Onion Hi Keeper F1 Tiny Black Flies - Causes & Fixes

Jump to cause: Fungus Gnats (Sciaridae) Onion Maggot (Delia antiqua) Sapromyza (Fruit/Vegetable Flies)

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Fungus Gnats (Sciaridae)

The larvae of these flies live in the soil and feed on organic matter and fine root hairs, which can damage the developing bulb of the Hi Keeper onion. The adults emerge to lay eggs in the moist topsoil layer.

Very Common

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How to confirm: Set up a yellow sticky trap near the base of the onion plants to confirm adult presence.

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1 Deploy yellow sticky traps to capture adult flies and prevent further egg-laying in the soil.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

2 Reduce watering frequency and allow the top inch of soil to dry out completely to disrupt the larvae's moist habitat.

GROWIT Soil Moisture Meter SMM-V3

Water Meters

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3 Apply a biological control or organic insecticide to target the larvae and adults effectively.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

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Onion Maggot (Delia antiqua)

While primarily known for larvae, certain fly species are attracted to the moisture and sulfur compounds of Alliums. If the 'flies' are hovering specifically around the neck/base, they may be attempting to oviposit for maggot development.

Common

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How to confirm: Gently pull an onion plant to see if there are white, legless larvae tunneling near the bulb scales.

build How to fix it

shopping_cart Recommended Products

1 Apply an organic insecticide to eliminate adult flies and prevent further egg-laying near the onion base.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

2 Use yellow sticky traps to capture adult flies and monitor the infestation level around the plant necks.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

3 Ensure the soil is not overly moist and improve drainage to make the base of the onion less attractive for oviposition.

GROWIT Soil Moisture Meter SMM-V3

Water Meters

—

warning

Sapromyza (Fruit/Vegetable Flies)

If the onions have developed any soft spots or rot due to high humidity, these flies are attracted to the decaying organic matter produced by fungal pathogens.

Common

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How to confirm: Inspect the onion necks for any signs of softening, slime, or fermentation odors.

build How to fix it

shopping_cart Recommended Products

1 Inspect the onion bulbs for soft spots or rot and remove any decaying organic matter immediately to eliminate the flies' breeding source.

2 Apply an organic insecticide spray to control the adult flies and prevent further egg-laying on the plant.

Bonide Captain Jack's Neem Oil 32 oz

0.9 L • 1 pcs • Organic

$10

In Stock

3 Reduce humidity around the plants and ensure proper drainage to prevent the fungal decay that attracts these flies.