If something has been eating the leaves on your plants and trees, you’re probably wondering if it’s ants in your yard. The truth is that…
Ants do not eat leaves. But there are 47 kinds of ants that collect leaves, and they are known as “leafcutter ants”. These ants bite off parts of leaves and take them back to their nest, where they feed the leaves to a fungus they grow for food.
Leafcutter ants can strip a medium-sized tree of all its leaves overnight! Luckily, there are seven signs to look for if you want to know if leafcutter ants are the ones destroying your leaves, or if another insect is to blame.
Once you know you have leafcutter ants, there are a few simple steps you can take to get rid of them and save your greenery.
What kinds of ants eat leaves?
Ants are omnivores and opportunistic feeders, which means they will eat just about anything. But there is no ant that we know about that eats leaves for food.
Leafcutter ants are the only ants that bite off leaf pieces and carry them away, back to their nest. When people see these missing leaf pieces or the ants carrying leaves, they think the ants are taking the leaves home to eat.
In fact, adult ants often drink the sweet sap in the leaves and pass the sap on to other adult ants in the nest for food.
They feed the leaves to a fungus they grow inside their nest, and they feed this fungus to their young.
7 signs you have leafcutter ants in your yard
There are half-moons cut out of leaves
Leafcutter ants start damaging leaves by cutting fairly smooth half-moon shapes into the leaves with their mouths. When they find leaves that the fungus in their fungus farm likes to eat, the ants will quickly cut down the leaves in half-moon shapes until the leaves are stripped right off the stem or branch.
The following video shows how leafcutter ants cut half-moons into leaves until there is nothing left of the leaves:
Leafcutter damage is often mistaken for damage caused by leafcutter bees and sawflies.
Leaves are destroyed on particular plants and trees first
Leafcutter ants often collect leaves from certain types of plants and trees because the leaves help their fungus farm to thrive. Leafcutters won’t collect leaves that poison or harm the fungus that they grow.
Leafcutters seem to prefer collecting leaves from fruit trees, such as peach and plum trees, nut trees, blackberry bushes, ornamental plants, and cereal crops, such as corn.
The ants tend to collect or strip leaves from the plants and trees they like first, then move on to less desirable leaves if they must. For example, leafcutters will collect green leaves and seedlings before moving on to pine trees in the cooler months, when little greenery is available.
You live in an area where there are leafcutter ants
Leafcutter ants are found in warm climates, especially South and Central America, Mexico, and in some southern parts of the United States, including Texas, Louisiana, and Arizona.
If you live outside of these areas and in a cool climate, you probably don’t have leafcutter ants in your yard.
You see leafcutter ants in your yard
There are 47 species of leafcutter ants, and they don’t all look the same. But here are some common traits and habits to look for, if you are trying to identify leafcutters in your yard.
Most leafcutter ants are brown.
There are many jobs to do in a leafcutter colony, and the size of the ant depends on what work they do. The leafcutter ants you might see in your yard or on your plants are called media ants, which are 1/8 to 3/8 of an inch long.
Media ants are foragers – they leave the nest to go out looking for food when it’s not too hot outside. If you’re looking for leafcutter ants, look at night in summer and during the day in cooler months.
It’s highly unlikely that you will ever see leafcutter ants in your house, as they can’t survive in there for long and leaves are not freely available there (with food being one of the four reasons why ants come into your house).
When a forager finds good leaves to collect, it vibrates its abdomen to call other foragers to come and help collect the leaves.
If you see ants walking in a line, with each ant carrying a piece of leaf above its head, you have leafcutter ants.
You find pieces of leaves on a trail
Leafcutter ants carry leaf pieces back to their nest. They tend to follow a trail between the nest and the plant or tree they are collecting leaves from, walking back and forth along the trail many times until all the leaves are gone.
As the ants follow this trail, they often drop pieces of leaves along the way.
If you find leaf pieces that lead to the mound of an ants’ nest, you probably have leafcutter ants in your yard.
You find a leafcutter nest
Do you have the right conditions in your yard for leafcutter ants to build a nest?
Leafcutter ants need space as they build large nests underground, in well-drained, sandy soil. There are often millions of ants in a nest, along with large fungus farms.
To find a leafcutter nest, look for several mounds that are up to 2 feet high above the ground. The mounds are usually near to each other, on a south-facing piece of land near a water source.
The mounds or nest is usually within sight of the plants or trees showing leaf damage in your yard.
You find swarming ants near lights
In late spring or early summer, when the conditions are just right, leafcutter swarmers fly out of the nest to look for places to start their own nests.
If you find swarming or flying leafcutter ants with wings around outdoor lights or trying to get in through your windows at night, you probably have an established leafcutter colony nearby.
Are leafcutter ants harmful?
Leafcutter ants can cause a lot of damage to trees and plants if their colony is allowed to grow into the millions.
The damage to plants and trees is twofold:
- Leafcutter foragers can strip trees and plants of all their leaves within hours or days.
- Cuts in leaves give diseases a way in: plants and trees with leaf damage become more vulnerable to fungus and diseases, and they can die.
Leafcutter ants do not carry any known diseases and they are not dangerous to humans. Soldier ants protect the nest and will bite you if they feel threatened, but this may draw a little blood and have no other effect on you.
Leafcutter ants also do good for the environment because they trim the leaves off plants and trees, which encourages new growth. The ants also bring nutrients deep into the soil as they carry the leaves underground, where the leaves are broken up and decompose.
How to stop ants eating your leaves
To stop leafcutter ants from destroying your leaves, try the following:
- To immediately protect any plants or trees being stripped by leafcutter ants, spray the plants or trees with an insecticide like Orthene that’s available on Amazon. Be sure to spray regularly in summer, and get the spray on the top and bottom of the leaves.
- Drench the mounds of the ants’ nest with this Demand insecticide from Amazon. The ants won’t know the poison is there, and it will kill them over time as they pass over the areas with insecticide.
- Regular ant baits won’t work to kill leafcutter ants as these ants eat plant sap and fungus, not the sugary poison in baits. But there is one product that claims to kill leafcutter ants with bait, which is this Ant Block, and it has a lot of positive ratings on Amazon. Sprinkle the bait around all of the nesting mounds and wait – it will take four to six weeks to work, but you might need a second treatment about six months later.
- Spray the perimeter of your yard with a long-lasting insecticide that stops leafcutter ants from coming on to your property. This one from Bayer on Amazon is a good residual spray to try.
If you want to make your own home remedy to kill leafcutter ants, click here to get instructions on how to make your own insecticide spray with liquid soap.
Spraying leafcutter ants on plants or trees with this spray will kill the ants you see, but it won’t take care of the rest of the colony in the underground nest.