Cedar Oil as an insecticide - Ask Extension
Hello OSU Extension Service - I live in Cincinnati (Hamilton County) and plan to mix my own cedar oil insecticide to apply to the yard and around the ...
Knowledgebase
Cedar Oil as an insecticide #757716
Asked June 22, 2021, 1:34 PM EDT
Hello OSU Extension Service - I live in Cincinnati (Hamilton County) and plan to mix my own cedar oil insecticide to apply to the yard and around the house this summer. My home is well-maintained, over 100 years old, and built into a hillside surrounded by a lot of trees and vegetation. The air and ground hold quite a bit of moisture here, and there are abundant populations of insects, spiders, chigger mites, mosquitoes and other undesirables. The east side of Cinti is also home to European wall lizards (Podarcis muralis) which regularly sun themselves on my back patio and front porch, and occasionally make their way into the house! Bug and lizard activity is huge this year - more than usual. I've already had it with the chiggers and mosquitoes, If I can get the overall insect population under control the lizards will likely move on in search of a better food supply. Anyway, I've researched several commercial (expensive) cedar products online (Cedarcide, Wondercide, etc.) and found similar ingredients lists for each... 85% Texas cedar oil, 15% ethyl lactate or SLS. One also includes sesame oil @3.5%. Since I also aim to try Neem oil this year (control lawn/leaf fungi as well as bugs), I'm wondering about mixing neem oil with the cedar to save time in spraying. Will doubling up affect the effectiveness of one or the other? Finally, I'm considering adding a bit of clove oil to my cedar mix (eugenol content to help with knockout of bugs), but have also read that clove can act as an herbicide and kill plants (NOT what I want). Speaking with an advisor experienced in 'natural' pest control would be welcome. I can be reached at<personal data hidden>. Thank you! Amy Flanary
Hamilton County Ohio
Expert Response
Dear Ms. Flanary,
My name is Ann Chanon, and I am an Extension Educator. Your question was assigned to me because Master Gardener Volunteers do not make chemical recommendations. We recommend homeowners use a variety of other techniques including biological (for example Bt products), mechanical, and cultural practices such as removing standing water to reduce the mosquito breeding grounds to deal with their pest issues rather than insecticides (either synthetic or natural). While cedar oils products are being promoted and sold as alternative insecticides there has been little testing on their effectiveness on your target species or their possible negative impacts on non-target species like pollinators. Essential oils are volatile and they work most commonly as contact killing agents only meaning that the insect must come in direct contact with the oil for the product to have its insecticidal properties, so re-treatment may be needed. I cannot comment on application rates or frequency. I was not able to locate any information on the effect of blending various oils together. These products could have a synergistic, antagonist or neutral effect on one another. Without scientific data, again I cannot comment. I would be very cautious if you are going to use any of these products around plants of horticultural value. Standard horticultural practices would dictate. Avoiding the use oils on plants that tend to be oil-sensitive, including but not limited to Junipers and cedars, Maples (particularly Japanese and red maple), Redbud, Smoke tree, Spruce (particularly dwarf Alberta spruce). Avoid drift onto sensitive plants. Do not apply when temperatures are excessively high (above 86 degrees F) or low (below 40 degrees F). Do not apply oils if plant tissues are wet or rain is likely. These conditions inhibit oil evaporation. Do not apply oils in combination with sulfur or sulfur-containing pesticides because they can react with oils to form phytotoxic (plant damaging) compounds. I also found " Eugenol is rapidly absorbed by skin, is toxic to human skin cells, and can cause severe eye irritation. Applicators should wear protective eye wear and water proof gloves for handling and spraying." To my knowledge we do not have anyone connected with OSU Extension that has a focus on 'natural' pest control.
Respectfully,
My name is Ann Chanon, and I am an Extension Educator. Your question was assigned to me because Master Gardener Volunteers do not make chemical recommendations. We recommend homeowners use a variety of other techniques including biological (for example Bt products), mechanical, and cultural practices such as removing standing water to reduce the mosquito breeding grounds to deal with their pest issues rather than insecticides (either synthetic or natural). While cedar oils products are being promoted and sold as alternative insecticides there has been little testing on their effectiveness on your target species or their possible negative impacts on non-target species like pollinators. Essential oils are volatile and they work most commonly as contact killing agents only meaning that the insect must come in direct contact with the oil for the product to have its insecticidal properties, so re-treatment may be needed. I cannot comment on application rates or frequency. I was not able to locate any information on the effect of blending various oils together. These products could have a synergistic, antagonist or neutral effect on one another. Without scientific data, again I cannot comment. I would be very cautious if you are going to use any of these products around plants of horticultural value. Standard horticultural practices would dictate. Avoiding the use oils on plants that tend to be oil-sensitive, including but not limited to Junipers and cedars, Maples (particularly Japanese and red maple), Redbud, Smoke tree, Spruce (particularly dwarf Alberta spruce). Avoid drift onto sensitive plants. Do not apply when temperatures are excessively high (above 86 degrees F) or low (below 40 degrees F). Do not apply oils if plant tissues are wet or rain is likely. These conditions inhibit oil evaporation. Do not apply oils in combination with sulfur or sulfur-containing pesticides because they can react with oils to form phytotoxic (plant damaging) compounds. I also found " Eugenol is rapidly absorbed by skin, is toxic to human skin cells, and can cause severe eye irritation. Applicators should wear protective eye wear and water proof gloves for handling and spraying." To my knowledge we do not have anyone connected with OSU Extension that has a focus on 'natural' pest control.
Respectfully,
Dear Dr. Chanon,
Thank you for your reply. Your advice and expertise are appreciated. We have no standing water serving as breeding grounds for mosquitoes. As for adjusting the physical environment surrounding the home (shady woods, steep hillsides with dense groundcover), keeping areas clean and adequately trimmed is what I've done so far, yet I'm sure that space is ideal for robust populations of 'bugs.' Thanks for bringing BT to my attention - I will read up on that. Anecdotally, I've used essential oils extensively for around 30 years for a variety of purposes - personal, health, home, etc. and have been very satisfied with outcomes. I do appreciate your perspective and cautions.
OSU extension services have been a valuable resource over the years - I'm an Ohio State graduate (1980s College of Biological Sciences) and my father-in-law retired from a career as OSU professor of agronomy (soil science). Thanks for all you do in serving your community!
Amy Flanary
Dear Ms. Flanary,
First, thank you for your kind words. I is always great to meet someone who was attending college at about the same time. I earned my undergrad degree from OSU in '89 from the College of Ag.
It is helpful to know more about the site. I am glad to know that there is no standing water as that is the number one reason for high mosquito populations. However, that also rules out the use of Bt. Bt is usually applied in what is called a "dunk" a round cake about 2" in diameter. They can be used in open rain barrels, decorative ponds and the like to stop the larval stage of mosquitoes.
I wish I could locate more information of the use of essential oils in the landscape. If I find anything I will definitely drop you an email. I know essential oils are expensive so one thought is to try the cedar oil in a small area and observe its efficacy.
Best wishes as you work to develop an insect management strategy that works for you and your landscape.
Please continue to reach out to OSU Extension if we can be of further assistance.
First, thank you for your kind words. I is always great to meet someone who was attending college at about the same time. I earned my undergrad degree from OSU in '89 from the College of Ag.
It is helpful to know more about the site. I am glad to know that there is no standing water as that is the number one reason for high mosquito populations. However, that also rules out the use of Bt. Bt is usually applied in what is called a "dunk" a round cake about 2" in diameter. They can be used in open rain barrels, decorative ponds and the like to stop the larval stage of mosquitoes.
I wish I could locate more information of the use of essential oils in the landscape. If I find anything I will definitely drop you an email. I know essential oils are expensive so one thought is to try the cedar oil in a small area and observe its efficacy.
Best wishes as you work to develop an insect management strategy that works for you and your landscape.
Please continue to reach out to OSU Extension if we can be of further assistance.
