Baiting Carpenter Ants

Q: We have tried a number of different baits to control carpenter ants. We have scattered baits around the perimeter of houses and when we find carpenter ant trails or activity around a tree or other nest site we scatter the bait in these locations also. None of this has been very successful. Do you have any recommendations for improving carpenter ant baiting? (L.V.)

A: I think you will find that carpenter ants are among the most finicky of all ants when it comes to artificial bait acceptance. There are a couple of things you should keep in mind when using bait for carpenter ant control concerning how and where baits are used or placed. First, it has been my observation that carpenter ants, despite their size, are candidates for the wimps of the ant world. I have noticed when carpenter ants are challenged by other ant species around a food or resource that the carpenter ants will often leave and let the other ant exploit the resource. If there are other ant species commonly foraging in the area where you are baiting for carpenter ants, you may find that the other ants are the ones that remove the bait while the carpenter ants avoid the confrontation. This is very true when fire ants are found in the area. You may need to place your baits late in the day or even during the evening hours so that the mostly nocturnal carpenter ants have a chance to feed on them before other ant species find them. Obviously you would not place baits designed to control carpenter ants next to or directly in the middle of another ant species’ foraging or nesting area.

I have also found that carpenter ants seem to prefer exploiting a pile of small accumulation of bait much more readily than they feed on widely scattered bait particles. As a result, you may find better acceptance with carpenter ants when you place small accumulations directly on or next to a known carpenter ant trail. This will make it easier for the carpenter ants to mark the food source and recruit other members of the colony to that location. Finally, try using the new Advance Granular Carpenter Ant Bait from Whitmire Micro-Gen. I have had excellent results with this material on several species of carpenter ants when following the previous recommendations.

OVERHEAD BAIT APPLICATION

Q: In many of the homes we treat for carpenter ants there are voids above ceilings that can only be accessed through small holes drilled in the ceiling. Getting granular baits into these voids has been difficult. Can you recommend a piece of equipment or method for dispersing upward into ceiling voids through small openings? (B.M.)

A: B&G Equipment Company has a relatively new piece of equipment called the Long Reach Granular Dust-R. This piece of equipment was made for exactly the type of application you are describing. Additionally, I believe that their Mini Dust-R and their Hand Dust-R will also apply granular bait materials. You can contact B&G at 800/544-8811 for the location of their nearest distributor.

YELLOWJACKET COLORATION

Q: A large part of our work involves the control of wasps, bees, yellowjackets and hornets. On several occasions I have opened the yellowjacket or hornet nest after killing it and found individuals within the nest that did not look like the wasps I had seen on the exterior. In other words, there appeared to be two different wasps in the nests. Their size was different and their color was different. I have not seen this often but I have never been able to explain to my customers why we see this when we tear the nests out. Is there a good explanation for this? (J.R.)

A: I can think of only two possible explanations for what you have seen. First, if this is occurring late in the season then you may be seeing reproductive forms (males and females) which will be larger and perhaps have some color variations or variation in markings on their body which would make them appear to be a different species from the workers in the nest.

However, a more likely explanation is that you have found a situation where one species has taken over the colony of another. The term used to describe this phenomenon is called “usurpation.” This phenomenon has also been called social parasitism. Generally, a queen of one species takes over an existing nest of another species. She does this by killing the founding queen. The original worker wasps continue to maintain the nest and feed the larvae even though all of the new eggs being laid are the product of the new queen which is of another species altogether. Usurpation of an existing colony can also occur within members of the same species. But this would not account for your observation of differences in coloration, size and markings. This type of parasitism is not uncommon, but I’m uncertain as to the frequency with which it occurs.

Jeffrey Tucker is president of Entomology Associates, Houston. Questions can be sent to Q&A, c/o Entomology Associates, P.O. Box 70375, Houston TX 77270, or faxed to 713/681-9069.