Organic Strategies for Ant Control © Frances Michaels

Appearance
Ants are insects in the Order Hymenoptera, and it should be recognised that they can be beneficial as well as pests. They will kill and eat any insect they find, including fleas, fly larvae and termites. In some areas they are an important part of the natural processes of soil aeration and organic matter breakdown. Management programs should aim to keep them out of the house without eliminating them from all other environments.
Lifecycle
Ants are social insects and live in colonies. Usually there are 3 distinct castes: workers, queens and males. Some species also have a soldier caste. Eggs are laid by the queen, then develop into larvae, pupate and become adults.

Indoors
Ants invade houses searching for food and are more of a nuisance than a danger, and they certainly do not warrant the use of highly toxic insecticides. Use soapy water sprays to kill invading ants until you can undertake more permanent solutions.
Proper Storage of Food
Food should be kept in containers that close tightly. Pet food should not be left out overnight or place it in a bowl of soapy water to prevent ant access.
Storage of Organic Waste
Compost buckets need to have tight fitting lids. Bottles, cans and wrappings that have food particles clinging to them should be washed out before storage for recycling.
Cleaning
A vacuum cleaner is useful to remove crumbs from corners and cracks in the floor, as well as inside cupboards.
Sealing Cracks
Find out where the ants are entering the house and then use a silicon caulk to block their passage. If possible, place boric acid or diatomaceous earth in the cracks before closing.

Outdoors
Try to tolerate ants outdoors as they are part of the environment and control many pests such as termites, cockroaches, fleas and flies. Increasing the humus levels and using mulch will discourage ants in the garden. Biting ants close to the house, children's play area or gardens may need to be controlled using the Spraying Treatment outlined below.
Flooding
Flooding with water is useful to rid ants from plant pots.
Spraying Treatment
Make up a spray containing 500 ml of water, 60 ml of kerosene, 60 ml of liquid detergent and 40 ml of vegetable oil, shaken together. Spray a circle about 0.5 m radius from the nest entrance. Pour a cup of water slowly into the nest entrance, wait a few minutes and then spray all the ants on the surface with the homemade spray or a pyrethrum based spray. Repeat this procedure every 2 - 3 days until the ant population declines. Additionally lay 3 - 6 baits as described below, around the nest.
Baits
Use boric acid and sugar solution bait as a least-toxic control. To make the bait mix 3 cups of water, 1 cup sugar and 4 level teaspoons of boric acid. Half fill a small screw-topped jar with cotton wool, saturate with bait, screw the lids on tightly, seal with adhesive tape, pierce several small holes in the lid to allow the ants access but prevent removal by larger animals. Keep away from children and pets. This takes a few weeks to wipe out a colony but is more effective than using highly toxic pesticides that only kill the foraging ants, not the colony. Some ants will prefer a mint jelly or peanut butter bait.
Sticky Barriers
Use horticultural glue, such as Tree Guard Glue around tree trunks to aid in the biological control of scales, aphids and mealybugs, as ants patrol trees defending these pests from attack by their natural enemies, in order to maintain their supply of honeydew.
It is highly recommended to band the tree prior to applying the glue especially for young, thin-barked trees and smaller fruit trees. By banding you protect the tree and lengthen the life of the glue application. In addition, re-application or removal is far easier. You can use Tree Wrap, cling wrap, duct tape, or masking tape to band the tree.

Suggested Products:
Amgrow Tomato and Vegetable Dust
Horticultural glue
Pyrethrum