Thrips vs Fungus Gnats: How to Tell the Difference

Tiny insects around your houseplants can be confusing. Flies hovering above damp compost often suggest fungus gnats, while slender insects on leaves, together with silvery feeding damage, may indicate thrips. Check both the plant and its compost before choosing a treatment.

This guide explains the differences between thrips and fungus gnats, what to look for and how to approach each problem.

Explore LAVA-LITE NO-GNATS natural fungus gnat control.

What do thrips look like?

Thrips are small, slender insects that feed on plant tissue. Look closely at leaves, stems, flowers, buds and new growth.

• Long, thin insects that can be difficult to spot.
• Silvery streaks or patchy scarring on leaves.
• Tiny dark specks alongside feeding damage.
• Insects hiding in buds or tightly folded new growth.

Leaf damage is a useful clue, but it is not a diagnosis on its own. Inspect the insects as well. Some thrips species also have life stages in the growing medium, so the distinction is not simply “leaves versus soil”.

What do fungus gnats look like?

Adult fungus gnats are small, dark, mosquito-like flies often seen around houseplant pots. Their larvae develop in moist growing medium.

• Small flies with slender bodies and long legs.
• Adults walking over compost or flying near the pot.
• Flies becoming noticeable when the pot is disturbed or watered.
• A recurring problem where compost stays consistently damp.

Flies around the compost suggest fungus gnats, but check their appearance rather than assuming every small flying insect is the same pest.

Why are thrips and fungus gnats confused?

Both can be noticed as tiny insects around houseplants, but their feeding habits and the damage they cause differ. Treating leaves alone will not address fungus gnat breeding in damp compost. Equally, a fungus gnat top-dressing is not a substitute for treating a confirmed thrips infestation.

How to manage fungus gnats in houseplants

Start by checking watering habits and drainage. Allow the compost surface to dry between waterings where appropriate for the plant, empty standing water from saucers and remove decaying plant material.

Using NO-GNATS as a top-dressing

LAVA-LITE NO-GNATS is a natural mineral top-dressing for fungus gnat control. Apply it according to the product instructions, alongside watering and drainage practices suited to your plant.

A top-dressing targets the surface of the growing medium. Continue monitoring the pot rather than expecting every adult fly to disappear immediately.

Shop NO-GNATS and read the application instructions.

What to do if you find thrips

Separate the affected plant from other houseplants where practical, inspect nearby plants and confirm the pest before selecting a treatment. Check leaf undersides, buds and new growth regularly.

Appropriate biological controls or treatments may help, depending on the plant and conditions. Follow the supplier’s instructions and any product label carefully. NO-GNATS is intended for fungus gnat control, not as a treatment for thrips on leaves.

Thrips vs fungus gnats: quick checklist

• Small, mosquito-like flies near damp compost: fungus gnats are a possibility.
• Flies appearing when you water or disturb a pot: inspect for fungus gnats.
• Slender insects on leaves with silvery scarring: inspect for thrips.
• Dark specks alongside leaf damage: check closely for thrips and other leaf pests.

It is possible to have more than one pest at the same time. Check the leaves and compost separately, then choose an approach for the pest you identify.

Choose the right approach for your houseplants

Correct identification is the best starting point. For fungus gnats, focus on the growing medium, watering and drainage. For thrips, focus on confirming and managing the insects feeding on your plant.

If you have identified fungus gnats, discover NO-GNATS mineral top-dressing and follow the application guidance for your pots.