Frequently Asked Questions
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How to Identify a Japanese Beetle
Q: What does a Japanese beetle look like?
The Japanese beetle has several distinct characteristics that separate them from all other insects in the region. Below, is a graphic that shows the difference between the Japanese beetle and other look alike insects.
The Japanese beetle has several distinct characteristics that separate them from all other insects in the region. Below, is a graphic that shows the difference between the Japanese beetle and other look alike insects.
Japanese beetles in Oregon
Q: What is an eradication project?
An eradication project may be put in place following a detection of a new invasive species to remove all life stages (pest adults, larvae and eggs) from the area and stop the pest from becoming established. Methods for eradication vary based on the biology and characteristics of the pest. Without eradication, the pest would remain in the state indefinitely. It is best to detect invasive species as early as possible. Sometimes, early detection methods will detect as few as 1-2 individuals. Risk models and biological experts help to make the call whether an eradication project is necessary to protect the state from the devastating effects of an invasive species. Prevention and early detection programs are a critical part of our state’s defense against invasive species.
The Japanese beetle population in Cedar Mill, Bonny Slope, Oak Hills, and Bethany of Washington County was small enough when detected that eradication may be possible.
Q: What is an invasive species?
According to the Oregon Invasive Species Council:
“Invasive species are animals, plants, and microorganisms that are not native to Oregon and once here can reproduce so vigorously that they replace our native species. They pose a threat to key sectors of Oregon's economy that depend upon natural resources and native ecosystems.” Learn more about invasive species in Oregon here.
Q: How do we know that Japanese beetle is a problem?
Like many invasive species, Japanese beetles outside of their native habitat do not have predators in the United States to balance out and stabilize their population. Throughout the Eastern and Midwestern United States, JB populations create large-scale destruction to garden plants and agricultural crops. Because the beetle is a serious threat to many of Oregon’s thriving industries, including nurseries, turf grass, and specialty crops, ODA is working hard to contain the JB population through quarantine and treatment. The fight to eradicate and prevent invasive species such as JB is an effort to protect Oregon’s agricultural livelihood.
Q: How would Japanese beetle affect crops, gardens, and forests?
This invasive pest can be destructive in multiple life stages. As an immature “grub” it feeds on the roots of grasses, limiting the plant’s ability to acquire water, creating dead patches of grass or turf. As an adult, JB feeds on leaves creating a pattern known as “skeletonizing”. The feeding results in the defoliation of the plant. Roses, grapes, fruit trees, and berry plants are highly susceptible to this type of damage. Defoliated plants not only lose their leaves, but are are more susceptible to disease and stress, have higher death rates, and lose the ability to photosynthesize. Without photosynthesis, essential ecosystem services such as purifying air, maintaining water quality along streams and rivers, and mitigating extreme temperatures (via shading) are affected.
Q: How do I know if I have Japanese beetle on my property?
In the fall, winter and spring, Japanese beetle is an immature “grub”, and feeds on the roots of grasses, limiting the plant’s ability to acquire water. Look for dead areas of turf or grass as a sign that Japanese beetle grubs might be present. In the summer, you may find Japanese beetle adults feeding on leaves, fruits or flowers (Japanese beetles love roses!), see this look-alike guide for tips on identifying Japanese beetle.
If you live outside the treatment area and think you have JB on your property, contact the ODA team to improve the detection process.
Note: Japanese beetle are often confused with boxelder bugs. If it’s late autumn and you have hundreds of beetles coming into your home, these are not Japanese beetles. Boxelder bugs are native to North America. These bugs are not invasive nor are they poisonous, but they can be a nuisance as they seek out warm places to stay for the winter. To learn more about boxelder bugs and how to prevent them from coming into your buildings, read this boxelder bug info page maintained by University of Minnesota Extension.
Q: How did Japanese beetles come to Oregon?
JB was first found in the United States in a nursery in New Jersey in 1916. Since then, JB populations have spread throughout the East coast and Midwest, causing devastating impacts in home gardens and agricultural crops. Japanese beetles most likely were brought to Oregon by someone moving from an affected area with a potted plant. JB eggs and larvae live in soil and can be easily transported by accident, hidden from the view deep in the soil.
Plants, grass clippings, sod, and other yard and landscaping materials can easily transport JB from one region to another. That’s why ODA has created a yard debris quarantine for part of Washington County. For more information, check out our quarantined Yard Debris & Landscaping FAQ section (below).
Q: Where is the Japanese beetle in Oregon?
There have been three separate beetle detections in Oregon in recent years:
An eradication project may be put in place following a detection of a new invasive species to remove all life stages (pest adults, larvae and eggs) from the area and stop the pest from becoming established. Methods for eradication vary based on the biology and characteristics of the pest. Without eradication, the pest would remain in the state indefinitely. It is best to detect invasive species as early as possible. Sometimes, early detection methods will detect as few as 1-2 individuals. Risk models and biological experts help to make the call whether an eradication project is necessary to protect the state from the devastating effects of an invasive species. Prevention and early detection programs are a critical part of our state’s defense against invasive species.
The Japanese beetle population in Cedar Mill, Bonny Slope, Oak Hills, and Bethany of Washington County was small enough when detected that eradication may be possible.
Q: What is an invasive species?
According to the Oregon Invasive Species Council:
“Invasive species are animals, plants, and microorganisms that are not native to Oregon and once here can reproduce so vigorously that they replace our native species. They pose a threat to key sectors of Oregon's economy that depend upon natural resources and native ecosystems.” Learn more about invasive species in Oregon here.
Q: How do we know that Japanese beetle is a problem?
Like many invasive species, Japanese beetles outside of their native habitat do not have predators in the United States to balance out and stabilize their population. Throughout the Eastern and Midwestern United States, JB populations create large-scale destruction to garden plants and agricultural crops. Because the beetle is a serious threat to many of Oregon’s thriving industries, including nurseries, turf grass, and specialty crops, ODA is working hard to contain the JB population through quarantine and treatment. The fight to eradicate and prevent invasive species such as JB is an effort to protect Oregon’s agricultural livelihood.
Q: How would Japanese beetle affect crops, gardens, and forests?
This invasive pest can be destructive in multiple life stages. As an immature “grub” it feeds on the roots of grasses, limiting the plant’s ability to acquire water, creating dead patches of grass or turf. As an adult, JB feeds on leaves creating a pattern known as “skeletonizing”. The feeding results in the defoliation of the plant. Roses, grapes, fruit trees, and berry plants are highly susceptible to this type of damage. Defoliated plants not only lose their leaves, but are are more susceptible to disease and stress, have higher death rates, and lose the ability to photosynthesize. Without photosynthesis, essential ecosystem services such as purifying air, maintaining water quality along streams and rivers, and mitigating extreme temperatures (via shading) are affected.
Q: How do I know if I have Japanese beetle on my property?
In the fall, winter and spring, Japanese beetle is an immature “grub”, and feeds on the roots of grasses, limiting the plant’s ability to acquire water. Look for dead areas of turf or grass as a sign that Japanese beetle grubs might be present. In the summer, you may find Japanese beetle adults feeding on leaves, fruits or flowers (Japanese beetles love roses!), see this look-alike guide for tips on identifying Japanese beetle.
If you live outside the treatment area and think you have JB on your property, contact the ODA team to improve the detection process.
Note: Japanese beetle are often confused with boxelder bugs. If it’s late autumn and you have hundreds of beetles coming into your home, these are not Japanese beetles. Boxelder bugs are native to North America. These bugs are not invasive nor are they poisonous, but they can be a nuisance as they seek out warm places to stay for the winter. To learn more about boxelder bugs and how to prevent them from coming into your buildings, read this boxelder bug info page maintained by University of Minnesota Extension.
Q: How did Japanese beetles come to Oregon?
JB was first found in the United States in a nursery in New Jersey in 1916. Since then, JB populations have spread throughout the East coast and Midwest, causing devastating impacts in home gardens and agricultural crops. Japanese beetles most likely were brought to Oregon by someone moving from an affected area with a potted plant. JB eggs and larvae live in soil and can be easily transported by accident, hidden from the view deep in the soil.
Plants, grass clippings, sod, and other yard and landscaping materials can easily transport JB from one region to another. That’s why ODA has created a yard debris quarantine for part of Washington County. For more information, check out our quarantined Yard Debris & Landscaping FAQ section (below).
Q: Where is the Japanese beetle in Oregon?
There have been three separate beetle detections in Oregon in recent years:
- Cedar Mill, Bonny Slope, Oak Hills, Bethany Raleigh Hills, Cedar Hills and Orenco neighborhoods of Washington County. The population that was detected in 2016 in Washington County has grown into the largest and most widespread ever detected in Oregon. This website was developed to address this complex and large-scale eradication project. Although the origin is uncertain, ODA suspects that this population was likely started by a potted plant moved into the neighborhood from a JB infested area.
- Oakland, OR. The population in the historic town of Oakland, OR was detected in 2017. In total, 10 beetles were detected. In 2020, no beetles were detected. This population was likely started by a potted plant moved into the neighborhood from a JB infested area.
- Portland International Airport, OR. There is a persistent threat of new introductions through high-traffic airports carrying cargo from Japanese beetle infested areas. The Portland airport requires treatment each year to manage the threat of new introductions. ODA has been successful for over 40 years in keeping this threat from expanding to other areas of the state.
Treatment & Consent
Q: How do you treat an area for Japanese beetle?
What is being treated? For specific information about what treatment is, please visit our Treatment page.
Q: Where is the treatment area?
Explore the map of the 2023 Japanese beetle treatment area using the button below. Outside of the treatment area designated in Washington County and NE Portland, treatments have occurred in Oakland, OR and the Portland International Airport in recent years. Learn more under the Q: "Where is Japanese beetle in Oregon?"
What is being treated? For specific information about what treatment is, please visit our Treatment page.
Q: Where is the treatment area?
Explore the map of the 2023 Japanese beetle treatment area using the button below. Outside of the treatment area designated in Washington County and NE Portland, treatments have occurred in Oakland, OR and the Portland International Airport in recent years. Learn more under the Q: "Where is Japanese beetle in Oregon?"
Instructions for using the map:
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Q: I live in or near the treatment area, how can I help?
Cooperation from those in the treatment area is critical to protect Oregon’s gardens and agricultural economy! Here’s what you can do to help:
Q: How do I consent to treatment?
If you live within the treatment area, you will receive a notice from the ODA with details about the project, including a consent form. Treatment for Japanese beetle begins each year in April. Please return your completed consent form as soon as possible once you’ve received it.
Q: How will I be notified?
You will be contacted at least 72 hours in advance to inform you what day your property is to be treated. Your notification will be via the phone number, text number, or email you provide us on your consent form.
Q: I've already received the granular treatment, why would I need a second treatment?
In the 2019 eradication, we started a supplementary foliar application of Acelepryn for properties within a smaller high beetle density area within the larger treatment area. The foliar spray targets the adult stage of Japanese beetle, while the granular treatment targets the larvae. Targeting the beetles at two life stages will help further reduce the populations, and also protect your garden from damage caused by adults.
Q: I live in or near the treatment area, how can I help?
Cooperation from those in the treatment area is critical to protect Oregon’s gardens and agricultural economy! Here’s what you can do to help:
- Report insects that you suspect could be Japanese beetle, if found OUTSIDE of the treatment area, to the ODA.
- Report any extensive beetle damage to lawns, roses, grapes, fruits, or other trees and shrubs, if found OUTSIDE of the treatment area, to the ODA.
- Cooperate with ODA survey staff when they request permission to place traps on your property during the summer.
- Comply with quarantine regulations that stop the movement of plants and soil from infested eastern states, unless the material is certified by state agricultural officials to be free of Japanese beetle or has been properly treated to eliminate any beetle life stages.
Q: How do I consent to treatment?
If you live within the treatment area, you will receive a notice from the ODA with details about the project, including a consent form. Treatment for Japanese beetle begins each year in April. Please return your completed consent form as soon as possible once you’ve received it.
Q: How will I be notified?
You will be contacted at least 72 hours in advance to inform you what day your property is to be treated. Your notification will be via the phone number, text number, or email you provide us on your consent form.
Q: I've already received the granular treatment, why would I need a second treatment?
In the 2019 eradication, we started a supplementary foliar application of Acelepryn for properties within a smaller high beetle density area within the larger treatment area. The foliar spray targets the adult stage of Japanese beetle, while the granular treatment targets the larvae. Targeting the beetles at two life stages will help further reduce the populations, and also protect your garden from damage caused by adults.
Health & Safety
Q: What is the pesticide that the ODA will treat my land with, and will it harm humans, pets, or other insects?
Acelepryn G® is a targeted larvicide that kills certain pests in their larval state in the soil. This is a “reduced risk” pesticide and is not considered to be a health threat for humans, pets, and other insects that don’t go through a larvae stage in treatment areas (including pollinators) when applied correctly.
According to the label, “Acelepryn G is recommended for Integrated Pest Management programs on turf and landscape ornamentals because it does not directly impact natural arthropod predator and parasitoid populations including ladybird beetles.” Since the treatment targets certain pest larvae in the soil, the treatment with Acelepryn G® has no adverse effects on pollinators when applied according to the label instructions. The common lawn pest, crane flies, are a targeted pest of Acelepryn G.
Q: What effect does it have on pets?
AceleprynG does not present a hazard to humans, or domestic animals, according to the EPA. The harm that a pesticide can cause humans and animals is known as toxicity. EPA has determined that AceleprynG falls into a low toxicity category by all routes of exposure. It is unlikely that even direct exposure to chlorantraniliprole, when used according to directions on the Acelepryn G’s label, will result in adverse health effects to humans or animals. There are no caution words on the product label and there is no re-entry period. Which means once the product is placed on the ground, people, kids, and pets can re-enter the yard and walk on the grass. Although we do recommend watering your lawn first to help dissolve the granules which improve the efficacy of the treatment, and to exercise an over-abundance of caution. For more information, please visit: https://oda.fyi/JBHealth
Q: Why do I have to keep my pets inside all day?
After driving, the greatest threat to the safety of our crew is being bitten by dogs. Due to the current Covid-19 pandemic, our protocols (such as if we are allowed to knock on residentials doors right before treatment) are fluid and subject to change. This is why we request that dogs be kept inside the day of treatment, to try an minimize this risk in case we are not able to knock on your door before treatment. If you are not able to keep your dog inside on the day of treatment, let us know by phone, email, or by writing a note on your consent form and we can make arrangements to call you right before treatment so dogs can be put inside.
Q: Will my vegetable gardens or blueberry bushes be treated?
Vegetable gardens, blueberry bushes, and other edible shrubs or plants are not subject to treatment at this time.
For more information about the larvicide Acelepryn G®, please visit the Oregon Health Authority’s Q&A page.
Acelepryn G® is a targeted larvicide that kills certain pests in their larval state in the soil. This is a “reduced risk” pesticide and is not considered to be a health threat for humans, pets, and other insects that don’t go through a larvae stage in treatment areas (including pollinators) when applied correctly.
According to the label, “Acelepryn G is recommended for Integrated Pest Management programs on turf and landscape ornamentals because it does not directly impact natural arthropod predator and parasitoid populations including ladybird beetles.” Since the treatment targets certain pest larvae in the soil, the treatment with Acelepryn G® has no adverse effects on pollinators when applied according to the label instructions. The common lawn pest, crane flies, are a targeted pest of Acelepryn G.
Q: What effect does it have on pets?
AceleprynG does not present a hazard to humans, or domestic animals, according to the EPA. The harm that a pesticide can cause humans and animals is known as toxicity. EPA has determined that AceleprynG falls into a low toxicity category by all routes of exposure. It is unlikely that even direct exposure to chlorantraniliprole, when used according to directions on the Acelepryn G’s label, will result in adverse health effects to humans or animals. There are no caution words on the product label and there is no re-entry period. Which means once the product is placed on the ground, people, kids, and pets can re-enter the yard and walk on the grass. Although we do recommend watering your lawn first to help dissolve the granules which improve the efficacy of the treatment, and to exercise an over-abundance of caution. For more information, please visit: https://oda.fyi/JBHealth
Q: Why do I have to keep my pets inside all day?
After driving, the greatest threat to the safety of our crew is being bitten by dogs. Due to the current Covid-19 pandemic, our protocols (such as if we are allowed to knock on residentials doors right before treatment) are fluid and subject to change. This is why we request that dogs be kept inside the day of treatment, to try an minimize this risk in case we are not able to knock on your door before treatment. If you are not able to keep your dog inside on the day of treatment, let us know by phone, email, or by writing a note on your consent form and we can make arrangements to call you right before treatment so dogs can be put inside.
Q: Will my vegetable gardens or blueberry bushes be treated?
Vegetable gardens, blueberry bushes, and other edible shrubs or plants are not subject to treatment at this time.
For more information about the larvicide Acelepryn G®, please visit the Oregon Health Authority’s Q&A page.
Quarantine & Yard Debris
Q: Is the free quarantine drop site available in 2024?
No, unfortunately the free yard debris drop site will not be available in 2024. From 2017 to 2022, a quarantine against the Japanese beetle has been in place in Oregon. During that time, the State has provided yard debris collection and disposal services to the public in quarantined areas free of charge. Due to recent budget constraints, the Oregon Department of Agriculture (ODA) will be pausing the free yard debris collection and disposal services until further notice. Instead, ODA is prioritizing its trapping and pesticide applications in infested areas. Best Buy in Town will continue to recieve your yard debris materials, but the drop service is no longer free at this time.
No, unfortunately the free yard debris drop site will not be available in 2024. From 2017 to 2022, a quarantine against the Japanese beetle has been in place in Oregon. During that time, the State has provided yard debris collection and disposal services to the public in quarantined areas free of charge. Due to recent budget constraints, the Oregon Department of Agriculture (ODA) will be pausing the free yard debris collection and disposal services until further notice. Instead, ODA is prioritizing its trapping and pesticide applications in infested areas. Best Buy in Town will continue to recieve your yard debris materials, but the drop service is no longer free at this time.
Q: Is it safe to put yard debris in the curbside yard debris container after it was treated with Acelepryn G?
Yes, please place directly in the curbside bins. The yard debris is considered hazardous due to the possible presence of beetles, not the larvicide.
Q: Does composting kill Japanese beetles?
Certain hot composting conditions could kill the beetle but it is not guaranteed, which is why all yard debris from the treatment area will be transferred directly to the Hillsboro Landfill for deep burial.
Q: Where can I get a trap for my property?
If you have reason to believe your property or location is particularly hospitable to Japanese beetle and would like to have a trap, contact ODA.
Q: I live in the treatment area and participate in my local garden clubs’ plant swap, can I swap plants from my yard if no beetles are visible?
No. You should not swap plants from the treatment area. JB can be moved in a variety of ways, including in potted plants. It is likely that the current population was introduced from a potted plant that was moved into the neighborhood from a JB infested area outside of the state.
Yes, please place directly in the curbside bins. The yard debris is considered hazardous due to the possible presence of beetles, not the larvicide.
Q: Does composting kill Japanese beetles?
Certain hot composting conditions could kill the beetle but it is not guaranteed, which is why all yard debris from the treatment area will be transferred directly to the Hillsboro Landfill for deep burial.
Q: Where can I get a trap for my property?
If you have reason to believe your property or location is particularly hospitable to Japanese beetle and would like to have a trap, contact ODA.
Q: I live in the treatment area and participate in my local garden clubs’ plant swap, can I swap plants from my yard if no beetles are visible?
No. You should not swap plants from the treatment area. JB can be moved in a variety of ways, including in potted plants. It is likely that the current population was introduced from a potted plant that was moved into the neighborhood from a JB infested area outside of the state.