Kimberly, Idaho — University of Idaho entomology doctoral student Kelie Yoho’s research suggests mineral oils could offer an environmentally friendly tool to help potato seed growers avoid losses to one of their most feared crop diseases, potato virus Y (PVY).
U of I master’s student Nathan Gelles has studied promising methods to promote sprouting in freshly harvested potatoes. His research could one day provide a new method for the Idaho Crop Improvement Association (ICIA) to induce sprouting of dormant seed tubers planted in test plots for PVY evaluation as part of the seed certification process.
Their efforts to tackle some of the most pressing challenges facing the potato industry haven’t gone unnoticed. Both U of I graduate students were recently awarded scholarships available to benefit the next generation of potato researchers.
Yoho, a third-year Ph.D. student from Twin Falls, earned $2,300 toward her education by winning the John L, and Lois K. Toevs Fellowship, which is awarded annually to a full-time student and gives preference to graduate research in potatoes or agronomy conducted at the U of I’s Aberdeen, Kimberly or Parma Research and Extension Centers.
Working in Kimberly under advisor Erik Wenninger, who is a UI Extension entomologist, Yoho and her team have been testing different combinations of treatments involving mineral oils and insecticides, also evaluating how well mineral oils withstand overhead irrigation.
Feeding aphids can pick up PVY from one plant and instantly spread it to the next plant before insecticides have time to take effect.
“Nobody really knows for sure, but the prevailing theory is mineral oils are interfering with the virus attaching itself to the aphid’s mouthparts,” Yoho said.
Research suggests insecticides alone may actually cause PVY to flare up by killing beneficial insects that prey upon aphids. Mineral oils don’t appear to harm beneficial insects. However, applications of mineral oils alone and mineral oils in combination with insecticides were both equally effective against aphids in trials. That’s significant because seed potato farmers use insecticides to control other pests and diseases.
Yoho and her team are also researching age-related PVY resistance of plants and monitoring aphid migrations to determine when mineral oil applications would be most effective. Furthermore, they’re studying the effects of their various treatment protocols on beneficial insects.
“I don’t think mineral oils are going to be the silver bullet that some people were hoping it would be, but incorporated into an integrated pest management program it seems like this is going to be a great help to reduce rates,” said Yoho, who hopes to one day teach at a university.
Gelles earned $1,100 through the Joe and Terri Guenthner Graduate Scholarship, an endowment honoring the career of Joe Guenthner, who was a U of I Extension economist for more than 33 years and remains active in the university as a professor emeritus. The scholarship is open to full-time graduate students in the College of Agriculture and Life Sciences who wish to pursue a career in the potato industry.
Gelles, who was raised on a Pingree farm, worked as a crop consultant for a while after graduating from U of I with a bachelor’s in crop management. He chose to return to school to pursue a master’s in plant science and has been working from the Kimberly Research and Extension Center under Nora Olsen, who is a UI Extension potato specialist.
“As a crop consultant there were more questions than answers, and I figured I could start answering some of those questions,” Gelles said.
In his research, Gelles has had success in using wood smoke to induce tuber sprouting soon after harvest. Wood smoke could be a tool for ICIA to break tuber dormancy when evaluating sprouted potatoes for PVY in a lab setting or prior to planting them in winter PVY test plots in Hawaii to base crop certification decisions.
“When you burn plant-based pellets, smoke releases hormones,” Gelles said. “There are a lot of species that require fire and smoke and heat to regenerate.”
This year, he’ll test the combination of smoke and another hormone to further expedite sprouting. Gelles is also involved in research on the effects of PVY on potato yields at the field level and on the distribution of PVY in different seed and tuber sizes. Only 2- to 4-ounce tubers are planted in the ICA’s winter test plots, and Gelles will research if the program may be inadvertently selecting for higher or lower levels of PVY based on its seed sizes.
A call for applicants for both scholarships goes out in the spring. Typically five to 10 students apply for each of the two scholarships.
“The thing that stuck out to me about these students was the immediate applicability of their research results,” said Mike Thornton, a U of I plant sciences professor at the Parma Research and Extension Center, who heads the committee that awards both potato scholarships. “Both of these were very applied projects with immediate potential benefits to the industry.
“We’re sending graduates out into the workforce that are prepared and educated and the potato industry can take them on right away and fill key positions in their companies.”