How to control onion flies? A detailed guide to practical control methods

The onion fly, also called the onion maggot, is an oligophagous pest that only harms vegetables of the Liliaceae family, especially onions and garlic.

Controlling the onion fly should adopt a method combining agricultural control and chemical control. When garlic bulbs are rotting, a topdressing of ammonia water can be applied along with watering, which can significantly reduce the damage. When root maggots are found in the field, watering should be done frequently, and flood irrigation can be used when necessary.

Chemical control should combine aboveground and underground control, with adult flies controlled mainly aboveground. In the early stage of adult occurrence, you can use 80% dichlorvos emulsifiable concentrate at 800 times dilution, 5% beta-cypermethrin emulsifiable concentrate at 1500 times dilution, 2.5% deltamethrin emulsifiable concentrate at 2000 times dilution, and 2.5% cyhalothrin emulsifiable concentrate at 2000 times dilution, spraying them on the soil surface, root crowns and stems, once every 7-8 days, for two consecutive sprays.

In addition to spraying in the field, adult flies on nectar plants at the field edges should also be controlled. After larvae appear in the field, a chemical solution can be used to drench the roots. The pesticides used include: 40% isofenphos-methyl emulsifiable concentrate at 1000 times dilution, 50% phoxim emulsifiable concentrate at 1000 times dilution, 40% omethoate emulsifiable concentrate at 1000 times dilution, 80% dichlorvos emulsifiable concentrate at 800 times dilution, etc. When drenching the roots, the solution should penetrate at least 5 cm into the ground; where possible, the larger the application amount, the better the effect.