PCT sat down with University of Tennessee Entomologist Dr. Karen Vail to get an update on ant control.
Editor’s note: PCT recently interviewed University of Tennessee Entomologist Dr. Karen Vail, co-author of the ant chapter in the 10th edition of the Mallis Handbook of Pest Control (below), about current trends in ant control.
Additionally, Vail noted there were several changes to the most recent edition of the Mallis Handbook of Pest Control in regards to ants. Since there are many new invasive ant species affecting PMPs in the United States, scientific and common names were updated when research on morphological or molecular techniques revealed a different lineage then previously understood.
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Q: Has there been any recent research that impacts how PMPs control ants?
A: Recent research at North Carolina State University indicates that the invasive Asian needle ant is outcompeting the invasive Argentine ant, so PMPs from the mid-Atlantic to the Southeast may be interested to know that the Asian needle ant can be managed with granular baits. Researchers from Vanderbilt University have identified the odor receptors of the Florida carpenter ant and are in the process of determining the behaviors that certain odors cause. Although not directly applicable to pest management at this moment, it certainly hints at the possibilities of future ant control strategies (see the April 2013 issue of PCT). Results of Laurel Hansen’s 2011 ant survey of PMPs conducted with NPMA show that most ant jobs are performed for carpenter ants, odorous house ants and pavement ants. Where is all the research on pavement ants?
Q: How important is it for PMPs to understand the biology and habits of each species?
A: I was fortunate to hear Austin Frishman speak a few months ago and something he said really stuck with me. When combating a pest, ask yourself the following questions: “What is it?” “Why is it here?” “How can I solve the problem for my client NOW?” and “What are the long-term solutions?” You can’t answer these questions without understanding the identification, biology and habits of the ant in question.
Q: Why is it important to identify invasive ants? What’s the best way for PMPs to go about getting a “new” ant identified?
A: Let’s define an invasive species. An invasive ant is one that when found outside of its native ecosystem causes some sort of harm (economic, environmental or human health).
Typically, invasive ants are displacing native species and are very abundant in their new environment. Most of you are familiar with imported fire ants and Argentine ants that were introduced into the United States in the past century or earlier, but an increase in recent global trade brings more chances for the introduction of new pest ants.
Most of us fail to identify a new invasive ant until an infestation is unsuccessfully “managed” and the client is upset. Finally, after much aggravation, we take a second look and the options in the pictorial key just don’t look like your ant. You can try to use web sites with wonderful 3D color images of ants such as http://antweb.org, Joe MacGown’s Ants of the southeastern U.S., and Alex Wild’s Photography, or work the keys in the PCT Field Guide for the Management of Structure-Infesting Ants or the Mallis Handbook. But in the end, you’ll need to find an expert to confirm your identification.
An expert could be the urban entomologist or myrmecologist (ant specialist) at a nearby university, your technical director or even your extension agent. Many county extension agents have the ability to upload high-quality digital images from a microscope and send them to the appropriate web site or specialist. Sometimes even the experts can’t agree on an identification and it might take a few years to sort it out (see the tawny crazy ant in the next question); however, molecular analyses are providing better insight into the identification of ants.
It’s important to get the ID right so others can be informed of the ant’s presence and the damage it causes. Once informed, the PMP can locate these ants when populations are small and thus increase the chances of control. Proper identification will lead to better management because we can determine nesting sites and food preferences and thus select the appropriate bait, other insecticide or approaches necessary to successfully control the pest.
Q: Are there any new invasive ants that are of specific concern for PCT’s readers?
A: Many of our invasive ants share the same characteristics, they lack territories, often have interconnected nests with many queens and may be associated with people or disturbed habitats. Here’s a few that we have been “recently” introduced into the U.S. or have been with us for many decades and recently increased their status to invasive. For images of these species, please see the Mallis Handbook of Pest Control Color Identification Guide in the middle of the book. Here are some examples:
The tawny crazy ant, Nylanderia fulva. There was much discussion on the identity of the ant called the Rasberry crazy ant that was first noted in Texas in 2002. As it turns out, last September it was determined that Rasberry crazy ant was the same ant as that referred to as the Caribbean crazy ant in Florida, and probably other locations along the U.S. Gulf Coast. The identity of the ant was determined to be Nylanderia fulva, an invasive ant from South America, and the common name of tawny crazy ant was accepted by the Entomological Society of America on April 22, 2013.
The Asian needle ant, Pachycondyla chinensis. First discovered in the U.S. in the 1930s, its distribution (Georgia, North Carolina, Virginia and Washington, D.C.) remained fairly stable for decades. A formidable stinging ant, it has displaced native and exotic species, including the Argentine ant. It feeds on insects, especially termites, and uses tandem carrying to bring a sister to a food source rather than laying a pheromone trail for group recruiting. In the last decade it has been found in Tennessee, Alabama, South Carolina, New York, New Jersey, Connecticut, and even Washington and Wisconsin. Latest research indicates that granular baits may provide reasonable suppression.
The European fire ant, Myrmica rubra. Records indicate this ant was established in the early 1900s in Massachusetts, and although periodically stinging complaints were recorded, it was not until the 1990s that complaints started to escalate, especially in Maine. Now established in New England, Ellie Groeden’s lab at the University of Maine is involved with the latest research on this pest.
The dark rover ant, Brachymyrmex patagonicus. Described by Jeff Tucker as the “single-most difficult ant to control in the Southeast,” this minute, pudgy ant is now established throughout most of the southeastern coastal states and has been found in Nevada and Arizona.