What to observe

• Small dark adults running or flying near the media surface
• Larvae in moist media under close inspection
• Persistent wet media or algae/fungal growth that supports larval habitat
• Weak young plants where root injury is plausible

Common look-alikes

• Shore flies
• Other small flying insects
• Seedling problems caused by overwatering without meaningful gnat pressure
• Root disease unrelated to insect feeding

Evidence that improves confirmation

• Use sticky cards for adult trend data
• Inspect the media or use an appropriate larval sampling method
• Separate insect presence from proof that insects caused the plant symptom

Risk context

• Chronically wet media favors habitat development
• Propagation areas can be particularly vulnerable
• Algae and decaying organic matter can support populations

Management principles

• Correct avoidable overwatering and improve media/aeration practices where appropriate
• Remove standing water and unnecessary organic debris
• Monitor adults and larvae separately
• Use only lawful, crop-appropriate biological or other controls and verify population change

Keep the conclusion proportional to the evidence

Use a confirmed identification when available. When evidence is incomplete, label the conclusion as a suspicion or differential rather than presenting it as proven.

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