Project Overview
Commodities
- Additional Plants: herbs
- Miscellaneous: Peppermint
Practices
- Crop Production: application rate management, cropping systems
- Education and Training: extension, farmer to farmer, networking, on-farm/ranch research, participatory research, workshop
- Pest Management: biofumigation, soil solarization
- Production Systems: dryland farming
- Soil Management: soil microbiology, soil quality/health
Abstract:
Peppermint (cv. Black Mitcham) is a high-value crop grown for both its desirable oil composition and high yield. However, this crop is highly susceptible to Verticillium wilt, a devastating disease caused by Verticillium dahliae. While this perennial crop could traditionally be grown for five years, in recent years, mint stands have begun to decline after only three years, after which oil yields decline to such an extent that the crop needs to be replanted in another field. Growers are running out of suitable land that is free from Verticillium wilt. All mint cultivars grown commercially are sterile hybrids; therefore, traditional breeding for Verticillium wilt resistance has not been possible. Research to better understand the peppermint genome is underway, but breeding and releasing a resistant variety are still far away. Broad-scale fumigants can help suppress this disease but are prohibitively expensive. Moreover, these products can negatively affect beneficial soil microbes that provide key agroecosystem services.
This project worked closely with mint growers to evaluate their current cultural practices and design new production systems which integrate more holistic and sustainable practices. Midwestern mint growers were surveyed, and data was gathered to elicit farmers' decision-making processes, perceptions towards land availability, and technology adoptions. Participatory on-farm research trials were conducted to investigate the effect of biological approaches to remediate soils infested with V. dahliae. Approaches included a mustard cover crop and anaerobic soil disinfestation (ASD). A farmer-to-farmer education and outreach component included field days, workshops, online presentations with farmers, presentations at grower conferences and academic conferences, and a visit of Indiana growers to farms in Washington State and Oregon. Farmer experience guided the development of resource publications, which will be used across the state and the Midwestern United States. To increase farmer participation in this project, a farmer advisory committee was formed to guide research and outreach components. The farmer advisory committee included members of the Indiana Mint Market Development and Research Council (IMMDC).
Midwestern mint growers gained knowledge about alternative solutions for Verticillium wilt management. Knowledge gained from growers and research and outreach efforts translated into educational programs that were better equipped to fully support mint growers regionally to adopt enhanced sustainable agricultural practices.
The producer survey focused on management and cultural practices adopted to control Verticillium wilt. Findings from the survey highlighted the main practices in peppermint production among farmers in Indiana. The main findings include the age of the peppermint field, oil production (lb/acre), and planting strategies to prevent mint yield reductions due to pests. Efforts are underway to publish the results of this survey in an expert-reviewed Purdue Extension publication in 2023. The results of the greenhouse and field trials demonstrated that ASD has the potential to improve soils and contribute to an integrated management plan for the control of Verticillium wilt in mint. Further research is needed to identify the best substrates and rates to optimize ASD for controlling this devastating pathogen on the diverse types of soils that mint crops are grown on in the Midwestern U.S. However, researchers and growers are concerned about using tarps on a large scale. It is not sustainable and might not be financially viable. The use of ASD might only be feasible on a small scale, i.e., in a mint nursery. Further research into the economic aspects of ASD and the use of tarps needs to be conducted. The research further indicated that a mustard cover crop also has the potential to help suppress Verticillium wilt as part of an integrated management plan. However, further work is needed to optimize this practice as well. Several growers plan to incorporate a mustard cover crop in their rotation.
Project objectives:
The project will document current mint production practices to identify key factors contributing to Verticillium wilt and identify opportunities to integrate more sustainable approaches to ensure long-term profitability. The potential for anaerobic soil disinfestation (ASD) and cover crops to mediate Verticillium wilt cost-effectively will be determined. Mint growers will learn how to conduct on-farm research and share information through a farmer-to-farmer network to ensure that results are disseminated and adopted. Adopting improved production innovations recommended from this project should lead to longer crop cycles, enhanced soil health and maintenance, improved economic viability, and better farmland use.