How To Make Garlic Spray For Plant Pests

Can you use a garlic spray for pests? A popular part of folklore, it was believed the pungent smell of garlic confused the noses of vampires, lycanthropes, and other creatures of the night.

Not surprisingly, garlic actually does fend off a wide range of monsters, especially those with six legs.

Hand presses on fresh garlic dispenser
Does a garlic spray for plant pests work? | worklater-DepositPhotos

Garlic protects both plants and humans against a wide range of problems, including bacteria, fungi, insects, and virii.

Does Garlic Work To Control Pests On Plants?

Garlic functions primarily as a pest repellent, but that doesn’t mean it can’t also kill some pests.

In terms of lethality, garlic has several compounds which harm or kill many detrimental garden pests.

These compounds include:

  • Allicin (when crushed)
  • ASAL
  • Diallyl disulfide
  • Diallyl trisulfide

Scientific research suggests many of the lectins and lectin-like compounds (including ASAL) might interfere with the life cycle of insects.

They can affect feeding by affecting vital digestive proteins and disrupt egg distribution. 

They are also known to damage the sensory receptors in insects.

Harmful insects generally avoid plants with “garlic breath”, while beneficial insects are unhindered.

This means you can fight or prevent an infestation without sacrificing pollinators, making garlic sprays an excellent weapon for organic gardeners as a safe, natural pesticide and fungicide.

What Garden Pests Does Garlic Control?

The different compounds in a garlic spray for pests can have different effects, depending on the target species.

ASAL, found in the sap and juices of garlic, is toxic to:

Diallyl trisulfide has proven to be twice as effective as pyrethrum and is highly toxic to the overwintering pear psyllid.

A Garlic spray is also highly effective in either killing or repelling:

Oddly enough, some of these pests will prey on garlic plants but cannot handle allicin or other byproducts found in a garlic spray.

Both rodents and deer hate the smell and will generally leave treated plants alone.

Recipes for Natural Sprays

There are a massive number of great recipes out there for garlic-based sprays.

Some will use individual cloves of garlic, while others use the entire head.

Remember that size does matter – the smaller the cloves, the more potent they’ll be.

Garlic should be used in conjunction with one or more other substances to make a more effective spray, including:

  • Dishwashing soap (or castile soap) – Liquid soap helps hold the spray on plants and allows the spray to get into insects’ respiratory systems (Dawn is a great choice due to its low toxicity to animals).
  • Essential Oils – Oils such as eucalyptus, mint, or neem serve as additional repellents and may also disrupt the nervous or reproductive systems of some pests.
  • Hot Pepper – Fresh or ground peppers such as cayenne contain capsaicin (the substance that gives them heat) which serves as an irritant to both insects and mammals but won’t affect birds.
  • Mint – Peppermint and spearmint attract beneficial insects but repel flies, mosquitoes, and spiders; while pennyroyal mint repels fleas and ticks.

The following recipes are just a few examples to get you started.

Be sure to experiment making your own concoctions to get the ideal results for your own unique pest problems.

Garlic-Mint Spray

Ingredients:

  • 2 heads garlic with the garlic cloves separated and peeled
  • 3 cups mint leaves
  • 2 tablespoons cayenne pepper
  • 1 tablespoon Dawn

Pulse the mint and garlic in a food processor. Add the mix to 12 cups water in a pot along with cayenne. Bring to a boil, then let it cool overnight. Strain the mixture into spray bottles, adding the dish soap last.

Garlic-Pepper Spray

Ingredients:

  • 1 head garlic (small)
  • 1 jalepeno or 1 tablespoon cayenne

Making The Garlic Mint Spray

  • Liquify the head of garlic in a blender, adding in the pepper towards the end.
  • Add 2 cups of water and pulse to mix.
  • Pour into a covered glass container and let it sit 24 hours in a dark space.
  • Add more water to make 1 gallon
  • Strain through cheesecloth into your sprayer
  • Store the rest in the fridge

How To Apply and Use Garlic For Pest Control?

Pretty much all garlic sprays use the same methods of application.

Shake the spray bottle well to ensure it hasn’t separated.

Be sure to spray the entire plant, choosing evening or an overcast day to prevent sunburn to the leaves.

Also cover a bit of the ground around the plants and fence off if you have outdoor pets.

Reapply every few days as needed and after it rains.

Note that food plants should be harvested a few days after the spraying and washed thoroughly to avoid unwanted seasoning.

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