YELLOW or CITRONELLA ANTS (aka fall flying ants)

Barbara J. Bromley, Mercer Co. Horticulturist 2004

During late summer and fall and also in late winter/early spring, the invasion of flying reddish yellow or reddish brown ants is common. Homeowners fear that these 3.0 mm to 5.0 mm long winged insects are termites. However, they are usually reproductives of either the smaller or larger yellow ant. (Acanthomyops claviger andAcanthomyops interjectus, respectively) The larger yellow ant is also known as the citronella ant because when crushed or alarmed, it gives off a pronounced citronella or lemon verbena-like odor.

Although one species of subterranean termite found in NJ will swarm in the fall, most termite swarms are found in spring from early March to late May. This necessitates knowing the difference between flying ants and the flying termite reproductives.

• Antennae: Termites have beaded antennae similar to a bead chain used for holding keys, while ants have elbowed antennae with the bend at or near the middle.
• Wings: Termites have four wings, equal in length and about twice the length of their bodies. Ants also have four wings, but the hind wings are shorter than the front wings and are not twice the body length. Also, ant wings have prominent wing venation. Termite wings resemble milk glass with no prominent veins.
• Body shape: Ants have a narrow-waisted (like an hourglass) three-segmented body. Flying termites appear to have two body segments without the constricted waist.
• In most instances winged termites shed their wings shortly after swarming.

Yellow ants usually nest outdoors next to foundations or under slabs. They feed almost exclusively on honeydew, a sweet material obtained from root feeding aphids or mealybugs. Therefore, workers seldom invade buildings looking for food as do many other ant species. However they may be a problem by pushing soil through cracks in foundations and slabs. The winged yellow ants may cause concern when they fly into basements or living quarters causing a “termite swarm” scare. Also, the very large number of yellow ant reproductives (with wings) and the smaller workers (without wings) that may congregate on the side of a building on a mild fall to early spring day may be alarming.

Ants seek the path of least resistance as they travel from the soil through openings in foundations or slabs. To reduce an invasion, measures should be taken to seal or caulk entry points such as cracks in slabs, gaps around water faucets or dryer vents, and openings around door sills and cellar window frames. In most cases, once cracks are sealed, yellow ants cease to be a problem. Stray ants can be crushed or vacuumed up. If mechanical control measures fail to reduce the problem, then pesticides registered for ant control can be used to treat the soil adjacent to the foundation. Follow label instructions.
IPM CONTROL STRATEGIES: Larger yellow ants