What to Spray on Lettuce for Insects

Growing lettuce at home allows you to enjoy the leafy green vegetable fresh from the garden. Lettuce needs protection from insects that enjoy feasting on the green foliage. Protect the plants with natural sprays or control large infestations with chemical pesticides. Since commercial pesticides are a cause for health concerns, only apply them when necessary. You need to control pests effectively because they will continue to multiply and they often carry diseases that can kill garden crops.

Insecticidal Soap

Pour 1 1/2 tsp of a liquid dishwashing detergent into a spray bottle. Add 1 qt. of cool water to the soap. Stir the soap and water gently to prevent causing soap suds to form. Spray the insecticidal soap over the lettuce when the temperature remains below 32.2 degrees Celsius. Applying the soap in hotter weather can burn the foliage on the lettuce plants. The soap will kill the insects on the lettuce by dehydrating the pests. Insecticidal soap works well to protect lettuce against lace bugs, aphids, earwigs and spider mites.


Hook up the garden hose and place a nozzle onto the end of it. Spray the lettuce foliage with a sharp and steady stream of water from the garden hose. The water will remove aphids from the lettuce leaves. Spray the lettuce in the morning so that the foliage can dry during the day. Spray the lettuce leaves when the plants need water. Avoid spraying the lettuce every day because you can overwater the crops and make them susceptible to root rot.

Vinegar Solution

Combine one part of white distilled vinegar with three parts of cool water inside a spray bottle. Add 1 tsp of liquid dish detergent and swirl the bottle to mix the ingredients well. Spray the solution directly onto the lettuce leaves to control insects. The vinegar spray effectively will keep slugs, moths, ants and other pests away from your lettuce. Apply the vinegar spray weekly to protect the lettuce. Avoid increasing the amount of vinegar in the solution because the acidity may damage the lettuce.

Commercial Pesticides

You may need to apply chemicals to lettuce when large insect infestations occur. Identify the insects that have invaded the lettuce plants. Purchase a chemical pesticide safe to use on the lettuce and locate one that will specifically control the insects. Soil-injected and granular insecticides work best for controlling insects. Check the lettuce plants daily to monitor the infestation. Always follow the directions on the pesticide to ensure that you apply it properly.

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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.