Citronella Ant (Lasius interjectus / Lasius claviger)

Smells Like Lemon • Swarms Around Foundations

Citronella Ant – Connecticut Identification & Seasonal Swarm Guide

Citronella ants, also called large yellow ants, are known for the lemony scent they release when crushed. They rarely enter homes but cause concern when they swarm near foundations in late summer and fall.

Identification:

• Size: ⅛–¼ inch
• Color: Bright yellow to yellow-brown
• Smell: Strong lemon/citronella odor
• Behavior: Slow-moving

Swarms often appear in basements or along foundation walls.

Behavior & Habitat:

Citronella ants nest:

• Beneath slabs
• Under rocks
• In soil near foundations
• Under logs and firewood

Their swarms typically occur August–October, often alarming homeowners.

Why They Appear in Connecticut:

These ants thrive in:

• Moist soil
• Shaded yards
• Beneath basement slabs

Heavy August humidity increases swarm activity.

Signs of Citronella Ants:

• Sudden winged ants indoors
• Swarming near foundation cracks
• Lemon-like odor when crushed
• Soil disturbance near slabs

When to Call a Professional:

If swarms occur indoors or around structural gaps, treatment can help prevent reentry.

Ant Control CT 

Additional Links:

• Odorous House Ant 
• Pest Prevention