Developing a degree-day model to improve asparagus miner (Diptera: Agromyzidae) management in Michigan

Globally, asparagus production is in decline due to increased pest pressure, despite increasing consumer demand. Michigan is the second largest producer of asparagus with 10,700 acres in commercial production in 2010. The asparagus miner, Ophiomyia simplex (Diptera: Agromyzidae) is an important pest because it is a potential vector of a serious disease, called Fusarium crown and root rot. Our research focuses on developing integrated pest management tools for asparagus growers, including the development of a degree-day model for the miner. First, we used laboratory bioassays to determine the lower developmental threshold of asparagus miner pupae. This information is necessary to predict first emergence of miner adults in the field. Subsequently, we validated important phenological events in the lifecycle of the miner by surveying population abundance at five commercial farms and correlating the data with information from weather stations placed at the farms. By relating temperature data with peak flight of adult miners, we can provide growers with information on when to apply selective insecticides against this life stage. Our results will help growers improve control timing of the asparagus miner. Overall, this will contribute to lowering pesticide use in asparagus, improving asparagus miner control and lengthening the life of commercial asparagus plantings.