“The biggest factor for onion farmers is preserving effectiveness,” said Brian Mortellaro ’95, who farms more than 200 acres in Elba, New York. “You can lose hundreds and hundreds of dollars an acre if thrips get out of control.”
Growing onions is a tough business; the crop is intensely managed on nutrient-rich soils found only in specific areas, and it’s beset by pests and pathogens. Winged onion thrips attack leaves, spread viruses and exacerbate bacterial and fungal rots. Insecticides are currently the most effective tactic for controlling them, yet thrips are notorious for developing resistance.
Enter Cornell entomologist Brian Nault, who spent a decade testing less toxic, more effective chemicals, which nearly all New York onion farmers now use. For years, though, most farmers were spraying on “calendar-based” schedules – applying pesticide at predetermined times – without knowing precisely when and if spraying was necessary. So Cornell experts set out to change that.
Nault, Ph.D. student Ashley Leach and longtime CCE vegetable extension specialist Christy Hoepting created and studied the effectiveness of an integrated pest management (IPM) implementation plan to increase growers’ use of insecticide application guidelines. Those guidelines include employing a rotation of insecticide sprays and action thresholds for when to spray, to prevent pests’ resistance and reduce spraying.
The study was supported by the New York Farm Viability Institute as well as an extension and outreach assistantship at Cornell AgriTech.