How to Make Insect Spray From Rhubarb Leaves

The leaves of a rhubarb plant will effectively battle insects like spider mites and aphids in the garden. Once you save the leaves of the rhubarb plant, they need to be steeped in boiling water to remove the oxalic acid. The oxalic acid works to kill the insects on your plants, but the leaves and solution need to be handled carefully because the acid is also dangerous to humans. The solution can be applied to your plants as needed to control the pests.

Wear rubber gloves to protect yourself from the poisonous leaves. Chop 0.454kg. of rhubarb leaves with a sharp knife.

Fill a cooking pot with 1 qt. of water.

Add the rhubarb leaves. Boil the water and leaves for 30 minutes.

Add 1 tsp of liquid dish soap to the water.

Place a bowl under a sieve. Strain the solution into a bowl, and discard the rhubarb leaves.

Pour the solution into spray bottle. Spray the solution onto the plant. Cover the undersides of the leaves, stems and canes to control the insects. Wear gloves when applying the spray to avoid contact with your skin.


Never apply the rhubarb spray on edible plants as the solution is poisonous and can cause death or severe illness when ingested. Always wash your hands and cleaning utensils with warm and soapy water after handling the rhubarb leaves.

Things You'll Need

  • Rubber gloves
  • Sharp knife
  • Cooking pot
  • 1 qt. water
  • 1 tsp liquid dish soap
  • Bowl
  • Sieve
  • Spray bottle
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About the Author

Angela LaFollette holds a Bachelor of Arts in advertising with a minor in political science from Marshall University. LaFollette found her passion for writing during an internship as a reporter for "The West Virginia Standard" in 2007. She has more than six years of writing experience and specializes in topics in garden and pets.