In recent years, the UC Statewide IPM Program has received an influx of questions from UC Master Gardeners and the general public about homemade pesticides. Below is our official statement on homemade pesticides and guidance for UC Master Gardeners when discussing pesticides with clientele.

A brief definition of homemade pesticides: Mixtures formulated with household ingredients (i.e. dish soap, vinegar, garlic, cooking oils, etc.) with the intent to use for killing, controlling, reducing, or repelling a pest (insects, mites, pathogens, weeds, vertebrates) are considered pesticides. Homemade pesticides might also include mixtures of commercially available pesticides (for example neem oil) with household ingredients.

UC IPM statement on homemade pesticides: Homemade pesticides, as defined above, should not be recommended or suggested by UC Master Gardeners to the public as a method for controlling pests. Unless included within UC ANR peer-reviewed publications, homemade pesticides generally have not been studied in replicated research trials and therefore have not been scientifically proven to effectively control pests. The ingredients used in homemade pesticides vary widely, and their effects on the environment (natural enemies, pollinators, water quality, soil quality) and humans have not been studied or proven to be safe or less-toxic.

What should UC Master Gardeners do? UC Master Gardeners share science-based, unbiased information and resources with the public. This includes UC ANR publications and other resources on the UC IPM website that have been written by UC academics and peer-reviewed for accuracy. On page 222 of the UC Master Gardener Handbook, it states, “All pesticide recommendations to the public must be recommendations published by UC. Do not recommend home remedies for use as pesticides…”?

When discussing pest control strategies with the public, UC Master Gardeners should provide options and resources. This follows UC IPM's integrated approach, which seeks to solve pest problems while minimizing risks to people and the environment.

In the process of presenting pest solutions, you may suggest pesticide active ingredients but not specific products. These must be referenced in the UC IPM Pest Notes for the pest you are dealing with. For example, if a client is looking for a pesticide to use to control aphids, you may suggest horticultural oils or insecticidal soaps because these pesticides are listed as options in the Pest Notes: Aphids publication. When “oils and soaps” are mentioned in UC IPM publications, we are referring to commercially available oils and soaps that are formulated specifically for use as pesticides- not household oils and soaps meant for cooking, cleaning, or other purposes.

Homemade pesticides are not advised for several reasons:

1. They are not registered by the U.S. EPA and are not in compliance with the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). Pesticides are legally required to be registered by the U.S. EPA for sale and use or comply with FIFRA exemptions.
2. They do not come with detailed product labels like commercially available pesticides. Pesticide product labels have instructions for use, including the amount to use, frequency of applications, how soon after application you can harvest crops, and whether the product can even be used on edible crops. Safety and disposal information is also listed, including what to do if someone is exposed and needs to seek medical attention.
3. Pesticide product labels are legal documents that users are required to read and follow. If someone gets harmed while using a labeled product, they can seek legal action. If they did not use the product according to label instructions, they would likely lose their case. Homemade pesticide recipes and advice shared online and through social media, vary from one to another and do not include these important details that prevent harm or litigation. Home remedies shared by UC Master Gardeners that are not backed by research could subject the University to litigation if a user experiences damage or injury from advice given.
4. Some household products included in homemade pesticide recipes include additives and ingredients that are synthetically made that could harm the environment because they were not formulated to be used outdoors, on plants, or in a manner different from the ingredient's intended purpose. Most dish soaps are not naturally occurring substances nor are they biodegradable. They can contain detergents and degreasers that are harmful to groundwater and aquatic and soil organisms.

A note about acetic acid, or vinegar: Pesticides with the active ingredient acetic acid and labeled as herbicides can be used to control small or young weeds. However, household acetic acid (vinegar) products labeled for kitchen or cleaning uses, should not be used as herbicides. Keep in mind that products containing more than 10% acetic acid are dangerous and often these pesticides will have the signal word DANGER as high concentrations of acetic acid is corrosive and can cause irreversible eye and skin damage.

If you have any questions about pesticides or would like information about pesticide training for your program, contact the UC IPM Urban Team at ucipm-community@ucanr.edu.

                                                                        -- Lauren Fordyce & Karey Windbiel-Rojas, UC IPM

References

https://edis.ifas.ufl.edu/publication/PI288

https://www.epa.gov/minimum-risk-pesticides