Carpenter ants are a sure sign of wet wood
Stephen in Gaithersburg writes: "We have LOTS of ants in our front and back yard - - both the normal small brownish ants and larger black ants (not sure if they are just black ants or carpenter ants). It's the black ants that are my particular problem, as they are actually building a small mound in our backyard."
Well Steve, scientists estimate that there may be more ants on the planet than any other type of creature, and they come in an astonishing array of shapes and sizes. Your large black mound-building ants are somewhat unusual in our area (but not unheard of), and luckily for you, are not carpenter ants.
Carpenter ants don't build mounds or live in lawns. Instead, they search for and ingest damp cellulose, like wet cardboard and rotting wood. Big black carpenter ants in your home are a warning sign that you either have something like a lot of wet cardboard boxes lying around or rotting wood somewhere.
In such cases, it's important to remember that the carpenter ants are not the problem -— they won't attack sound wood. Instead they're more of a homeowner's wet wood alarm, alerting you to the fact that you need to repair or replace the damaged wood that attracted them in the first place, or get the old wet boxes out of that soggy cellar.
Take a different approach with mound-building ants
Back to Stephen in Gaithersburg and his "large black ants building a small mound in the backyard."
He says, "We have three kids, so I don't want to use a toxic ant-killer. Is there a natural organic way to get rid of the ants? I read about using boric acid…"
Well Steve, boric acid traps are the sure cure for small indoor ants, but mound builders are a very different species. And although your black mound-building ants don't deliver a painful venomous sting like the very dangerous mound-building fire ants down south, I'd recommend the same remedy.
First, drench the mound with an orange-oil-based natural liquid insecticide such as Orange-Guard. Apply it in the cool of the early morning, when the queens will have been moved to the top of the mound to get warm.
Wait a week and then apply an organic insecticide whose active ingredient is spinosad, which is a naturally occurring soil-dwelling organism that is one of the best and most effective modern insect controllers. There are many brand names; look for "spinosad" as the active ingredient on the label.
This combination of a knock-down drench and follow-up long-acting natural pesticide will eliminate the queens (each mound may contain several of the egg-laying female monarchs) without any danger to other creatures -- like your children!
'Everyday ants' may be keeping termites at bay
Karen, who lives "on a few acres of paradise in Brookeville," writes: "Is there a natural way to reduce ants in my lawn? I'm on well water so I'd rather not use a poison pesticide. I don't need to get rid of them, just reduce their numbers -- they're the harmless little black ants and they're not in the house."
Well Karen, as you note, these garden-variety ants are harmless. They're even thought to be beneficial, as they aerate the soil and keep termites at bay. The ants raid termite colonies to devour their young, and termites will not set up shop in an area where their nursery is going to be under constant attack.
So be on accelerated termite watch if you do knock their numbers down, which you would do with the same kind of store-bought boric acid bait traps sold for indoor ant control. Just put the traps under cardboard boxes -- not out in the open. This will help prevent the liquid bait from drying out quickly, and much more importantly, keep bees away from the sweet, sugary bait.
Red thread to be expected on cool, wet lawns
Connor in Fairfax writes: "My front yard is suffering from Red Thread. What do you recommend I do? The lawn is tall fescue. I personally mow it at 3.5 inches, feed twice a year (spring and fall), and water once a week with my irrigation system."
Red thread is a disease that mostly attacks fescue lawns. It's more pink than red, often a bit web-like in appearance, and is generally only a problem in cool, wet spring seasons -- such as the one we just had. Watering during this time of biblical deluge certainly aggravated the problem.
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