Aphids are a common garden pest. They do damage by sucking the plants they infest and by excreting sticky honeydew. The following are tips to prevent and control aphids.
Avoid over fertilizing: Aphids prefer tender new growth that appears in profusion with over fertilized plants. Use slow release fertilizer.
Monitor: Check your plants once a week. If you see ants climbing up a plant they are most likely harvesting the aphids’ honeydew. Putting sticky tape around the trunk of plants can stop ants.
Spray with water: Spraying aphids with water can dislodge them from the infested plant and knock them off where they will be less likely to re-infest.
Natural predators: There are natural predators such as lady beetles, lacewings, syrphid flies, and various parasitic wasps. Lady beetles are often available commercially, however they tend to disperse in a few days.
Insecticidal soap: A mixture of two tablespoons of mild dish soap with luke warm water in a spray bottle is effective in cleaning aphids from plants. The soap dissolves the aphids waxy protective coating and causes them to dehydrate. Also mixing three tablespoons of vegetable or horticultural oil with luke warn water and a few drops of dish soap can be effective to clog the aphids breathing spiracles. Spray once a week and alternate between methods.
These methods only take care of mature aphids, not those in eggs. Repeated applications should eventually rid your plants of the little pests.