Biological control and degree-day modeling yield promising results for managing the asparagus miner (Diptera: Agromyzidae) in commercial asparagus fields

The asparagus miner is a stem-mining pest that can spread a fungal pathogen called Fusarium. This pathogen may reduce the lifespan of a commercial production field by 5-8 years. Research over the past four years has led to two promising methods of asparagus miner management: conservation biological control and the use of a degree-day model. Twelve species of hymenopteran parasitoid species were reared from asparagus miner pupae. Two of these comprise over 80% of the species assemblage and are potential targets for conservation biological. Flowers that may be planted in field borders to enhance parasitoids were tested to find out if adult asparagus miners are also able to use these as resources. Buckwheat and fava bean are two potential plants that may be used in the field, since these did not increase the lifespan of the asparagus miner. The degree-day model was developed by ascertaining the lower developmental threshold for asparagus miner pupae (the overwintering stage), and using temperature information from a local weather station. There is a good fit between predicted occurrences of phenological events and observed occurrences, indicating that the model is reliable. This model will be accessible by growers on Michigan State University’s Enviroweather network.