Begonia Monza Scarlet Tiny Black Flies - Causes & Fixes

Jump to cause: Fungus Gnats Overwatering and Root Rot High Organic Matter in Soil

search Possible Causes

error

Fungus Gnats

The tiny black flies are likely fungus gnat adults, which thrive in the consistently moist soil required by Begonia Monza Scarlet. Their larvae live in the top layer of substrate, feeding on organic matter and decaying roots.

Very Common

lightbulb

How to confirm: Set a yellow sticky trap near the plant to confirm the presence of flying adults.

build How to fix it

shopping_cart Recommended Products

1 Deploy yellow sticky traps to capture the adult flying gnats and break the reproductive cycle.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

2 Allow the top inch of soil to dry out completely between waterings to disrupt the larvae's moist habitat.

GROWIT Soil Moisture Meter - Blue

Water Meters

$12

In Stock

3 Apply a top dressing of horticultural perlite to improve aeration and create a drier barrier for larvae.

error

Overwatering and Root Rot

Excessive moisture in the Begonia's potting medium creates the perfect breeding ground for fungus gnat larvae and promotes fungal growth. This environment can lead to stem softening and dark, mushy root tissue.

Very Common

lightbulb

How to confirm: Gently lift the plant from its pot to check if the soil is waterlogged or if roots feel slimy.

build How to fix it

shopping_cart Recommended Products

1 Immediately reduce watering frequency and allow the top inch of soil to dry out completely to disrupt the fungus gnat life cycle.

GROWIT Soil Moisture Meter SMM-V3

Water Meters

—

2 Repot the plant in a well-draining, fresh medium and inspect roots for mushy, dark tissue; trim away any rot and replace with a highly aerated mix containing perlite.

3 Apply yellow sticky traps near the soil surface to capture adult flies and prevent further breeding.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

warning

High Organic Matter in Soil

Begonia Monza Scarlet requires nutrient-rich soil, but a high concentration of decomposing peat or compost provides an abundant food source for insect larvae. This attracts flies that lay eggs in the nutrient-dense upper substrate.

Common

lightbulb

How to confirm: Examine the top inch of soil for small, white, worm-like larvae moving through the medium.

build How to fix it

shopping_cart Recommended Products

1 Apply a biological insecticide to eliminate the adult flies and larvae by targeting the life cycle of the fungus gnats.

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 prevent them from laying more eggs in the soil.

Super Ninja Fungus Gnat Traps - 30 Pack

30 pcs

$7

In Stock

3 Reduce moisture in the top layer of the soil and consider adding a layer of perlite to improve aeration and decrease organic food sources for larvae.