One of the many things local farming ants do is tend herds of aphids. Ants protect their aphid herds from predators, and there are many. They do this by bringing them into underground aphid corrals and moving them to better feeding spots. Doesn’t that sound cute and nice?
It does sound cute and nice until you find out that the reason your artichokes are doing badly is that aphids are draining the sap out of your plants. Grr! Where’s the neem oil?
Aphids are tiny insects, from pinhead size to an eighth-inch across. They are typically black or green. They cluster on new shoots and the underside of leaves. They are clumsy and sluggish, but reproduce at a very fast rate. And they can do some serious damage. Aphids secrete honeydew that tends to mold, which causes additional damage to plants, and also can harm young birds who are starting to leave a nest in an aphid-infested tree—Alameda Animal Control had to rescue a young Cooper’s Hawk who got stuck in honeydew-soaked leaves last summer.
Aphid predators include ladybugs, soldier beetles, parasitic wasps, small lizards, and small birds. Being clumsy and sluggish, aphids have few defenses against these predators—that’s where the ants come in.
Ants, though tiny, are excellent warriors, and the honeydew aphids produce is a favorite food source. Their aggressiveness and ability to coordinate gives them the ability to ward off beneficial bugs, and sometimes birds and lizards. Farming ants move aphids from one spot to another, remove diseased aphids, and “milk” the aphids by stroking their abdomens. This stroking encourages the aphids to secrete honeydew, which the farming ants lap up and then share with the rest of the colony. “Farmed” aphids are healthier, escape predators easier, and reproduce prolifically.
As far as the gardener is concerned, the end result of all this sophisticated endeavor is that the plants that you are working so hard to grow may be overrun with aphids, which will eventually kill the plants. Convincing those ants and their aphids to go elsewhere involves making life so miserable for both of them that the ant colony will pack up and move. When they do, the ants will take aphid eggs with them so they can start a new “farm.” The remaining aphids will be picked off by ladybugs and the enraged gardener.
You need different eradication methods for ants and aphids.
Getting rid of ants
The ants you see above ground are part of a colony. If you use pesticides to kill those ants you see, the colony will just send out more. The best solution is to set out ant bait, which is ant food mixed with an ant poison. Borax is a natural mineral that is not highly toxic to mammals, but is deadly to ants. Borax does not kill ants immediately. Ants find the bait, carry little bits of it into the nest, and that poisons the rest of the colony.
Ants do not eat plain borax, so the mineral has to be mixed with something ants are attracted to, such as sugar. Ant stakes containing borax are inexpensive and contain the bait so that it doesn’t get into the soil. Ant stakes can also be positioned or hidden so that children or pets don’t eat the contents—it will make them sick.
You can make your own ant bait with one part borax (available in the laundry section of large supermarkets and online) and three parts sugar. Add enough water to make a paste. Mix thoroughly. Put out little containers with the bait where the ants are congregated. Make sure children and animals can’t get into your homemade ant bait.
Getting rid of aphids
It’s easier to get rid of aphids than ants. Start with a hard stream of water. Make sure you wash off the bottom of leaves, where aphids tend to hide, then spray as much of the plant as you can reach with either neem oil or insecticidal soap.
Check your plants on a regular basis. Aphids and ants—especially ants—are persistent little critters, but if you keep up your anti-ant campaign, they will move elsewhere.
References:
Gardening Knowhow: Ants and Aphids
Farmer Ants and Their Aphid Herds
Margie Siegal is a long term gardener in Alameda and a supporter of Alameda Backyard Growers. Reach her via [email protected].
