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Allium Leaf Miner: A Threat to Allium Crops in the United States

Allium Leaf Miner
Top: An Allium leaf miner adult. Bottom: Allium leaf miner parasitoids. (Photos courtesy of Gaylord Desurmont)

The Allium leaf miner (ALM), native to Europe, is an economically important leaf-mining fly. It attacks many species in the onion family including leek, chives, onion, garlic, shallot and ornamental allium plants.

This species causes extensive damage to allium crops in an increasing number of European countries but also in the United States, where it was accidentally introduced and reported for the first time in 2015, in Pennsylvania and soon after in adjacent states including Connecticut, Maryland, Massachusetts, New Jersey and New York. It is expected to spread to other northeastern states.

While physical and chemical methods are available, these have proven to be only marginally successful. Therefore, European Biological Control Laboratory (EBCL), in partnership with collaborators in the United States and the Switzerland-based agency CABI have initiated the development of a classical biological control program.

An important first step in developing a biological control program for ALM is to develop new diagnostic molecular tools to determine the geographic origin(s) of ALM in the United States. Doing so will facilitate the collection of co-evolved parasitoids abroad that are highly specific for ALM populations and should provide growers with new self-sustaining biological agents for its control.

DNA Footprint of Allium Leaf Miner
DNA fingerprint of one ALM specimen. (Photo courtesy of Marie-Claude Bon)

Authors: Gaylord Desurmont and Marie-Claude Bon

Contact: Michael Grodowitz

The European Biological Control Laboratory (EBCL) was established in 1991 near Montpellier, France. EBCL was created by the merger of the former European Parasite Laboratory, established in Paris in 1919, and the Biological Control of Weeds Laboratory in Rome. EBCL has a satellite laboratory in Thessaloniki, Greece. As the only USDA ARS-operated laboratory outside the United States, EBCL develops biological control technologies which can be used to suppress invading weeds and insect pests of Eurasian origin. EBCL researchers do this by searching for natural enemies (insects, mites, and pathogens) in their native habitat, determining their identity, testing their host specificity and potential impact in laboratory and field experiments, and shipping promising organisms to the U.S. for further testing as biological control agents. EBCL collaborates with scientists in many countries in Europe, Asia, and Africa to explore in regions of origin of the target weeds and insects.