Jason Grauer, Cornell University
Myra Manning, Cornell University
Lindsay Wyatt, Cornell University
Watch this video at https://www.youtube.com/watch?v=pRvonR1lSsI
Organic growers are facing many challenges limiting their production of cucumbers, melons and squash. If you have ever tried to grow these crops in the eastern United States, you've probably had to deal with aphids, striped cucumber beetles, or downy mildew, but now there's hope. A NIFA-OREI grant known as ESOCuc, the Eastern Sustainable Organic Cucurbit Project, addresses these issues. ESOCuc is a collaboration of growers, extension agents, and university researchers working together to find solutions for you.
The ESOCuc project has four objectives:
- To evaluate the most popular varieties so growers can access updated information on yield and disease resistance
- To breed new varieties, guided by grower input, which will be made available through organic seed distributors
- To examine and improve management strategies to tell you what works against these pests and what doesn’t
- Finally, to make all this information readily available through online resources, webinars, and field days
For the past several decades, the seed industry has focused most of its attention on developing varieties for conventional farms. There has been little breeding specifically for the needs of organic farmers. It is clear that we must work directly with organic growers to solve this issue. As part of ESOCuc, we are evaluating popular cucurbit varieties to compare their performance in an organic environment, on research farms as well as collaborating organic production farms.
The Organic Variety Trial Database is currently available for finding information on potential variety choices. With our trials, we are looking to improve this resource to include precise measurements of varietal susceptibility to viruses, downy mildew, and striped cucumber beetles so that you can be well informed about what you are getting. Along with the trials run by Cornell Cooperative Extension in NY, Jeanine Davis is leading a set of evaluations at the Mountain Research Station in North Carolina and John Murphy is leading another set in Auburn, Alabama.
One focus of ESOCuc is controlling aphid-vectored viruses. When virus pressure increases in the early summer, growers may lose their whole crop. Even with the use OMRI-approved pesticides, aphids can still transmit viruses before the pesticide kills them. This has been an ongoing problem in the Southeast, but thanks to climate change, the Northeast may soon face these viruses as well. John Murphy of Auburn University and his team are developing a planting strategy that removes the virus from the aphids as they feed, reducing the risk of virus transmission into your fields. This strategy will be described on the eOrganic website and demonstrated at field days in Alabama.
Downy mildew is a wind-transmitted pathogen that affects all cucurbits. As you may already know, susceptible varieties can become completely defoliated within weeks of the disease arriving in the field. Cucurbit growers haven’t been overwhelmed by downy mildew for decades, but now new strains are on the rise. This new downy mildew has overcome previously resistant varieties and we need new strategies to combat it.
On the CDM-IpmPIPE disease prediction software, we can observe the disease patterns as downy mildew moves up the coast with tropical storms, and with winds from the west. CDM-IpmPIPE relies on reports from growers like you to track the movement of downy mildew. The more people use this resource, the more accurately users can anticipate the disease's arrival and determine when to start using OMRI-approved pesticides. Peter Ojiambo at North Carolina State University is working to make this system even better and more accurately forecast chemical control needs. We hope that you will become one of the growers that uses this resource.
In addition to evaluating varieties for resistance in the field, we will perform trials inside high tunnels to test drier environments that are less hospitable to the disease. You will have access to information about these control strategies as we pull together the data from management trials.
Striped cucumber beetles feed on the leaves, roots, and fruit of cucurbits—damaging plants and decreasing marketability. They can also spread bacterial wilt and squash mosaic virus between plants. The availability of systemic pesticides for conventional growers has really limited the investment in developing tools for organic systems. We’re working to close that gap.
In addition to looking at the economics of physical barriers like row covers, we’ll be providing enhanced trap-cropping strategies based on an understanding of what attracts beetles to cucurbits in the first place. We have noticed beetles have strong preferences for certain cultivars so we can direct breeding to incorporate low beetle preference. We will be able to accurately describe varietal susceptibility to beetle damage, making it easy for you to select the right strategy for your farm.
Popular cucurbit cultivars with consumer-desired characteristics often lack genetic resistance to pests. We’re working to develop cucumber, melon and squash cultivars that are open-pollinated, regionally adapted, tolerant to pests, flavorful, and prolific. A key to making this process work is grower input. We use surveys at meetings and conferences, needs assessments by the Organic Seed Alliance, and the direct feedback we get through on-farm evaluations of developing varieties. You can help guide this process by participating in these surveys to let us know what’s important to you. Outreach and extension are vital to this project’s success. All the work we’ve described is focused on grower needs, so success is dependent on our collaboration.
Our research will engage farmers and extension educators as active participants through on-farm trials, demonstrations, field days, workshops, and regional meetings. We encourage your continued feedback and even if you’re unable to attend one of these events, we hope you’ll find the information on cultivars, management strategies, and economics on eOrganic useful on your farm.
If you've seen cucurbit downy mildew on your farm, or are interested in learning how to recognize it, please consider participating in the CDM-IpmPIPE. The grower you help just might be yourself! To learn more about the ESOCuc project, visit the website or contact your local extension office for field day and meeting information. To receive updates on eOrganic/eXtension webinars relating to this research, sign up for the eOrganic newsletter at http://eOrganic.info.
- Cucumber Downy Mildew Forecast (CDM-IpmPIPE). Available at: http://cdm.ipmpipe.org/
- EsoCuc Website: Organic Cucurbit Research: Critical Pest Management Challenges. Available at: http://eOrganic.info/cucurbits
- Organic Variety Trial Database: Available at: http://varietytrials.eorganic.info/