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Optimizing management of cucumber downy mildew to currently used fungicides

Research Scholar

Ana Cristina Arciniega, OARDC - Plant Pathology (Ecuador)
Sally Miller, Faculty Mentor


Ana Arciniega was born in Quito, Ecuador in 1990. She earned her bachelor's degree in 2010 from Zamorano University, Honduras, conducting a thesis project titled "Evaluation of citric and lactic acid in Mozzarella cheese production." In 2010 she performed research in the Soil and Crop Sciences Department at Texas A&M University, where she studied extrusion and food product development. Arciniega has been a visiting scholar at The Ohio State University since 2011, performing food safety research in watershed and vegetable production in the School of Environment and Natural Resources and the Department of Plant Pathology.

What is the issue or problem addressed in your research?

Downy mildew is a potentially devastating disease caused by the pathogen Pseudoperonospora cubensis that was not reported in Ohio cucurbit fields until late August or September, being dependent on remnants of seasonal winds to carry the spores northward without considerable affect on yield. However, since 2004, this disease appeared much earlier causing extensive defoliation; furthermore, economical expenses in fungicides application are significantly increased for disease control. The objective of this research project is to evaluate the relative sensitivity of downy mildew pathogen to commonly used fungicides.

What methodology did you use in your research?

The project combined a greenhouse experiment planting cucumber in pots with an exposition to infected cucumbers in field. Cucumber seedlings were grown individually in pots inside greenhouse to the 2-4 leaf stage, then four replicate plants each was sprayed with one of the 7 fungicides treatments at field use rates, keeping an extra plant as a control. Plants were allowed to dry overnight, and then placed in cucumber fields in three locations in Northern Ohio (Wooster, Celeryville and Fremont). Plants remained in the field for 24 hours, and then returned to greenhouse. Plants were scouted daily for downy mildew and to monitor severity through growing season. Finally after 6 and 14 days, cucumbers lesions were evaluated using a visual scale from 0 to 100%. Field and laboratory data were analyzed using SAS statistical software.

What are the purpose/rationale and implications of your research?

The present study wants to transcend main goal and provide conventional growers in Ohio with a ranking of product efficacy and a development of an effective Integrated Pest Management approach considering economic risks and benefits of reduced sprays or grow disease resistant varieties of cucumbers. Therefore, this optimized management directions will assist cucumber growers to reduce yield losses and expenses in fungicides.