They’re a menace. A total nightmare in ornamental and edible gardens alike. The bane of many gardener’s lives, these tiny pests wreak havoc, and can weaken or destroy huge numbers of crops. But don’t despair and reach for the expensive, harmful, and pretty useless chemical pesticides just yet – we’ve got quite a few different ways to control aphids naturally. Our methods are easy, inexpensive, organic, and safe.
Before we get into how to control aphids naturally, let’s look at a few of the common sign of aphid infestation:
- Yellowing leaves
- Stunted and distorted leaves and growth
- Failure to thrive
- Death of young plants
- Black, sticky substance on stems and leaves
- Obvious presence of large numbers of aphids
- Excessively large any population
- Generally unwell plants and the spread of viruses and infections
Now you know what to look for, let’s find out how to control or kill aphids naturally. Did you know that aphids are notoriously hard to kill with chemical pesticides? They are particularly resilient to those expensive synthetic products that indiscriminately kill every insect, poison wildlife, leach into your soil and your crops and pose a health hazard to your family. Because aphids are so resilient, often gardeners are forced to buy the strongest product they can find, and make multiple applications of it – and it still won’t be that effective. So, using natural methods is a better option for your health, your pets, your wallet, and the environment – and it’s more effective. It’s important to note that natural options for anything, from cleaning to health and pest control usually requires a multi-pronged approach for the best results – so you may have to employ a few of these natural pest control methods, particularly if an infestation is already present.
1. Use Natural Predators
Predatory insects like ladybirds and lacewings, as well as hoverflies and predatory wasps, adore aphids, and will devour huge quantities. You can attract these insects by using the right companion planting combinations and some species, like ladybirds and lacewings, are available commercially. Ideally, release commercially acquired predators before there’s a major infestation, or soon after you’ve used one of the other natural aphid control methods. Because you know that there’s a high probability that at least a portion of your plants will be attacked by aphids, make sure you plan ahead. Practice companion planting to attract beneficial insects that will control aphid populations before they can get too established.
2. Kill Ants
That’s right. Kill ants to control aphids. Why? Because ants “farm” aphids. They have a fascinating, if intensely annoying, symbiotic relationship. The aphids produce a sweet, sticky substance called honeydew as they feed, and the ants simply adore it. They can’t resist it. So, they protect aphids, killing predators like ladybirds and offering care, removing dead aphids and any that show signs of illness. They literally farm them like humans farm cattle. Ants are well-known for their chemical production – scent trails, etc. – but studies from the Royal College of London, reported by Science Daily, show that they release chemicals that tranquilize and subdue aphids, to keep them where the ants want them. Some species of ants even bite the wings off the aphids, to stop them flying away, and the chemical footprint of some ants even stunts or restricts the growth of aphid wings. It’s a fascinating, slightly disturbing, and really irritating example of mutualism. So, kill the ants, reduce the aphid population. Buy ant-eating nematodes to reduce the numbers of ants or, as long as the nest isn’t near your plants, pour boiling water into the nest to kill the queen. You can also make your own garlic fire spray or use diatomaceous earth – but remember that control methods like these don’t discriminate – they’ll kill useful bugs too, so be selective about what you use, where. Ideally, find the nest and kill those little blighters at the source.
3. Reflective Mulch
Nobody is quite sure why, but using reflective items like foil as mulch around the base of your plants seems to confuse and repel aphids. It’s exceptionally effective, and used in conjunction with other items on this list dramatically reduces aphid numbers.
4. Grow Trap Crops
This is another form of companion planting. Trap crops are plants which are irresistible to specific insects – in this case, aphids. This is a particularly useful method in edible gardens. If you know a certain crop has a high risk of getting aphid-ized (yes, I totally made that word up), then plant species that aphids adore far away from your edible crops. The aphids then head for your trap crops instead of your food crops. These are some of the best trap crops for aphids:
5. Plant Members of the Onion Family
Members of the onion family – including garlic and leeks, have a distinctive aroma and aphids hate it. So use these species as edible companion plants. Place them all around the garden and in close proximity to any plants that are at risk of aphid infestation.
6. Water Pressure
For reasonably mature plants, spraying them with a hose with a sprayer attachment forcibly removes the aphids. You’ll need to do this roughly three times a week to get an infestation under control, then once or twice a week as and when you spot gatherings of the little swines.
These are our favorite ways to control aphids naturally. Keep an eye out, or sign up to our newsletter, as we’ll be publishing our garlic fire spray recipe soon! Do you know of any natural ways to control aphids that we’ve missed? Please leave us a comment and share your knowledge.