NY Onion Growers Can Decrease Chemical Use According to New Research

New York State has a high potential for onion production, with proximity to markets on the east coast and a large national demand for storage onions, when disease and pests don’t interfere. Nearly all of New York’s onions are grown in the state’s fertile Muck soils and require a reliance on cultivation, fertilizer, and pesticides in this climate. However, new research has shown that NYS onion growers are likely able to decrease use of insecticides and fertilizers without seeing reductions in yields.  

A recent study conducted by Cornell AgriTech showed that farmers are able to decrease insecticide applications for onion thrips while maintaining yields by following action thresholds. Action thresholds help farmers determine when to apply insecticide based on pest population density. Action thresholds indicate when a pest population reaches a density that requires a control measure in order to prevent the population from causing economic harm.  

Brian Nault, a professor of entomology at Cornell AgriTech, has been studying onion thrips (small, winged insects that feed on and infect onion plants) for many years. He has observed an increase in insecticide resistance in the insect since the 1990s. By using action thresholds to decrease insecticide applications, farmers can mitigate insect resistance. Nault’s hope is that growers will move away from traditional weekly spray programs and adopt the use of action thresholds.  

NYS onion growers interested in adapting an action threshold program can learn more about implementing this strategy at Cornell Cooperative Extension. The thrips threshold that was used for this study was one thrips per leaf. This method requires field scouting on a weekly basis. 

The study also demonstrated that farmers are able to use 50-100% less fertilizer without a decrease in yield. The study showed that decreased fertilizer use had no impact on thrips population levels, bulb rot, bulb size, or yield. A reduction in fertilizer use will have many economic and environmental benefits to farmers, especially for soil and water health. 

Max Torrey’s family farm in Elba, NY, was a trail site for study. “Plots with no fertilizer had no difference [compared to plots with full and half amounts],” Torrey told Cornell Chronicle.  He noted that scouting for thrips and collecting soil samples requires more work, but he estimates that he will ultimately save at least $100 per acre in chemical costs on his 2,200 acres of onions, in addition to the environmental benefits.

These findings will help farmers to reduce costs and make New York onion growers more sustainable and competitive. Nault estimates that if all New York onion grows used action thresholds they would see a cumulative annual savings of $420,000 in pesticide costs. 

Read more about decreasing chemical inputs and using integrated pest management (IPM) practices in onion production at Cornell Chronicle and Cornell Small Farms

Avery MacLean

Avery is a senior in CALS majoring in Agricultural Sciences. Avery’s interest in agriculture began when she started raising laying hens and selling eggs in middle school. In 2021, Avery founded Red Wing Farm, a small market garden located on Grindstone Island in northern New York. After her experience managing a farm, Avery is excited to be learning more about sustainable management practices for small farms in New York State. When she’s not studying or in her garden, Avery loves to spend time working on fiber arts, walking her dog, or cross-country skiing in her hometown in southern Vermont.
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