[Annual Ant Control Issue] One Crazy Ant

New pests often generate the most attention (let’s say that "new pests" are ones that have been recently described as pestiferous or have recently been brought to our shores). It’s not that more established pests are now less prevalent or less dangerous to our business, it’s just that new pests are "new." New pests also get pest management professionals excited about the prospect of adding glossy photos of insects or other creatures to their arsenal of sales brochures and including them in their contracts. Sometimes though, new pests like Paratrechina pubens — or the Caribbean crazy ant (a proposed name) — just don’t fit that mold.

A LITTLE HISTORY. Paratrechina pubens was originally described in 1893 from St. Vincent, Lesser Antilles, and was originally collected and identified in the United States in 1953. More recently (1990, 1995 and 2000), P. pubens was described as a pest ant found in the extreme southeast U.S. Within the last three years P. pubens has been documented in several other areas with a focal point around West Palm Beach, Fla. It is known to the author that P. pubens has been present at several locations in the West Palm Beach area for more than three years despite management practices aimed directly at mitigating its spread.

While the name "Caribbean crazy ant" sounds exotic and fresh, this ant is similar in structure, if not numbers and habits, to many other species of pest ants. Many pest management professionals have dealt with crazy ants; even more have heard of them. A complex of species inside the Paratrechina genus, crazy ants can be found just about anywhere. Some species of Paratrechina (e. g. P. longicornis) have been described ranging from Florida to South Carolina, west to Texas and with a presence in California and Arizona. Crazy ants may sporadically be found in almost any state of the United States due to ease of long distance shipping and controlled climate areas (such as malls, hospitals, indoor recreation areas, etc.).

Through recent personal observation, the Caribbean crazy ant differs from other common Paratrechina spp. in that they seem to be much more mobile (reproductives may move with workers) and more persistent than other crazy ants (monocultures of this ant are not uncommon). Some of the habits of the Caribbean crazy ant parallel other pest ants, such as Argentine ants and red imported fire ants. The Caribbean crazy ants appear to nest in the soil subsurface under leaf litter or debris. The Caribbean crazy ant has trail patterns three or four ants wide, as is also commonly seen with white-footed ants. Lastly, like other Paratrechina, the length of P. pubens ranges from 2.5-3 mm with distinctively long legs and antennae. However, P. pubens is a golden brown color that is usually lighter than the Argentine ant.

A SOLUTION? So what does this all mean? We have an ant that could be confused by appearance with an Argentine ant, an ant that can be found in monocultures like the red imported fire ant and could be as adaptable as others in its genera. Oh, by the way, in heavy infestations it appears as if the ground beneath your feet is quietly pulsing with ant activity. In fact, on one particular site, I would venture to say there were millions of ants foraging along the ground.

The solution here is to modify the habitat so it is unacceptable for the Caribbean crazy ant. The easiest way to do this is by removing leaf litter, maintaining perimeters around buildings with pea rock-size particles, reducing the over usage of mulch in plant beds and generally removing good harborage sites (no more railroad ties, please). Besides the obligatory tactics previously mentioned, the use of insect growth regulators and the consistent treatment of harborages are keys to reducing the populations of the Caribbean crazy ant.

As far as I know, the Caribbean crazy ant doesn’t particularly like to forage inside structures and seems to be susceptible to directed treatments. However, the efficacy of both liquid and granular baits remains to be seen. I have a feeling that the initial use of baits will not present enough active ingredient to the entire population in an established area to limit their growth, although baits used as a preventive tool may prove useful.

Paratrechina pubens infestations seem to be isolated to several local areas, but this may be due to misidentification or lack of observance. Paratrechina pubens could be poised to become a major pest if its range extends to other areas where other Paratrechina spp. are known and it maintains its recent habits.

The author is technical services manager for Western Pest Services, Deerfield Beach, Fla. He can be reached at mremmen@pctonline.com.

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PARATRECHINA
PUBENS 411

Keys to ID

Long legs and 12-segmented antennae and large scape with no club

Monomorphic ant with uniform golden-brown to reddish-brown color

2.5-3 mm in length with lots of small hairs over the body

Pros

Doesn’t seem to forage inside structures as much as other ants

Appears to be susceptible to common ant labeled products

Seems to be confined to Florida in the upper 48 states

Cons

Possibly millions of workers in heavy infestations

Looks to have multiple nests and queens

Very mobile reproductives have been noticed to move with workers

Could easily be spread or transported to other areas