Yardsmart: Ants are ranchers
"Agriculture is very rare in the animal world. We only know of four animal groups that have discovered agriculture: ants, termites, bark beetles and humans."
-- Entomologist Ted Schultz, Smithsonian National Museum of Natural History
Ants are farmers, or, more accurately, they're ranchers. They may decide to homestead your veggies, but it's not to feed upon these plants. Ants want to make your garden a home for their livestock. Ants favor two insects that they do not eat, but encourage to reproduce and spread into much larger colonies. Why? Because these pests that suck life out of your plants secrete a sweet liquid known as honeydew. Ants love to feed on honeydew and, therefore, they work hard to propagate ever-larger populations of honeydew-producing plant pests.
If you find ants on any of your veggies or fruit trees, they are an indicator that aphids or scale are present. This is not unusual, for these pests are everywhere in the natural world. Ants may actually transport pests from one of your plants to the next in an effort to start a new ranch. That is why ants are so problematic –– they actually help pests to spread throughout your garden. Don't try to kill the ants, look for the pests and go after them instead.
Fruit trees are common hosts of scale insects that attach themselves to twigs and branches. Ants tend these colonies to harvest every drop of honeydew that is pushed out from beneath the hard shells that make these pests so difficult to control. Often there is so much honeydew it washes down the bark and turns black as mildew grows on the residual sugars. This black sooty material is a good indicator that you have scale problems on the branches, and nine times out of 10 there will be ants present, too.
Aphids are more common in the food garden, where they were once known as "plant lice." These small pests tend to afflict soft new growth and flower buds. A few can turn into an infestation as fast as kids can pick up head lice in kindergarten.
There are many different sizes and colors of aphids. In the food garden they tend to attack plants that are stressed. For example, cabbage-family crops like kale and broccoli are prone to gray fuzzy aphids during the warmer months. This is because these are cool-season crops. When it gets hot, they tend to decline, and this weakening of the plant reduces its natural defenses. First aphids arrive, then ants show up to spread them around.
Don't run out and buy pesticides. One easy way to keep them under control on food plants is to wash the leaves top and bottom with a jet of water before sunrise or around sunset. Do this every week or two throughout the growing season to prevent population growth of aphids and scale.
For more challenging infestations, consider insecticidal soap. Soap is a neurotoxin for insects, but not for us or our pets. You can make it yourself from Internet recipes or buy a ready-to-use bottle at a home-improvement store. Never apply this in direct sunlight or you'll burn the leaves. Be sure to apply to the backs of leaves where spider mites and other pests hide.
Yet another solution is to release live ladybugs into your food-garden plants. Ladybugs feed on aphids and tiny scale babies as they move out of the mother's protective shell. If you are using this method, do not apply insecticidal soap so long as the ladybugs are still there.
Always keep a sharp eye on developing plants. Spend time among them so your vision becomes accustomed to the tiny insects that make or break your garden. Above all, don't let ants settle a homestead, because their hard work can turn those first few breeders into a giant herd of very damaging livestock.
Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com. Contact her at firstname.lastname@example.org or P.O. Box 891, Morongo Valley, CA 92256.