Controlling ants effectively means destroying the entire colony. Ants live in colonies in soil, hollow trees, walls and dry, warm places. An ant colony is often easy to spot as a mound in the lawn or elsewhere in the garden. Each colony contains male ants, ant larvae, workers and at least one queen, who lays the ant eggs. The ants you see are workers, leaving and returning to the colony with food for the queen, larvae and other ants.
To control a colony of ants, you must destroy the queen.
Never disturb a mound of fire ants. These ants give painful bites.
Pouring boiling water into a colony of ants is one of the few natural control methods that is sometimes successful. The water permeates through the mound and destroys many ants inside, and with luck the queen is also destroyed. The best time for controlling an ant colony with boiling water is after rainfall or on a cool, sunny morning, when the ants are close to the surface of the mound.
Put on rubber boots and gloves, and pour at least 3 gallons of boiling water over the mound in a steady stream.
According to the North Carolina State University Cooperative Extension, controlling fire ant colonies with 3 gallons of boiling water had a 60 percent success rate in studies.
A low-toxicity chemical, boric acid can control an ant colony within about one week. Worker ants eat the boric acid and take it back to the colony, where they feed it to the queen and larvae. Over time, the workers, queen and larvae are destroyed.
To tempt the ants to eat boric acid, the chemical must be mixed with a food the ants enjoy to make a bait, but ant species have different food preferences. Some eat sweet food and others eat food high in protein or fat. Before using boric acid as a bait, you must find out what kind of food the colony eats.
Things You'll Need
Boric acid powder
Glass jar and lid
Awl or sharp, pointed knife
Place dabs of jelly and peanut butter next to the ant mound or ant trails. Return after an hour to see which food the ants are eating.
Mix 1/2 cup of jelly or peanut butter, according to which the ants prefer, with 1 1/4 teaspoon of boric acid powder. Place the mixture in a glass jar.
Punch holes in the lid of a glass jar with an awl or the point of a sharp knife, and put the lid on the jar. Seal the edges of the lid with sticky tape.
Place the jar on its side next to the ant mound or an ant trail. You can make more bait stations to place next to other trails.
Check the glass jar the following day. If there are dead ants around the jar, make a new bait mixture with 1 teaspoon boric acid. The worker ants must survive eating the bait long enough to take it back to the colony. You may need to reduce the amount of boric acid further. If there are live ants after 10 days, increase the amount of boric acid in the bait.
If the ants can't climb the lid to reach the bait inside the jar, scratch the surface with sandpaper or a rough pebble.
Don't place boric acid bait stations in places where there are children or pets. Boric acid is low-toxicity, but it may cause some harm.
Most ants are relatively harmless in the garden, but fire ants pose a safety risk with their painful bites. Control methods for a fire ant colony include fire ant baits and mound drenches. Wear long pants, a long-sleeved shirt, safety goggles and waterproof gloves when using insecticides for fire ant control.
Apply a granular fire ant bait containing 0.015 percent spinosad in the early morning or late evening when temperatures are above 60 degrees Fahrenheit. Apply 4 tablespoons of the granules to a mound 15 inches in diameter or 4 to 6 tablespoons to a mound wider than 15 inches. Evenly sprinkle the granules over the mound and the surrounding soil 2 feet from the mound.
Don't sow seeds or plant transplants in an area treated with fire ant bait for at least one week afterward.
Pour 4 fluid ounces of a liquid insecticide containing 0.5 percent spinosad into a watering can filled with 2 gallons of water. Mix the insecticide into the water, and slowly pour 90 percent of the solution over the fire ant mound. Pour the remaining 10 percent around the perimeter of the mound.
Thoroughly rinse all equipment used to apply insecticides, and place them out of reach of children and pets. Don't use the equipment for other chores.