Project Overview

Reports

Commodities

• Additional Plants: hemp

Target Pests

• Target Pests: lepidoptera

Practices

• Pest Management: biological control, decision support system, monitoring/scouting

Corn earworm, Helicoverpa zea, is a cosmopolitan, highly polyphagous, and injurious insect to a wide range of agricultural crops throughout the continental United States (Reay-Jones 2019). This insect has turned out to be one of the most important pests of outdoor grown hemp in all places where production occurs (Britt et al. 2021) and successful management strategies have yet to be cemented. Larval feeding damages flower buds, the marketable portion of cannabinoid type hemp, and can lead to significant economic loss to hemp flower bud and biomass yields. Monitoring is an important aspect to managing this pest, but little guidance exists as to inform current best management practices. Methods are sorely needed to inform appropriate monitoring strategies for corn earworm in hemp – many growers implement some form of pest management for this insect, but better timing and knowledge for successful strategies for pest intervention is key for protecting hemp growers’ investments in their crop. As hemp was recently re-legalized as an agricultural commodity in the United States, there is a dearth of knowledge on all aspects of this crop, including production and pest management. This project will apply our understanding of the existing corn earworm pheromone trapping program in other agricultural commodities to improve scouting and economic threshold method development for hemp as well as understanding the roles of natural enemies in corn earworm pest management in hemp by conducting field surveys.

To obtain information for this key issue in hemp, we will employ the following objectives:

1) Evaluate the relationships of corn earworm moths caught in pheromone-baited traps to corn earworm egg and larval populations on plants and to flower yield loss throughout the growing season.

2) Survey natural enemies of corn earworm eggs and larvae and determine their presence and natural role in aiding management of corn earworm populations.

3) Develop corn earworm monitoring and scouting method video tutorials to improve grower capacity to manage pest issues on farms and disseminate project results to grower stakeholders at meetings and field days.

The goal of this Western IPM Initiation Project is to gather baseline data so that corn earworm pest management strategies can be improved in field grown hemp in the Western region. Specific project objectives include:

1) Evaluate the relationships of corn earworm moths caught in pheromone-baited traps to corn earworm egg and larval populations on plants and to flower yield loss throughout the growing season.

2) Survey natural enemies of corn earworm eggs and larvae and determine their presence and natural role in aiding management of corn earworm populations.

3) Develop corn earworm monitoring and scouting method video tutorials to improve grower capacity to manage pest issues on farms and disseminate project results to grower stakeholders at meetings and field days.

Our proposed research objectives clearly fit with priority documents of the Western IPM Center and the National Roadmap for IPM. The project is timely for several reasons: it utilizes existing technical expertise present in the Western region and expands on resources to improve knowledge to direct future hemp corn earworm IPM research and extension efforts in the western region. Also, the direct engagement of hemp growers and stakeholders in Oregon and California will aid in long-term solutions for corn earworm pest management issues.