The Allium Leaf Miner is native to Europe, but was discovered in Pennsylvania in 2015. It is a fly whose larvae feed on crops of the Allium genus, including onions, garlic, and leeks.
Since arriving in the United States, it has spread to New York, Connecticut, Massachusetts, Maryland, and New Jersey and is considered a major agricultural threat. A team of researchers led by Cornell conducted field tests on 14 active ingredients in pesticides and applied them in a variety of ways to understand the best treatment options.
The researchers’ findings were described in a study published on June 13 in the “Journal of Economic Entomology” titled “The Digger for Management of Alliums: Emerging Diseases and Pests of Allium Crops in North America.”
A research team led by senior author Brian Nault, a professor of entomology at Cornell Agricultural Technology, and one of the leading Allium leaf insect management experts in the United States, discovered several traditional chemical pesticides It has the best effect on invasive insects.
Nault said: “On organic farms that do not use efficient management tools-synthetic pesticides-the problem of allium foliaricides is often more serious.”
Phytomyza Gymnostoma (Phytomyza Gymnostoma) has two generations a year, and adults appear in April and mid-September. In summer, most onions grow, and there is a pause between these two cycles, which allows the crop to escape the pests. Similarly, onion bulbs swell rapidly, which makes the leafer’s time unable to effectively forage.
Among adult miners, crops with green leaves are most threatened. In the northeastern United States, spring includes leeks, scallions and garlic, and autumn includes scallions and leeks. Wild alliums that span two generations can become reservoirs for insect growth.
The larvae begin to forage on the top of the plant and migrate to the base to turn up. Larvae can destroy blood vessel tissues, causing bacterial or fungal infections and causing rot.
The research team tested various management strategies with onions, leeks and green onions in Pennsylvania and New York in 2018 and 2019. Spraying chemical insecticides (dimethylfuran, cyanocyanoacrylonitrile and spinosyn) is the most consistent and effective method, reducing damage by up to 89% and eradicating insects up to 95%. Dichlorofuran and cyanocyanoacrylonitrile applied by drip irrigation technique are ineffective.
Other pesticides (abamectin, paracetamol, cypromazine, imidacloprid, lambda cyhalothrin, methomyl and spinosyn) also reduced the density of allium foliaricides. Spinosyn is applied to bare roots or plugs for plant activation, reducing the damage of insects after transplantation by 90%.
Although allium onion diggers have not yet become a problem with onions so far, researchers and farmers worry that they might become a problem if they gain traction and migrate west (which is the main crop of onions). Nat said: “This has always been a huge problem for the American onion industry.”