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Hosta sieboldiana Frances Williams Tiny Black Flies
eco Tiny Black Flies

Hosta sieboldiana Frances Williams – Tiny Black Flies

Why does your Hosta sieboldiana Frances Williams have tiny black flies? Diagnose the cause and fix it with our step-by-step guide.

yard View full Hosta sieboldiana Frances Williams care guide
Jump to cause: Fungus Gnats Sciarid Flies Blackberry Leaf Spittlebug (or similar Hemiptera)

search Possible Causes

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Fungus Gnats

These tiny black flies thrive in the moist, organic-rich soil that 'Frances Williams' requires. Their larvae feed on fine feeder roots and decaying organic matter within the hosta's pot or garden bed.

Very Common
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How to confirm: Set up a yellow sticky trap near the base of the plant to see if small winged insects are captured.
build How to fix it
shopping_cart Recommended Products
1 Deploy yellow sticky traps to capture the adult flying gnats and interrupt their breeding cycle.
Super Ninja Fungus Gnat Traps - 30 Pack
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 kill larvae in the moist substrate.
GROWIT Soil Moisture Meter - Blue
GROWIT Soil Moisture Meter - Blue
Water Meters
$12
In Stock
3 Apply a biological control or organic insecticide to target the larvae living in the organic matter.
Bonide Captain Jack's Deadbug Brew 16 oz
Bonide Captain Jack's Deadbug Brew 16 oz
0.5 L • Organic
$15
In Stock
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Sciarid Flies

Similar to fungus gnats, these flies frequent overly saturated Hosta soil. They are often a symptom of poor drainage or a watering schedule that keeps the top layer of mulch or soil constantly damp.

Common
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How to confirm: Check if the soil surface remains wet for extended periods after watering.
build How to fix it
shopping_cart Recommended Products
1 Reduce watering frequency and allow the top inch of soil to dry out completely to disrupt the life cycle of the flies.
GROWIT Soil Moisture Meter SMM-V3
GROWIT Soil Moisture Meter SMM-V3
Water Meters
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2 Deploy yellow sticky traps to capture the adult flies and prevent further breeding in the soil.
Super Ninja Fungus Gnat Traps - 30 Pack
Super Ninja Fungus Gnat Traps - 30 Pack
30 pcs
$7
In Stock
3 Improve soil aeration and drainage by mixing in horticultural perlite to prevent the soil from staying overly saturated.
Legigo Perlite 15qt
Legigo Perlite 15qt
14.2 L • Perlite
$22
In Stock
warning

Blackberry Leaf Spittlebug (or similar Hemiptera)

While less common as 'flying' pests, certain small black insects may be attracted to the lush foliage of large-leaved hostas to feed on sap.

Common
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How to confirm: Inspect the undersides of the large blue-green leaves for any small, dark, stationary insects.
build How to fix it
shopping_cart Recommended Products
1 Apply an organic insecticide spray to eliminate the adult insects and protect the foliage from sap-sucking damage.
Bonide Captain Jack's Neem Oil 32 oz
Bonide Captain Jack's Neem Oil 32 oz
0.9 L • 1 pcs • Organic
$10
In Stock
2 Check the soil surface for fungus gnat larvae, which often resemble tiny black flies, and use yellow sticky traps to capture adults.
Super Ninja Fungus Gnat Traps - 30 Pack
Super Ninja Fungus Gnat Traps - 30 Pack
30 pcs
$7
In Stock
3 Inspect the underside of the large leaves for any remaining nymphs or eggs to prevent a secondary infestation.

Other Hosta sieboldiana Frances Williams problems

Your plant might also be experiencing one of these issues:

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eco Brown Leaf Tips chevron_right
eco Drooping Leaves chevron_right
eco Fine Webbing chevron_right
eco White Powder chevron_right
local_hospital All symptoms eco All plants with tiny black flies
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