Getting rid of aphids is usually something you'll have to do shortly after starting a vegetable garden, but it doesn't have to be all that hard.
These annoying pests are very common, and they even attack plants indoors and in greenhouses. They are not very fussy and take up residence on many plants. Controlling aphids is a priority for vegetable growers because if left to prosper the insects can ruin large parts of the crop.
The aphids can carry viral diseases with them and help the spread of them from plant to plant.
Aphids and ants have an interesting relationship, not unlike our involvement with cattle. The ants, clever as they are, use the aphids as farm animals that they can 'milk' for a desirable, sweet substance. If the ants decide that the 'grazing' is better elsewhere they simply move their 'cattle' to another plant in your garden. And now you have an aphid infestation that you may need to do something about.
Aphid identification is fairly straightforward. They are a couple of millimeters in size, and you often see them sitting in tight clusters on the under side of leaves or along stems. Most aphids have two protrusions called 'cornicles' on their rear end. Aphids come in all sorts of colours. There are black aphids, red aphids, white, green, little orange ones with black legs and many more. Wooly aphids, also called mealy bugs, look like miniature cotton buds with wings. You may see ants running up and down the stem of the plant as they tend to their aphids.
Aphid behaviour gives us clues to how we can prevent their damage. The critters either fly on to your plants after spotting them from the air, or they're carried to suitable plants by ants. Once installed the aphids feed by sucking sap from the plant, giving the leaves a puckered or twisted appearance. After aphids find the right partner and give birth to live babies a rapidly expanding colony is the result. When it's necessary to move on some individuals develop wings to transport them further a field. In cold climates the aphids lay eggs in autumn which subsequently hatch in spring when the weather is warm enough.
Aphids produce a sweet sticky substance called 'honeydew' which gives the plant leaves a sticky feel and attracts sooty mould. It's also a highly prized ant food.
Some aphids attack roots. The 'black peach aphid' makes itself at home on the roots of stone fruit trees.
Aphid prevention goes a long way towards getting rid of aphids. The lay-out of your garden can make a difference. Long, neat and tidy rows of planted vegetables are sometimes referred to as 'landing strips for aphids'. Large blocks are easier for the insects to see from the air. Mixing and inter planting may cause the pests to overlook your patch and go to the neighbour's instead.
The health of the plants determine how great the risk of insect attack is. The right amount of nutrients and water is essential, as is suitable light and temperature. Aphid damage will happen to the not-so-healthy plant.
Keep weeds to a minimum as many species attract aphids.
Netting sounds like a good idea for getting rid of aphids, but you only need a few sneaking in while you tend to your plants, and all of a sudden you've created a nice safe environment for them to grow and prosper in - very fast. You now protect the aphids from their predators!
Natural aphid predators include ladybirds, wasps, lacewings, praying mantids and hover flies. If you resort to using sprays, these beneficial creatures will also die.
Controlling ants is essential or the aphids will just be carried around to another plant by their keepers.
Repel aphids with foil. Mulching with aluminium foil helps for some reason. Perhaps the critters don't like their own mirror image.
Plants that repel aphids include marigold, pennyroyal, anise, chives, tansy, garlic, coriander and spearmint. Growing these close to your vegetable plants will help getting rid of aphids.
Spraying with less harmful substances which don't poison the environment may occasionally become necessary to kill aphids.
Homemade aphid control sprays with ingredients such as soap, garlic, chilli, rhubarb leaves and many other concoctions help.
Don't forget that spraying with a strong jet of water on plants will often dislodge and discourage the pests.