After I woke up yesterday morning, I went out to my front porch to see what the day was like and see if there are any visitors waiting for me there. (Sometimes there are amazing visitors like a 12 inch long walking stick or a huge praying mantis, or maybe a toucan in a nearby tree. You never know what miracle of nature you might see!

Well, I didn't see any noteworthy visitors but I decided to sweep the porch before breakfast.

As I was sweeping I noticed an unusual amount of beetles running up on the porch - maybe 10 in 5 minutes. I have a "no insect" policy on my porch and in my house unless it's a walking stick or some other "good" insect which there are very few of in my estimation.

Basically, if you are an insect, and you come into my house uninvited, you are risking your life!

But I wondered why so many beetles were coming up to the porch... I was just finishing up sweeping after having killed these 10 or so beetles and was about to go back inside and eat my breakfast and have my coffee. I turned around  the door and suddenly - like they must have appeared in 3 seconds or so - there was a swarm of army ants on the porch - maybe 500-1,000 all in a group creating a big black spot.

"Oh, NOW I know why all those beetles were running up on the porch - they were running from the clutches of the army ants!"

Costa Rica Army AntsHere's a picture I found on the net but this is  just a few of them surrounding a scorpion, not an entire division heading into the house!

Now, here's the background on this battle:
As mentioned I have a "no insect" policy re my house, and I particularly don't like ants.

Why? Because where I lived in the U.S. if ants came into your house soon more would come and soon I was struggling for a month or two to get rid of them. I'd have to go out and buy various types of poison and try each one because some work for some ants and not for others, and some ants just seem to be immune to any poison (much like the leaf cutter ants here in Costa Rica).

So, no: having thousands of ants enter my house doesn't seem like a good idea to me. Not at all!

However, my Tico friend, confidante and gardener/jack of all trades here in Costa Rica has told me that these Army Ants will not stay in the house. He says they will enter, they will go through the house and clean it of all insects, dead or alive, and then they'll leave wihin a couple hours and the house will be cleaner.

Of course I believe him; he has lived here his entire life.

And yet I think "But what if they DON'T leave?" What if these are a slightly different type that he doesn't know about? What if they USUALLY leave but this time they don't? What then?

Can you imagine the hassle of trying to get thousands of ants to leave your house? And would I be able to sleep tonight if they don't leave? If they don't leave I would have NO alternative but to use poison inside the house to get them out, and I don't want to have to do that!

So, I decide to FIGHT THEM OFF.

This is the 2nd time they've come. The first time was about 9 months or so ago and my wife and I didn't know anything about them and my Tico friend was not available to ask so we fought them off. Took us both over an hour to fight them that time. You can read about our first encounter with them here.

The short version of that first time is this: they would attack from 2 sides so one of us was on one side and one on the other. We tried avoiding using poison and at first that seemed to work - using a broom and using an organic combination of tea tree oil, peppermint oil and vinegar spray. But after awhile we had to resort to chemical insecticides.

It took us about an hour of hard work to fight the last group off but we won.

When our Tico friend found out he said we shouldn't have killed them and told us how it's great when they come and clean his house of bugs. i said, "Well may be, but I really don't like ants in my house. But maybe next time I'll let them in."

"Do you think they'll come back and try again soon?"
"No," he says. "They probably put your house on their black list!"
"Good!" I said and we both laughed.

So yesterday when I suddenly saw them on my porch, just feet away from my door, my instinct kicked in, in spite of my being told that I should let them in. It was just a natural reaction and I don't think I even considered for a moment the idea of letting them in my house.

Costa Rica army antsThis is a photo of some that were in our driveway some months ago. These are just a few stragglers after the main group had crossed. So this doesn't give you the idea of what it's like to see a huge black spot of thousands of ants together going to invade your house!

I sprang into emergency mode!

I shut the door, grabbed a broom and began sweeping them back off the porch. At first this seemed to work. But soon it wasn't enough as more and more came onto the porch, now they were coming on the other end.

I grabbed the tea tree oil/peppermint oil/vinegar spray that we try to use instead of chemicals for all insect problems, and it seemed to be working... for a few minutes.

I did get them off the front porch, but now they were attacking the side wall of my house, and was afraid they'd find a way in through the sliding window.

I began with the spray but it wasn't working. I went to the broom and kept sweeping them off the wall with the broom. There was a break in  the action but then I saw that there were hundreds more - maybe thousands - in the yard.

"Water!" I thought. I ran around to the other side of the house, grabbed the hose, took off the sprinkler and attached the spray nozzle and ran quickly back to the other side of the house, where now there were dozens of ants climbing up the wall.

I turned the hose on full jet and sprayed them all off the wall and then turned the jet spray onto all the ones on the ground. They are not easily discouraged. Many kept coming in spite of the strong spray and so I had to go back and forth between the wall and the yard. I figured once the ground was saturated with water surely they'd give up.

But they didn't. Now they were attacking the back of the house AND the side!

Now I was running back and forth with the hose between the back and the side of  the house!

As soon as there was able to slow their advance down a bit I then ran in the house to grab more vinegar, and peppermint and tea tree oils and made some more organic insecticide. I also remembered that dish soap used to help get rid of them back in the U.S., so I grabbed a bottle of that too and put some in a squirt bottle with water.

I ran back out and now there were more than ever on the walls. I first used the hose to get them off the walls then I sprayed both the dish soap and the organic insecticide all around the bottom part of the house.

Like the other things, it seemed to slow them down. But did not stop them!

After a while of trying this method of using water, soap and organic insecticide, I saw that it wasn't stopping them.

"Sorry, fuckers!" I said out loud to myself, "But now you're pissing me off! I'm getting the chemical insecticide out!"

I hate using chemical insecticide and I try very hard not to use it. But sometimes it's the only way, it seems.

So I sprayed the insecticide around the bottom of the house. Again, it slowed them down and I thought maybe it worked. It slowed them down a great deal.

But after a few minutes they just forged ahead through the poisoned area and started climbing up  the walls again, both on the side and the back of the house!

Now it was personal! I sprayed more poison! I was ranting at them. "You are not going to get in my house, motherfuckers!"

Maybe the poison was getting to my brain and making me nuts. Maybe it was just because I'd been fighting hard, non-stop for 2 hours or so!

Or maybe it's just because I hadn't been able to have my breakfast and coffee yet. But whatever. After fighting with great effort to keep them out of the house for 2 hours, I was not going to let them in now!

So I kept using the hose to spray them both on the ground and on the house but as much as I could divide my attention, I began concentrating more on the troops in the yard, drowning them, and spraying some poison on them. Some were still coming towards the house, but more were turning away.

Maybe I was winning this battle after all. I certainly hoped so,  because honestly I was really tired of the fight and the chemicals were bothering me, I could taste them in my mouth and my head was hurting.

I was beginning to think, "If they don't give up soon, I may have to surrender the house to them. I can't go on like this all day!"

Well, after THREE HOURS of non-stop emergency-mode fighting them, I won. There were still a few stragglers here and there but I was able to more slowly deal with them and soon there were none. They left to seek out a less hostile neighbor.

But the whole rest of the day I couldn't relax. I kept thinking they might come back. If they did, I decided, I'd have to let them in. I was spent. I had no fight left in me. Maybe it was the chemicals or maybe it was just the intensity, but I was exhausted from fighting them for 3 solid hours.

They didn't come back.

A gringo neighbor visited me later in the day and I told him about my battle and he said, "Yeah, they came around our house but didn't go inside but I was told not to kill them."

I said, "But here's the question: Would you let them inside?"

He said, "Yeah, I guess I would. They say they always leave after an hour or two. Next time don't drive yourself nuts fighting them, just trust in the system and let them come in. Apparently that's what all the Ticos do."

"Yeah, maybe you're right," I said. "I don't think I want to fight them again. I wouldn't have started if I'd known it was going to take 3 hours of intense fighting! Last time it only took us about an hour to get rid of them."

So there you go...

My second battle with the Army Ants was a tough one!

Next time I'm really going to try to relax and just let them do their thing and hope they really do leave after an hour or two like everyone says.

Some things are just so different here, it's hard to accept. Like I said, my experience with ants my entire lifetime has been that you should never let even one ant into your home because if you do, soon you'll have an infestation that could literally take months to get rid of. Pretty much like cockroaches...

If someone told you to let a swarm of cockroaches into your house, would you do it? Or would you feel like I did about the ants?

army ants

These are not Costa Rican army ants but it gives you an idea of what they look like when there's a large group of them together. The group on my porch was perhaps 5 times larger than this group.

So even though I knew it was probably best to let the Army Ants in as I was told by my Tico advisor and friend, I just couldn't accept it!

So what will YOU do when you are faced with the Army Ants?

Leave your comments below about what you will do if the Costa Rica Army Ants  want to enter your house!


  1. Graham Campbell on February 27, 2017 at 3:30 pm

    I cope with ants – they don’t eat much!

    But roaches – death to every damn one in the world. Yeah, they are the garbage scavengers of last resort I know – BUT.

    In Australia, they have a flying version – Even worse.

  2. miguelbgood on March 7, 2017 at 3:12 pm

    There are flying cockroaches here as well, but they don’t invade in mass and stay – according to what I am told – here, like the non-flying ones in the states do.
    What works really good is putting dimetaceous earth powder around under the cabinets and where they can get in. Works on some other insects too.
    I hate ants AND cockroaches!

  3. Elaine Elizabeth Long on June 9, 2019 at 9:06 pm

    We had the cahuita army ant invasion because I stepped on to their turf and they followed me home. Soon our two story House was blackened…Everywhere ! And my feet were swelling so as not to walk We left the ants in the house to visit Jose the tico owner of Backpackers Dreams who propped me in a hammock applied leaves and a nice tea
    The ants were gone when we returned and I was GREAT ! Must have cleared me too. Happy 90th birthday to Dr E.O.Wilson author researcher lover of ants tomorrow

  4. Lucy on November 10, 2019 at 6:55 pm

    Ever consider you are poisoning yourself using all that pesticide? If the Ticos say just let them do their thing and they will leave, why not just let them? They are doing you a favor if they are removing the roaches, scorpions and other nasties you may not have even known were there.

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