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

Outputs
Target Audience:The primary audience for this research includes agricultural science professionals and potato industry stakeholders. The potato industry was specifically targeted because plant-parasitic nematodes pose a major challenge in potato production systems. Stakeholders expressed strong interest in learning about new tools to combat nematodes. We have shared our findings with this audience mainly through presentations at potato field days and annual scientific meetings such as Potato Association of America, Society of Nematologist. Specific conferences that targeted producer education included Idaho Association of Plant Protection, the University of Idaho Research and Extension Potato Conference, and the Washington-Oregon Potato Conference. In addition, undergraduate students have engaged with the research by working alongside graduate students and postdoctoral researchers through lab internships and hourly positions. Graduate students from three different universities collaborated on research projects, strengthening their research and scientific understanding. These informal training opportunities not only introduce students to the latest techniques in plant science but also encourage future careers in agriculture. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided training to a total of two personnel in the Gleason lab. It partially supported a Master's student, Koy Chandler, who graduated in May 2025. The funds also supported a post-doc, Sean Mccotter. The training included practicing and improving different scientific techniques and presenting results and data to the department. Koy Chandler spoke about his work with the alginate beads at the American Phytopathological Soceity Pacific Division conference. The audience included scientists from the western USA. The project provided training to a total of three personnel in the Dandurand lab. It supported a PhD student and Research Associate Lindsay Schulz, who is scheduled to graduate May 2026. She spoke about her research to producers at Idaho Association of Plant Protection in November 2024 and to scientists at Society of Nematologists conference in July 2025. She has done training with Pia Spychalla, a graduate student at Cornell University, New York. Lindsay has also helped train two research aides and three undergraduate students partially supported by this research. How have the results been disseminated to communities of interest?PhD student Lindsay Schulz presented her work to students at Minico High School August 2025 as part of a Solanum sisymbriifolium outreach and education effort. What do you plan to do during the next reporting period to accomplish the goals?The goals for the next reporting period will be to continue refining the aliginate bead formulations by testing the beads with different nematodes, including cyst nematodes. Field trials for alginate bead protection of potato against root-knot nematodes are planned for spring 2026 to assess performance under real-world conditions. The S. sisymbriifolium infused pots will undergo further optimization, and if the pots look promising, we will expand the trials to grape plants to evaluate for protection against the root-knot nematode M. hapla. Identification of Solanum sisymbriifolium root volatiles will take place. Additionally, S. sisymbriifolium amendment experiments will be tested again with older plant material to see if we can optimize the effect that the organic material is having on G. pallida with the toxins from the plant. Lastly, with a better understanding of which formulations effectively protect plants againts nematodes, the project economist will conduct cost-benefit analyses to evaluate the economic feasibility of adopting the new products on farms.

Impacts
What was accomplished under these goals? Plant parasitic nematodes are roundworms that attack plant roots and cause billions of dollars in agronomic losses each year. Root-knot nematodes and cyst nematodes are the two most damaging nematodes on many crops, and are especially problematic on potatoes. Growers traditionally use synthetic chemical pesticides for nematode management, but many of these chemical controls have been banned or are very expensive for growers to use. This has created an urgent need for safe, sustainable, and effective alternatives. To meet this need, we have focused our research on the trap crop called Solanum sisymbriifolium. We are exploring different ways to turn this plant into a biopesticide. As part of this proejct, we have studied incorporating its biomass into the soil, using slow-release alginate beads, and using a biodegradable pot coated in S. sysimbriifolium powder. Through these advances, we are moving closer to an environmentally friendly, plant-based biopesticide that could reduce farmers' reliance on synthetic chemicals while protecting crops from destructive nematodes. One of the key acccomplishments in the last reporting period has been soil incorporation trials. Freeze-dried S. sisymbriifolium (litchi tomato) mixed into soils with potato plants and exposed to root-knot or cyst nematodes. There was no significant difference between amendment rates and material that was leached of chemcials. However, there was a significant difference between all treatments and the control. Since treatments that were leached from chemicals still showed significant reduction in nematode infection it is predicted that the amount of organic matter added to the soil is causing the reduction in infection instead of the toxins found within the plant, but this remains to be further studied. While there was no significant nematode control at the tested rates, the approach may still improve soil health by adding organic matter. Further testing will be performed using older plant material and plant material that was processed in different ways. Another major accomplishment was the chemical analysis of S. sisymbriifolium by GC/MS. The analysis confirmed that there is high glycoalkaloid content in S. sisymbriifolium. Glycoalkaloids are compounds known to be toxic to nematodes. Although the S. sisymbriifolium contains toxic glycoalkaloids, the effects may have been diluted when the S. sisymbriifolium was incorporated into the soil. Based on these results, the research shifted from direct soil incorporation to controlled-release delivery methods (alginate beads, coated pots) to concentrate active compounds and enhance nematicidal efficacy. The next major accomplishment was the development and testing of alginate bead biopesticide formulations. A 5% w/v freeze-dried S. sisymbriifolium (above ground stems and leaves) was added to an alginate solution to create alginate beads. These beads were added as a layer to a cone-tainer with a tomato seedling, and inoculated with root-knot nematode eggs. The alginate beads containing freeze-dried S. sisymbriifolium did not affect plant growth and provided significant plant protection from nematodes, reducing root galling 50-90%. The fourth major accomplishment in the reports period was the development of compostable pots that were infused with S. sisymbriifolium. The pots were coated with freeze-dried S. sisymbriifolium (stem and leaf material) on the inside of the pots. Early tests show no negative effects on plant growth, and nematode suppression trials are in progress. The last major accomplishment in the report period was the discovery that volatiles released from S. sisymbriifolium roots significantly reduced hatch and viability of Globodera pallida. This research is ongoing and volatile compounds from S. sisymbriifolium roots are being analyzed with GS/MS. This is a promising source of biopesticide formulation. Our research on new biopesticide formulations is ongoing, but the work is showing potential for a new tool in nematode management, potentially saving growers money and reducing exposure to synthetic chemical controls.

Publications