meredithDear Meredith,

I saw your recent recipe for Safer Soap as an alternative to pesticides in the most recent issue of Appalachian Voice. I’ve heard about using concentrated garlic sprays to control mosquitoes as well. Will Safer Soap work for this purpose?

Thanks so much,

Amy Clark

Hi Amy,

The battle on mosquitoes has taken a serious turn this year! I think this has something to do with the incessant rain from April tomosquito sihlouette July, maybe? We’re super glad you’re looking for some natural deterrents. While Safer brand soap is a great deterrent for many pest insects, it’s not known as an effective deterrent for mosquitoes.

The garlic oil-soap spray recipe we included for Voices should work for mosquitoes. The best application would be a concentrated spray around your home, lawn, and garden. The recipe is included again with this article. If garlic sprays aren’t appealing to you, you can try soap sprays with essential oils that are known to deter mosquitoes, such as lavender, citronella, and geranium. The effectiveness of these oils seems to vary, and you may need to experiment with quantities until you get it right. For a quick first round, try a spray with equal parts water and Castile soap, and add a tablespoon of mineral oil and your chosen essential oil per gallon of mix.

Soaps and oils work by compromising the protective layer of soft-bodied insects’ skin. While research is badly needed on the effects of these deterrents on beneficial insects, preliminary studies on the west coast have shown that soap sprays and oil sprays are not harmful to beneficial insects, but are effective in controlling pest species. I’m guessing this is because there are relatively few beneficial insects that are considered soft-bodied. What I’m not sure about is the safety of oils and soaps when it comes to the eggs and larvae of beneficial insects. For example, lady bugs may be able to stand up to it, but what about their babies? At the end of the day, however, the oil-soap approach is by far one of the safest, softest approaches to pest management in the home and garden. As far as mosquitoes go, you’ll be targeting them at their pre-adult stages of life, as this is when they are most vulnerable. The soap spray should take out some adults, but know that you may be more effective over time, as you will be eradicating younger generations of the mosquito population. Keep the spraying up, in other words, and you’re more likely to see results.

When using oil and soap-based sprays, make sure you apply in the morning or evening, as the sprays can damage plant foliage when temperatures are high, or when humidity prevents the spray from drying on the leaves. If plants are very stressed, try addressing the issue (i.e. do they need a good watering?) before spraying. Make sure to coat the leaves on top and bottom, and re-apply on a regular schedule (weekly or every two weeks to start). Also, know that homemade oil soap sprays are stronger than commercially available sprays, so use extra caution to avoid foliage damage.

Good luck and happy summer!

-Meredith


Garlic Oil-Soap Spray (makes 1 pint of concentrate)

  • 25 cloves unpeeled garlic or 2 C. minced, tender garlic scapes, or 3 T. garlic powder
  • 2 t mineral oil
  • 2 t liquid castile soap
  • 2 C. warm water

Press garlic or crush it in a small food processor. Place garlic and it’s juices in a glass or jar with the mineral oil, stir it just a little, and let it stand 24 hours (longer is OK). In a bowl, mix together the garlic-oil mixture, the castile soap, and the water. Mix well and strain into a mason jar. Store in the fridge for up to 3 weeks. To use, dilute 1-2 T concentrate into 2 C. water. Spray your plants thoroughly. The garlic odor will not ruin your plants or make them taste garlicky, so spray well!

This works for cabbage loopers (adults and caterpillars), aphids, squash bugs, tarnished plant bugs, slugs, hornworms, leafhoppers, whiteflies, squash bugs, and earwigs. Will not work on larger, hard-bodied insects.

Note: If you make your treatment from dried garlic powder instead of fresh garlic or garlic scapes it will be less effective).

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Meredith Leigh

Meredith Leigh

Meredith Leigh is a die-hard advocate for good food. As a farmer, founder of a butcher shop/restaurant, and writer, she has worked on many angles of real food for over a decade. She currently teaches farming and cooking classes, consults for food and agriculture non-profits, and is writing a book about meat. Meredith has been the Program Coordinator for the Organic Growers School (OGS) Spring Conference since 2006 and was the Director and then the Executive Director of OGS for 10 years.