Strategies and methods to manage major insects and diseases of onion

Pests and diseases attack onions both in the field and in storage and reduce the yield and quality of onions. Improved management of pests and diseases are important to increase the marketable onions by reducing the waste during sorting. Onion fly and Fusarium basal rot represent major threats to sustainable Norwegian onion production and the project focuses on those organisms. The main objective of the project is to reduce yield and quality losses of onion through detection, monitoring, warning, and strategic control of onion fly and fusarium. The project will identify key Fusarium species associated with onion basal rot in Norway, identify the primary source of infection, develop molecular methods for the identification of onion fly, and detection and quantification of fusarium in onion and soil. We will evaluate the effect of selected low-risk fungicides, biostimulants, microbial biological control agents, basic substances, and chemical fungicides to combat the different Fusarium species infecting onions in Norway. Furthermore, we will develop a trap prototype for onion fly monitoring and optimize a German onion fly simulation model to fit Norwegian conditions. The project will contribute to the detection and management of fusarium in onion and the development of a monitoring and warning system for onion fly.

Onion fly and Fusarium basal rot represent major threats for sustainable Norwegian onion production. There are substantial gaps in our knowledge regarding these pests such as which Fusarium species infect onions in Norway, what are the main sources of Fusarium inoculum, and how onion fly prevalence is changing through the growing season. As the development of integrated pest management (IPM) strategies relies heavily on an understanding of pest biology, ecology, epidemiology, and environmental factors conducive to epidemic development, the knowledge gaps related to onion fly and Fusarium spp. hamper researchers’ and advisors’ ability to deliver sound and evidence-based IPM recommendations to both onion sets and food onion producers for the control of Fusarium basal rot and onion fly. By focusing on these knowledge gaps, the QualityOnion will develop new Fusarium detection and quantification methods, study how to combat the different Fusarium species infecting onions in Norway, develop a monitoring system and forecasting model for onion fly and study whether infestation by arthropod pests can predispose onion to Fusarium and vice versa. The QualityOnion will substantially improve our knowledge and understanding of Fusarium basal rot and onion fly. We hypothesize that improved knowledge of diagnostics, monitoring, forecasting, as well as interactions between fungal and arthropod pests, will improve the IPM strategies, and thus, help onion producers to reduce the yield losses related to onion fly and Fusarium basal rot. In addition, the QualityOnion contributes to reduced production costs and anti-resistance strategies by guiding the use of pesticides only where and when necessary. Altogether, the QualityOnion helps to extend the time that Norwegian onions are available on the market. By promoting profitability, food safety, and food security, the QualityOnion project will make a major contribution to sustainable onion production in Norway.