Asparagus Miner: Appearance, Territory, Damage and Life Cycle

Latin Name: Ophiomyia Simplex

Appearances: Adult asparagus miners can be found in the spring and late summer. They’re roughly 0.1-inch (2.5 mm) length, shiny black flies with a slight humpback. At the end of mining, dark brown, flattened pupae measuring up to 0.17 inch (4 mm) long can be observed beneath the epidermis.

Host Plants: This fly arrived in North America from Europe and can be found in areas where asparagus is grown. It solely eats asparagus and like to hang out on older stalks with ferns.

Territory: The asparagus miner was originally discovered along the northeast coast of the United States after being introduced from Europe. Every county in Michigan with commercial asparagus farming, including Mason, Oceana, Van Buren, and Allegan, has seen the asparagus miner.

Damage Caused: Adult flies do not harm the asparagus plant, but the larvae tunnel into the stem and bore mines into the cortex around the base. Because only a little portion of the plant’s stem is injured during mining, nutrient transmission is usually unaffected. Mining, on the other hand, is regarded a cosmetic harm that has an impact on the harvestable yield and marketing of asparagus. The larvae might encircle the stem in extreme cases. Asparagus miner damage has been linked to an increase in Fusarium crown and root rot, as well as an early decline in asparagus fields. Fusarium spores have been observed in abundance on the asparagus miner at all stages. The physical damage caused by miner oviposition holes and larvae tunnels is likely to let pathogenic Fusarium fungus to infiltrate the asparagus plant. Fusarium can reduce the economic lifespan of asparagus farms by 5 to 8 years if it is caught early.

Life Cycle and Habits: Asparagus miners overwinter as pupae in mined asparagus stem debris in Michigan. Each growing season in Michigan, two entire generations occur. Adult flies usually emerge in late May or early June, and their population peaks in mid-June. Adults mate soon after emerging, and females lay eggs towards the base of asparagus stems, either above or below the soil surface.  Females are drawn to asparagus plants in fern, which implies that early in the season, immature fields and volunteer asparagus are prone to egg-laying. Adults feed at the base of unopened asparagus blooms as well as areas where the asparagus beetle has caused damage. Around mid-August, when the fly’s mate, lay eggs, pupate, and overwinter, the second-generation adults are most plentiful.