General good housekeeping can help prevent infestations. Before planting, be mindful of the space you leave between crops and shrubs. Weeds and plant debris can facilitate a bad pest infestation.
Companion planting with strong-smelling herbs such as Basil, Chive, Allium and mint are believed to deter aphid activity. Nasturtium is a brilliant buffer plant which can attract insects away from vegetables and fruits.
Aphids aggregate in areas of new growth, so be sure to check in all the nooks of plants, especially under leaves!
For heavier infestations, treat plants with a strong jet of water to dislodge the insects from the plant.
Alternatively, use a light, soapy mixture sprayed on the plant or even just squashing them.
A mixture of tomato leaf and distilled water is believed to deter aphids. Once the leaves are drained, dilute the remaining mix with 1-2 cups of water. Tomato plants contain the same allergens as nightshade. It's not advised to use this method if allergic to nightshade.
Garlic or chilli-based sprays diluted with water can act as a natural insect repellent.
Placing ant traps near infested plants will help to control secondary ant infestations.
Aphids possess an array of natural enemies (ladybirds, wasps and lacewings, to name a few!). Attract beneficial insects by planting a selection of indigenous plants, incorporating an insect hotel, or by letting some bits of the garden grow wild.