required or suggested application information. Be aware of any unique course of action (e.g., active ingredient maximum annual use, the addition of adjuvants, tank-mix with other pesticides, the restricted-entry interval (REI), personal protective equipment (PPE), etc., and pre-harvest intervals (PHI)) before application occurs.

Pesticide applicators must read and follow the applicable restrictions, limitations, and directions for use. They must follow the most restrictive directions for use and precautionary statements for each product when applied alone or in the tank mixture with other products.

For more resources about pesticide application technology, visit UNL’s Pesticide Application Technology Lab site or obtain the 2024 Guide for Weed, Disease, and Insect Management in Nebraska. For more information, please contact Milos Zaric.