Those Darn Ants!

Foraging Argentine ants (Photo: Alex Wild).

How many times have you been called to the teachers’ lounge, a classroom, or bathroom because someone has seen ants in and around a sink or other water source? Let's run through what might be a typical scenario:

Your look around and rule out the presence of a leak or other plumbing issue. You determine that the ants are just after whatever water is in the sink. You spend some timing looking around, but because the ants haven’t established a foraging trail, you can’t figure out how they are getting in.

So you do what you can in this situation – perhaps you make a crack-and-crevice application into any obvious cracks or gaps in an effort to keep the ants out. Maybe you even seal up a couple of gaps with some caulk or other sealant. You go through your regular spiel about making sure that food is stored properly, garbage is taken out regularly, excess water is wiped up, etc. And you’re done.

Until you get another call about ants in the same area – just a couple of days later! So, you go back, look around again – this time taking even a little more time to check for potential entry points.You know that for optimal results, you really need to find and treat the source (i.e., the nest). So you go outside and look for a nearby ant nest but find nothing. You watch the ants closely, but never see where they are coming from or going to. So you make another, more thorough crack-and-crevice application into the gaps in the area. You treat a few extra openings that you somehow missed before. And you’re done.

You wish! You get yet another call about ants in the same area. So, what can you do now? What is going on?

Well, I can tell you that I’ve had this exact same problem occur at my house – in my kitchen around the sink. And I tried everything that I wrote about above. I checked outside for a nearby nest but found nothing. Since I could find no nest, I realized that my best bet would be to attempt to keep the ants out of my house. So I treated all the obvious gaps with a crack-and-crevice insecticidal spray. I sealed up whatever openings I could see. Yet, I kept getting ants around my kitchen sink. I watched the ants carefully to try and determine exactly where they were getting in. But I could find nothing, because while there were several ants around the sink, there was never a real distinct foraging trail.

Ants recruited and feeding on jelly 
(Photo: Patty Alder).

Then it hit me: I realized that in order to find the entry point(s), I needed a distinct foraging trail. So I placed a very small dab of apple jelly on a piece of cardboard, placed it on the counter near the ants…. and waited. It didn’t take long – maybe 20 minutes or so – for more ants to show up (see photo at right).

Pretty soon, I had myself a pretty distinct trail of ants going from my kitchen sink to…. a small opening where the caulk had come out in an area on the counter right behind my sink. (see photos below). A small opening that I had overlooked! So I treated that opening with a crack-and-crevice spray and guess what? No more ants!

Foraging trail can be followed from the jelly down 
the window frame (Photo: Patty Alder).

Ants were coming in through a gap in the counter 
behind the sink (Photo: Patty Alder).

If you have this issue with ants, set out a bit of jelly on an index card in a couple of areas where you are seeing the ant activity. If the ants are in a classroom, make sure you explain to the teacher that he/she needs to keep the children away from the area so as not to interfere with the ants’ activity. Check back in about 30 minutes for a trail of foraging ants and carefully follow the ants to see if you can determine how they are gaining entry into the area. If jelly does not seem to attract the ants, you could try a small piece of cheese or a potato chip (I wouldn’t use peanut butter in schools because of all the issues with allergies). Once you figure out where the ants are coming in, you can treat that opening with a crack-and-crevice application. You may even want to seal up the opening after it has been treated.

Good luck and happy ant hunting!