- Author: National Pesticide Information Center (NPIC)
Acetic acid, also known as vinegar, is used in products for weed control. Many people choose it because it is natural. However, acetic acid can damage skin and eyes, especially at concentrations commonly found in weed killers.
What is the difference between acetic acid, vinegar, and horticultural vinegar?
You may know acetic acid best as vinegar. Vinegar is a solution of acetic acid in water. Acetic acid is a naturally occurring substance that is found in all living things. It is formed during fermentation. Acetic acid can also be made industrially. It is used in many industrial processes, including the manufacture of dyes, plastics, some drugs, and other industrial chemicals. It is also used in textile printing.
Household vinegar such as distilled white vinegar used for cleaning or cooking generally contains 4-6% acetic acid, which is diluted in water. Higher strength acetic acid solutions are sold for other purposes. Horticultural vinegar typically refers to a concentrated solution of 20% or more acetic acid. It is sold to kill weeds. You may find even higher concentrations of acetic acid sold in stores or online.
Are there health risks of using vinegar/acetic acid?
Acetic acid is irritating to the eyes and skin. At concentrations above those usually found in household vinegar, it can be extremely irritating or corrosive. Acetic acid can permanently damage the corneas if it gets into your eyes. It can burn skin and the tissues of your mouth and throat if you accidentally swallow it. People have had irritation in their nose, throat, and in their lungs if they breathed in enough of the vapor.
Never leave any pesticide unattended around children or pets. Never leave any pesticide in an unlabeled container. "Natural" does not mean "safe!" Remember, the dose makes the poison. The higher the concentration of acetic acid, the greater the risk.
How does vinegar/acetic acid kill weeds?
Acetic acid is a non-selective contact herbicide. It must touch the foliage of the plant in order to work. It does not damage tissue it does not touch. It does not travel throughout the plant. Acetic acid breaks open cell walls and causes cell death. The plants die by drying out.
Acetic acid breaks down rapidly in the environment. It does not leave a residue.
Acetic acid readily turns into a vapor. Like other chemicals, warmer temperatures increase volatilization, or turning into a vapor. The vapor can irritate the nose, throat, and lungs if breathed in. Prolonged exposure to high concentrations of the vapor can cause fluid buildup in the lungs.
What sort of pesticide/herbicide products contain vinegar/acetic acid?
Products containing vinegar/acetic acid that have been registered by the United States Environmental Protection Agency (U.S. EPA) as pesticides/herbicides will have a signal word and an EPA registration number on their packaging. Label information includes where and how to use the product, what precautions to take, personal protective gear to wear while using the product, and first aid instructions in case something goes wrong.
Products registered to be used as herbicides have high concentrations of acetic acid, typically 20% or more. All registered herbicides containing acetic acid have a signal word of DANGER because of the high concentrations and high toxicity. Specifically, it is because of the risks of the acid to the eyes and skin. Low concentrations of acetic acid are used in insect lures.
Acetic acid is available commercially for many purposes. Consider purchasing a product registered as a pesticide if you plan to use acetic acid for weed control. Doing so means you will have directions for use as an herbicide and information on precautions you can take to keep risks low. Products that do not have an EPA registration number and signal word are not registered to be used as herbicides and may not have appropriate safety or precautionary information for that use. Look for an EPA Registration Number and a signal word to ensure you are purchasing a registered product.
How can I reduce the risks when using vinegar/acetic acid?
- Any time you use a pesticide, always read and follow all label instructions. The label is the law.
- If the label specifies personal protective equipment, you must use that equipment.
- Wear long sleeves, long pants, shoes, socks, and gloves at a minimum whenever using any pesticide.
- Consider wearing protective eye wear and chemical resistant gloves when mixing, diluting, or applying vinegar as an herbicide because of its acidic and corrosive nature. The label instructions may require their use.
- Keep everyone else away from the treatment area until dry.
- Keep all pesticides away from children and pets. Remember that horticultural vinegar can badly damage your eyes or blind you!
- Consider integrated pest management strategies that do not use chemicals to control weeds.
For more information about pesticides and pesticide safety, visit the National Pesticide Information Center (NPIC) website at npic.orst.edu.
[Originally featured in the Summer 2024 edition of the Home and Garden Pest Newsletter]
- Author: Lauren Fordyce
- Author: Belinda Messenger-Sikes
- Author: Karey Windbiel-Rojas
You've heard of terms such as green, organic, natural, ecofriendly, and less toxic to describe pest control products and services. But what do these terms really mean? To different people, they can mean different things, creating obvious confusion. But some of these terms have specific meanings, regulations, and rules when referring to pesticides and pest control. This article aims to clarify the differences.
What is organic?
Some people think organic means no pesticides, but that is incorrect. The term organic (in the context of food production and pest control) can mean no pesticides were used, but it can also mean that only organically acceptable pesticides and fertilizers were used.
The term “organic” is regulated by federal agencies. The U.S. Environmental Protection Agency (EPA) determines whether a pesticide can be labeled organic. In addition, the United States Department of Agriculture's (USDA) National Organic Program (NOP) sets standards for organic pesticides and fertilizers. Pesticides that meet these standards may use the EPA's three leaf logo, and the NOP statement “For Organic Gardening”.
Organic pesticides may be naturally derived from plants or made from natural elements, or they can be artificially made. While organic pesticides are often less toxic to people, beneficial insects, or other organisms, some can be just as harmful as certain conventional pesticides.
If you choose to use pesticides around your home or garden and want them to be organically acceptable, look for the EPA's three leaf logo with the NOP statement “For Organic Gardening” or the OMRI seal. The Organic Materials Review Institute (OMRI) is an independent nonprofit organization that reviews and determines whether inputs (fertilizers and pesticides) are allowed for organic use in accordance with one or more specific organic standards.
What does natural mean?
You may have come across pesticide products that contain “natural” ingredients such as oils of rosemary, peppermint, or thyme. The term “natural” is not defined by any federal program or organization. For this reason, the terms “natural” or “naturally” are not allowed on pesticide labels registered by EPA.
Certain ingredients, like many plant-based oils, are exempt from EPA registration because they are considered to pose little to no risk to human health or the environment. Since EPA does not register these products, the product manufacturers may use the terms “natural” or “naturally.”
What is less toxic?
Toxicity is the ability of a chemical to injure a person, plant, or other organism. The term less toxic is not officially defined by regulatory agencies, but it generally means a pesticide or practice presents fewer risks to people, the environment, and non-target organisms (such as pollinators, fish, and other wildlife).
Less toxic pesticides often include active ingredients that are organically acceptable but may also include others that are not.
Some less toxic pesticides that are often available in stores as organic formulations include pesticidal soaps (potassium salts of fatty acids), horticultural oils (vegetable or petroleum oils), botanicals (neem, limonene, pyrethrin), minerals (diatomaceous earth, sulfur, boric acid), and biologicals (Bacillus thuringiensis (Bt), spinosad).
While you may assume products labeled organic or natural are better for you and the environment, that is not always the case. All pesticides, whether they're less toxic, natural, or organic, can be harmful to the environment and non-target organisms when not used appropriately. Review the product label and look at the active ingredients listed.
For more information about specific pesticide active ingredients, see the UC IPM Pesticide Active Ingredient database or visit the National Pesticide Information Center's (NPIC) pesticide fact sheets.
[Originally featured in the Summer 2024 edition of the Home and Garden Pest Newsletter]
/h2>/h2>/h2>- Author: Michael Hsu
Organic Agriculture Institute needs assessment refines how it can address pressing challenges
The explosive growth of organic agriculture in the U.S. – reflected in a 90% increase in organic farms from 2011 to 2021, according to U.S. Department of Agriculture statistics – has come at a cost for some farmers. With new farming operations increasing the supply of organic commodities, along with consolidation of buyers, growers report that their profit margins are not what they used to be.
Those market size considerations are among the challenges highlighted in a new report detailing the initial findings by the University of California Organic Agriculture Institute on the most pressing needs of the state's organic sector. OAI gathered and analyzed data from 423 responses to an online grower survey, over 60 interviews with stakeholders across the organic community, and additional observations from farm visits and workshops.
The report describes other frequently mentioned systemic priorities, such as maintaining integrity of the term “organic,” developing a market for organic seeds, spreading consumer awareness, and alleviating the burdens of organic certification and reporting.
Shriya Rangarajan, the postdoctoral researcher with OAI leading this statewide needs assessment, said that the reported challenges varied by organic status (fully certified, transitioning to organic, or a mixed farm with some conventional), type of crop, as well as size of the operation. She noted survey respondents were roughly representative of the sector overall – 70% small-scale growers and 30% medium and large.
“Organic is not a homogenous industry, to say the least – small growers and large growers are very different; for small growers, their challenges tend to be financial and regulatory, especially relating to certification requirements and labor,” said Rangarajan. She added that larger growers mentioned different types of challenges, weeds and pest pressures for instance, given the difficulty in controlling managing these at scale without the use or availability of organic inputs.
Organic Agriculture Institute key to sharing resources across state
Another common theme from the assessment is that the organic sector needs more accessible resources to address those myriad concerns. For OAI, established in 2020 under UC Agriculture and Natural Resources, the initial findings validated and refined the direction of its research and extension programs.
“As a new organization, we've been trying to figure out where we fit into this ecosystem and how we can support it,” said Houston Wilson, a UC Cooperative Extension entomology specialist who has served as OAI's director since its founding.
Because OAI was envisioned as a hub of resources and connections for California's organic community, Wilson and his colleagues are especially interested in understanding how its constituent members obtain information – and how OAI can improve their access.
“Growers are finding it difficult to navigate the resources that exist for organic agriculture, like technical information, financial support, compliance and certification support,” Wilson said. "While we'd like to see more resources for organic in general, those that currently exist can sometimes be hard to navigate or it can be hard to know where to go for the right thing – that became really apparent early on.”
While some producers are contacting OAI directly with their questions, Wilson is eager to develop tools and systems that can serve the community more broadly. For example, Wilson and Krista Marshall – OAI's policy and partnerships coordinator – are currently beta-testing a new map tool, built in conjunction with UC ANR's Informatics and GIS (IGIS) team. The map, expected to be ready in fall 2024, will enable users to click on their county and see all available resources related to organic agriculture.
Wilson added that OAI will have four full-time staffers by fall, further expanding its research, extension, and education efforts. After holding four field events this past year, OAI aims to increase activities in the coming year, including not just field events but also online resources, webinars and more. Also, a new training and technical assistance coordinator will be tasked with bringing Cooperative Extension advisors and other technical assistance personnel across the state up to speed on a range of organic topics, so they can more effectively answer questions from clientele in their region.
New survey aims to trace crucial organic knowledge networks
Although the OAI team has gained a sense of how information is shared across the organic community (and started to formalize those interconnections through a California Organic Agriculture Knowledge Network), they are now developing a survey to study those relationships more systematically.
“We're trying to understand what kind of knowledge resources people tap into, which is something that has come up repeatedly in our needs assessment,” Rangarajan said. “We're trying to understand who people are speaking to because, at the end of the day, organic is still a relatively small part of agriculture in California, and that makes it more fragmented. So trying to connect those different parts becomes important.”
Once Wilson has a more nuanced understanding of organic knowledge networks, he will be able to strategize and position OAI – and the UC – as a more effective partner and contributor in the sector.
“Given the history of organic, growers have had to rely on each other a lot,” Wilson explained. “We understand that the university has unique expertise to bring to the table, but we also acknowledge that there's all these other knowledge holders out there, so one of the roles that we see ourselves having is helping to facilitate those connections, strengthen them and increase the frequency of interaction.”
That may include further supporting efforts that connect transitioning organic farmers with experienced growers (a mentorship program led by Certified California Organic Farmers, or CCOF), or giving more structure to grower-researcher partnerships that can help address a host of production challenges. In OAI's grower survey, weed management topped the list, followed by water and disease issues, all exacerbated by climate variability.
“I think a lot of the real innovation changes are coming through growers experimenting with their own practice,” Rangarajan explained. “From a research perspective, one of the best ways to take this forward would be to formalize those experiments in some way so that knowledge becomes more reportable.”
And collaboration on “organic topics,” such as finding alternatives to synthetic pesticides, are a boon to the entire agricultural sector – conventional growers included.
“Everyone is trying to reduce pesticide use; everyone is trying to reduce environmental impacts,” Wilson said. “You don't have to be certified organic to benefit from organic research; these practices can be used by anyone.”
The report with OAI's initial findings on organic needs can be found at: https://ucanr.edu/sites/organic/files/396228.pdf.
/h3>/h3>/h3>- Author: Lauren Fordyce
The University of California Statewide IPM Program (UC IPM) has an exciting, newly updated resource to help you better understand pesticide active ingredients and the risks different active ingredients pose to people and the environment.
The Pesticide Active Ingredient Database is designed for urban audiences including the general public, Master Gardeners, nursery and garden center staff, pest control operators, landscapers, and more. The active ingredients included in this database can be found in many commonly available pesticide products in California. The database contains a variety of pesticide types, including insecticides, herbicides, rodenticides, antimicrobial products, and more.
Each active ingredient in the database has its own page where you can learn what it is, how it works, and what pests it can control. You can also view example products available to the general public or licensed professionals, and a table displaying the potential hazards of the active ingredient. The potential hazards table includes toxicity information for water quality or aquatic wildlife, natural enemies, honey bees, and people or other mammals. A glossary of pesticide terms is available as well to help you understand pesticide terminology.
You can use this database to compare toxicity ratings of pesticides by clicking the “Compare Risks” link or button found on UC IPM's Pest Notes fact sheets. This will help you find the least-toxic pesticide active ingredients to control a specific pest.
We hope you find this newly updated resource helpful and share with others who may be interested.
[Featured in the Summer 2024 edition of the Home and Garden Pest Newsletter]
- Posted by: Gale Perez
From the eOrganic and Performance and Economics of Electric Weed Control in Organic Perennial Crops Project:
Electric Weeding Research Updates
(Click HERE to see the presentations)
- Electric Weed Control in Orchards • Tong Zhen, Ph.D. student (Hanson Lab) at UC Davis
- Crop Safety and Weed Control in Organic Highbush Blueberries Using Electric Weeding • Luisa Baccin, Ph.D. student (Moretti Lab) at Oregon State University
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