Aphids literally suck the life from your plants, drawing out the nutrients the plants need to survive. Not only that, but they can also spread viruses from one plant to another. If not stopped, they’ll quickly overwhelm a single plant and go on to destroy others.
In the early stages, an aphid infestation isn’t hard to get under control. Even if you have an advanced infestation, though, it’s still possible to rescue your plants.
Start with a Simple Approach
If you spot just a few aphids on a plant, removing them by hand is usually enough to stop the attack. Start by preparing a bucket of soapy water. Soap dissolves the waxy coating on the aphids’ outer shells, eventually killing them. Wearing a pair of gloves, pinch the bugs off the plant’s stem, and drop them into the bucket. If there are too many aphids to remove one by one, but they’re all concentrated on a few stems or leaves, prune off the affected areas and drop those into the bucket.
In the case of a more widespread infestation, you can still physically remove the aphids, but you’ll need to take a different approach. For strong, well-established plants, a blast of water from a garden hose can do the job. This will dislodge the aphids from the plant, but it won’t necessarily kill them all, so they could show up on your plants again. Strong water pressure can damage young plants, so for these, it’s best to use another method.
For young and otherwise fragile plants you can’t blast with a hose, a simple spray with soapy water is an effective alternative. Mix up a solution of 1-quart water and 1 tsp of liquid dish washing soap, and wipe or spray this onto the parts of your plant where the aphids have accumulated. Take care to treat the undersides of the leaves, a favorite hiding spot for aphid eggs and larvae.
To really scare the aphids away, you can go a step further and add a dash of cayenne pepper to the solution. This repels the aphids that the soapy water doesn’t kill. Note that soap also kills beneficial insects such as ladybugs and lacewings, so it’s not a treatment you’ll want to use frequently.
For a gentler but more visible way to get rid of aphids, dust the affected plants with flour. The aphids will ingest the flour, which clogs their digestive system, killing them.
Treat Your Plants with Natural Sprays
Many plants produce substances to ward off aphids. Take advantage of these by using them to make sprays for your aphid-affected plants. Tomato leaves contain alkaloids that are toxic to aphids, but safe for plants. To make a tomato-leaf spray, chop one or two cups of tomato leaves and soak them in two cups of water overnight. Strain out the leaves using a strainer or cheesecloth, and pour the solution into a spray bottle. Spray the aphid-affected parts of the plant, remembering to treat the undersides of the leaves.
Garlic contains sulfur that kills not only aphids, but also harmful fungi and bacteria. To make a spray from this herb, chop three or four cloves of garlic and let them soak in three tablespoons of mineral oil overnight. Strain out the garlic, pour the oil into a pint of water, and pour that mixture into a spray bottle. Before treating the whole plant, spray a small part to see how the mixture affects the plant. If after three days, you see no damage such as yellowing or curling leaves, you can safely spray the whole plant.
Neem oil, which comes from the seeds of the Indian neem tree, can also help you fight off an aphid attack. You can find this oil at garden centers. Mix a solution of 1 tsp neem oil and 1 quart water. For a more effective spray, add 1/3 tsp insecticidal soap or dishwashing soap. The spray doesn’t store well and should be used within 8 hours, so start with a small batch.
You’ll most likely need two or more applications to rid the plant of aphids. For the first application, spray enough of the solution onto the plant to soak the leaves. Wait a week, then lightly spray on a second application. If the plant has suffered repeated infestations, spray it with this solution once every week or two weeks to keep the bugs away.
Work With Nature
If your garden has suffered repeated aphid infestations, making some improvements to the environment will be a more effective long-term solution than sprays. Ladybugs and lacewings both eat aphids. Buying live ladybugs and lacewing eggs is the fastest way to bring these beneficial insects into your garden. Hoverflies also enjoy chowing down on aphids. They can’t be shipped, but you can attract them by planting oregano, garlic, yarrow, and bachelor buttons.
Plants in the allium family, including onions, garlic, chives, and leeks repel aphids, so consider planting these around your garden and flower beds. Some fragrant herbs, such as mint, dill, oregano, and fennel do double duty by warding off aphids while attracting ladybugs.
Aphids love nasturtium and mustard plants, so avoid placing these near delicate plants that could be easily damaged by an aphid attack. This doesn’t mean keeping them out of the garden entirely, though. By placing them away from other plants or near large, strong plants such as sunflowers, you can create an aphid trap. Aphids will gather where they can be easily removed, rather than spreading throughout the garden.
Because some birds, such as wrens, chickadees, and titmice, consume aphids, it’s worthwhile to make your garden bird-friendly by adding sources of shelter, food, and water. These can take the form of unpruned shrubs and smaller trees, a pond or birdbath, and bird feeders. In the feeder, use a seed blend designed for the types of birds you want to attract.
Aphids are an annoyance nearly every gardener faces from time to time, but minor infestations won’t cause lasting damage as long as you take steps to treat them as soon as you notice them.
If you have a more advanced infestation, it might take a few weeks to clear up, but by applying your chosen treatment regularly, you’ll eventually have aphid-free plants. Once you’ve gotten rid of the aphids, keep them from coming back by growing aphid-repelling plants and attracting beneficial insects and birds to your garden.