Caribbean, brown, hairy, Rasberry crazy ant

By: Faith Oi

Whether you call this ant the Caribbean, brown, hairy, Rasberry crazy ant or Paratrechina pubens or P. near pubens, it is a pest control challenge as yet another seemingly invasive ant hits our market. This ant seems to be distributed from Florida across the I-10 corridor to Texas. It has been recorded to be in Florida since 1953. We began to receive reports of this ant being a problem around 2001-2002. Texas reports this ant becoming a problem in 2002 and Mississippi in 2009.

It does not sting, but some people do complain of being “nipped.” While ants have chewing mouthparts, the “nipping” sensation could also be exacerbated by the creepy-crawly feeling of hundreds of ants covering you if you stand still too long in a heavily infested area.

There is great confusion over the exact name and classification of this ant, and I apologize in advance to my ant taxonomist friends for this simplified description. You know you have a problem with this crazy ant if you have thousands and probably millions of ants that are brown, have a striped appearance when their gaster is full, are about 3 mm long, and are monomorphic with a one-petiole gaster. These ants move with what looks like erratic, non-directed running (like our other crazy ants).

If you have one of these accounts as a pest management professional (PMP), you can suspect that you have this ant in your area if your best technician goes to do an ant job and you get a callback. The callback is not because the perimeter spray failed, but because so many dead ants have piled up on the treatment area that it has covered your treatment up, leaving invading ants free access to the structure. If your best technician baited for these ants, you get a callback in less than a week — because the population may have been suppressed, but invading ants have simply moved into the void.

Now, the scientist side of me does care about the differences in the length of a cluster of setae on the male ants that may be part of the separation between P. pubens (Caribbean crazy ant, also known as the brown or hairy crazy ant in Florida) and P. near pubens (Rasberry crazy ant in Texas). However, I have not found a way to take the information generated on the setal arrangements on male ants and translate it into control recommendations.

What we do know about control is that a single-tactic approach will most certainly lead to failure. Any perimeter spray alone will eventually break down or be covered up by dead ants. A non-repellent perimeter treatment will kill ants, but they die inside structures, leaving occupants unhappy. Repellent perimeter treatments are helpful from preventing invading ants from entering into a structure, but they do not have the transfer effect baits would have. Baits alone are probably not sufficient at the current label rates.

Clearly, management of this ant requires a combination of treatments: a perimeter spray around structures with baits applied further away. Make sure that the ants are feeding on the bait you plan to apply. Eliminate food sources and harborage as much as possible.