Thursday, May 28, 2009

Leaf Cutter Ants and Biological Controls

On my farm here in the highlands of southern Costa Rica, we have a nice area on which we have planted citrus and avocado trees - a "frutal". But a plague of native leaf-cutter ants is devastating our new babies. My peon wants to use a powdered insecticide made especially for these ants because he has grown up using chemical as controls. We have an on-going battle about how best to protect the plants and encourage growth without using artificial and potentially dangerous herbicides and insecticides. He even dragged my to the local "cooperativa" to show me which insecticide he wanted to use. Sigh! I pointed to the words "peligro" and "venon" all over the package. Well, they've always done it that way and never bother to read the fine print (which, I must admit, is extremely small and difficult to read.

So I've been investigating biological control of native leaf-cutter ants and finding some creative possible solutions. The next big job will be to find the plants which are biological control agents and then convince Nogui to use them instead of the insecticide. IF he hasn't already purchased the insecticide and applied it without my knowledge to protect his precious frutales.

Although Nogui and I have an employee/employer relationship we have also developed rather close ties as a family unit and we share the bounty of any crops we produce. I know I can't pay Nogui what he is worth and his family is my "adopted" family. I can't let them go hungry. In this respect I am not a great business person. People are more important to me than money.

In any case I would be miserable without the loving support of my neighbors and friends here and I'm willing to yield (I'm a perfectionist by nature) to enjoy it. People are not perfect. But on the position of totally organic and natural, I am stubbornly fixed.

Anyone with a good solution to the problem of leaf-cutter ants biological controls PLEASE comment and send me links. And hurry! Nogui is getting very edgy!

Copyright Mary B. Thorman
All rights reserved


Silvana said...

Better late than never . . .I found these ideas:

Mix orange peels and water in a blender. The citrus peels act as a natural repellent for ants. Soak the mound with this concoction 1 to 2 times a day to get rid of the ants.
There are several methods of ridding your lawn or garden from the hazards created by ants beginning with organic methods. Start by drowning the ants with boiling water. Approximately three gallons of boiling water to each mound should do the trick. Follow with a natural repellent of citrus peelings and water. Blend in a blender and pour it over the anthill. Another natural remedy is to mix equal parts of sugar and borax. Place the sugar/borax mixture strategically around the yard in small containers (jar lids work just fine). The ants are attracted to the sugar and carry it back to the mound and within a week or two the borax will kill the mound. One other natural remedy is to use instant grits or cream of wheat. Sprinkle the grits over the mound. The ants will eat the grits and the grits will expand and blow up inside them. This method has been known to remove an ant hill within a day or two.

Concentrated Lemon Juice:

To keep ants away from a garden, sprinkle CONCENTRATED LEMON JUICE about the entire space, which is good for repelling ants and other insects around your fruits and vegetables.

To keep ants out of the house and/or garden, try sprinkling a bit of GROUND CINNAMON about the base of the house. The remedy is also good for the treatment of ant beds.

Chi said...

These are good ideas and work with some ants. Leaf-cutter ants, however, are a very different problem. They build very deep and complicated tunnel systems which can stretch for great distances and the queen is usually in the most inaccessible and well hidden part of the complex system. Neither boiling water nor noxious compounds reach far enough into the leaf-cutter ant's city to be of much effect. Unless the queen can be killed or sterilized, the colony keeps growing and quickly replaces even thousands of killed worker ants. The only way to control them aside from using very dangerous poisons (and this is only partially successful) is to apply an anti-fungal deep into the tunnels and to keep applying it every other day for up to several months. OR digging up the whole colony to find the queen and remove her and any eggs and larvae. This is such a tremendous task with so little chance of success, that it is never done. Research continues, however. If the colony can be destroyed before it becomes large and complex, we have a chance. But usually people don't notice the colony during the early stages of its development. When plant damage or large hills are evident, it is usually too late. Protecting the most vulnerable plants by various non-toxic means is usually the best approach. Some people plant pyrthrum flowers around fruit trees. Some peole fumigate the tunnels with smoke by starting a fire on top of the obvious entrances and exits. Weather this actually works is another question.

Isom said...

Mary, just a quick comment for now & I'll do some research since I was recently watching a documentary on these ants & how they were controlled in a diff part of the world. Unfortunately, I can't remember just what it was so must do some checking.

But for now - is there any way you can disrupt their chemical signaling? Ants use formic acid to mark their trails. On smaller problems around my place, I've used vinegar since it's acidic & messes up the formic acid trails & it's worked well. Mint, for some reason, is quite unpleasant to ants too. I went out & bought a couple of bottles of peppermint extra (since it's so strong) & mixed that into the vinegar for good measure. I wasn't about to try controlled tests to see what was most effective. I've also used that indoors when a colonly was trying to set up a nest during one particularly dry summer.

But in your case, you have a BIG problem & I doubt this would be enough. Still, perhaps as a temporary stop-gap or slow down until something else is found? Meanwhile, I'll do some checking...

(Jude from Flickr)

Chi said...

Thanks to Jude who sent me this link: . I will be trying to find jack-bean plants and/or sesame plants to try in future infestations. Actually, the planted area is surrounded by tons of organic matter since it is only a small area inside a larger mid-level rain forest. I have often wondered why so many public parks in Costa Rica have the bottom portions of their tree trunks painted white. Now I have a clue!

My own problem infestation "miraculously" disappeared while I was away for a couple of weeks. I suspect my peon bought and used the toxic insecticide against my wishes, but I have no way of proving it. He won't fess up.

Anonymous said...

Your "peon" ?

Come now, this is the 21st Century.

darce said...

I have been plagued by leafcutter ants on my one acre property in the desert southwest for two and a half years. I also want to avoid the use of insecticides/poisons. Have you had any further discoveries/successes with biological controls for leafcutter ants? Many thanks.


Anonymous said...


Can you provide more info as to what specific kind of anti-fungal should be applied and where it can be procured in Costa Rica.