How to Make Homemade Sprays for Fighting Aphids (2024)

Homemade remedies for pesky insects are a longstanding tradition among organic gardeners, who have had to be creative in finding ways to battle insects and diseases without the help of synthetic chemicals. In the case of fighting aphids, or plant lice, two homemade sprays have proven very effective: tomato leaf spray or garlic oil spray. While knowing how to make and use them is important, it's equally important to understand why they work.

Tip

Before you try anything else, try simply rinsing the aphids off the leaves of affected plants. Don't use a pressure washer, just a garden hose and nozzle with enough pressure to knock the aphids off the plants without damaging the foliage. If the infestation is small, you can just wipe the aphids away with a wet cloth.

Signs of Aphids

How to Make Homemade Sprays for Fighting Aphids (1)

Before applying either of the mixtures below, be sure the insects you're fighting are actually aphids. Aphids have pear-shaped bodies, are generally about 1/16 to 1/8 inch in diameter, and can sometimes have a furry appearance. They can be a variety of colors including brown, black, red, yellow, or green and if you get up really close, you will be able to see tube-like structures at the end of their abdomens (called cornicles).

If you do have aphids, you'll find curling and stunted leaves, a sticky substance on the leaves, known as honeydew, and/or distorted flowers/fruit. You may also notice slowed growth or young plants dying altogether.

What You'll Need

Equipment / Tools

Bowl or bucket
Knife
Strainer or cheesecloth
Spray bottle
Glass or plastic jar with lid
Measuring spoons

Materials

Fresh tomato leaves
Water
Garlic cloves
Mineral oil
Dishwashing liquid

Instructions

How to Make Homemade Sprays for Fighting Aphids (2)

Tomato Leaf Spray

Tomato plants, members of the nightshade family, contain toxic compounds called alkaloids in their leaves. When the leaves of tomato plants are chopped, the alkaloids are released. By suspending the alkaloids in water, they make an easy-to-use spray that is toxic to aphids, but still safe around plants and humans.

Chop and Soak Leaves
Chop enough tomato leaves to make one or two cups and combine with two cups of water in a large bowl or bucket. Let the solution steep overnight.
Strain and Place in Spray Bottle
Strain out the leaves using cheesecloth or a fine strainer. Add an additional cup of water and pour it into a spray bottle. Be sure to label the bottle.
Use
Spray the stems and foliage of the infested plant and pay particular attention to the undersides of leaves since that is where aphids most commonly congregate.

Garlic Oil Spray

Organic gardeners have long relied on garlic as part of their pest-fighting arsenal. Garlic contains sulfur, which, besides being harmful to pests, is also an antibacterial and anti-fungal agent. The dish soap in this mixture also breaks down the bodies of soft-bodied pests like aphids.

Chop and Steep Garlic
Finely chop three to four cloves of garlic. Place in a small bowl, and add two teaspoons of mineral oil. Let this mixture sit for 24 hours.
Strain and Place in Container
Pour two cups of water into a glass or plastic bottle. Use a strainer to remove the garlic pieces and add the remaining liquid to the water. Add one teaspoon of dishwashing liquid such as Dawn. Label the container.
This mixture can be stored and diluted as needed. Add to a spray bottle before using.
Use
Before using this spray on the entire plant, test it by spraying an inconspicuous part of the plant. If there are no signs of yellowing or other leaf damage after a day or two, it is safe to use. If there is leaf damage, dilute the mixture with more water and try the test again. Once you have determined that it will not harm your plant, spray the entire plant, paying particular attention to the undersides of leaves.
Warning
Garlic oil can be harmful to beneficial insects such as ladybugs, which are natural predators of aphids. It is best to keep as many beneficial insects around as possible. This spray should only be used if you have not seen any beneficial bugs in your garden. Otherwise, you should use the tomato leaf recipe, which will not harm beneficial bugs.

Other Natural Methods
- Try to attract beneficial insects like ladybugs, lacewings, parasitic wasps, or damsel bugs to your garden with plant selections. They will attack the aphids. Plant mint, fennel, dill, yarrow, and dandelions to attract these beneficial predators to your garden.
- Avoid over-fertilizing in the garden. Too much nitrogen encourages lots of new, tender growth that aphids love.
- Cut an aluminum pie plate to fit around the base of the plant. The reflected ultraviolet rays from the sun's light cause the aphids to move away from the plant.
- Use rubbing alcohol to kill aphids. Dilute it heavily, with 20 parts water to 1 part rubbing alcohol and spray on foliage and stems.