-
Pest SolutionsPESTS + WEEDSUSING PESTICIDES OR HERBICIDES?
I should be a large image.
Insect Pests in Lawns
Many species
Updated Mar 16, 2023
Make a Positive Identification
Insects Can Damage Lawns, But Damage Could Be Caused by Other Factors
- Insects are not the most common cause of lawn damage.
- Poor lawn care is the most likely cause of unhealthy or dying lawns.
- Lawn diseases and dog urine damage look similar to insect damage.
Inspect Your Lawn for Insects and Their Damage
- Look for direct signs of insects and their damage as described in this article.
- Insect damage usually begins in small, scattered patches. These may merge into larger damaged areas.
Grow a Healthy Lawn to Minimize Damage from Insects
You can minimize insect damage to your lawn by growing healthy, robust grasses. See Prevent Lawn Problems to learn more.
Crane Fly
Species: Crane Fly
Whitney Cranshaw, Colorado State University, Bugwood.org
Common Crane Fly (Tipula oleracea) & European Crane Fly (T. paludosa)
- Crane flies are common in Western Oregon. They have also been found east of the Cascade Range.
- Adult crane flies are long-legged, two-winged flying insects as shown in the photo. They resemble large mosquitos.
- Crane fly adults emerge from the soil starting in July through mid-October. Crane flies overwinter as larvae in the soil.
- Adult crane flies don’t damage grasses.
Species: Crane Fly
"Leatherjacket" by Simon is licensed under CC BY-NC 2.0.
Crane Fly Larvae
- Crane fly larvae are 1–1.5 inches long. They have leathery skin. Crane fly larvae are called leather jackets.
- They feed on crowns and roots of lawn grasses from winter into spring.
- Grass usually recovers when larvae stop feeding.
- Weeds may grow in weakened areas and bare ground areas.
Species: Crane Fly
“Crane fly scouting (Kowalewski)” by Oregon State University is licensed under CC BY-NC 2.0.
How to Identify Crane Fly Damage
- Crane fly larvae cause lawn grasses to thin in early spring. That’s the time when your lawn should be starting vigorous growth.
- You might see birds such as starlings and crows search for larvae in lawn areas.
- If you suspect crane fly larvae are damaging your lawn, remove a 1-foot-by-1-foot patch of grass as shown in the photo.
- If you see 25–50 or more crane fly larvae in the area, then consider control methods.
Billbug
Species: Billbug
Kansas Department of Agriculture, Bugwood.org
Billbug (Sphenophorus spp.)
- Billbugs occur both west and east of the Cascade Range. They cause problems mainly in inland areas of the Pacific Northwest.
- Kentucky and annual bluegrass lawn grasses are most susceptible to billbug damage.
- These insects also damage tall fescue, Chewings fescue, and perennial ryegrass.
- Adults are about 0.375-inch long and black in color. They have a distinct snout as shown in the photo.
Species: Billbug
David Shetlar, The Ohio State University, Bugwood.org
Billbug Larvae Damage Grass Roots
- Larvae are white with a brown head, and about 0.25-inch long when mature. The photo shows a billbug larva (white) causing feeding damage to grass roots.
- Larvae feed on grass roots. They cut off roots from the plant.
- Larvae reach damaging size in the summer.
Species: Billbug
David Shetlar, The Ohio State University, Bugwood.org
How to Identify Billbug Damage
- Look for brown, thin, dying grass in small, irregular spots.
- The damage can spread to patches many feet wide, as shown in the photo.
Cutworm
Species: Cutworm
W.M. Hantsbarger, Bugwood.org
Black Cutworm (Agrotis ipsilon) & Variegated Cutworm (Peridroma saucia)
- Cutworms are moth larvae that feed on grasses and other plants. They cut plants off at the base, as shown in the photo.
- They can occur in large numbers that cause significant damage to turf grass areas.
- Damage from cutworms to home lawns is rare. Significant damage occurs more often on golf courses.
- Cutworm damage is more common in older lawns made of creeping bentgrass.
Species: Cutworm
James Kalisch, University of Nebraska, Bugwood.org
Cutworm Larvae Feeding Damage
- Larvae are up to 1 inch long with a small head as shown in the photo. Their color is nearly black to grey-brown or multicolored.
- Feeding damage causes small, irregular spots in the lawn. The damage can spread to many feet across in width.
Tips for Cutworm Control
- Hand-pick and destroy larvae.
- Control weeds around your lawn. Cutworms also feed on a wide range of plants.
Sod Webworm
Species:
Mark Dreiling, Bugwood.org
Cranberry Girdler (Chrysoteuchia topiarius) & Larger Sod Webworm (Pedasia trisecta)
- Adult sod webworms are also known as “lawn moths.” There are two distinct species that resemble each other.
- The photo shows an adult cranberry girdler moth. They are slender and grayish-white to tan in color. They have a distinct snout.
Species: Sod Webworm
Whitney Cranshaw, Colorado State University, Bugwood.org
Sod Webworms Larvae Damage Grasses
Sod webworm larvae (shown in photo) cause irregular brown spots in lawns. The larvae chew off leaf blades at the base.
Species: Sod Webworm
M. R. Bush, Washington State University
Sod Webworm Larvae
Sod webworm larvae are cream-colored with a double row of dark spots down their backs. They are 3/4-inch long.
White Grub
Species: White Grub
Whitney Cranshaw, Colorado State University, Bugwood.org
White Grub (Scarabaeidae family of beetles)
- The photo shows a scarab beetle adult (left) and a white grub larva (right). Adults lay eggs that hatch into larvae.
- Many beetles in this group eat decaying plant material and animal dung. They are beneficial to the natural environment.
- White grubs don’t cause significant damage to lawns.
Species: White Grub
David Cappaert, Bugwood.org
How to Identify White Grub Damage
- The larvae have robust, cream-colored bodies as shown in the photo.
- Larvae of several species of scarab beetle feed on roots of lawn grasses.
- White grub larvae cause patches of dead or dying grass. Feeding damage occurs from spring through fall. Damage peaks in June-July.
- Peel back turf to determine whether many white grub larvae may be in the soil and causing damage.
Species:
diane555, iStock
Invasive Species Alert—Japanese Beetle
- Japanese beetle (Popillia japonica) is an invasive insect species in the Scarabaeidae family of beetles.
- Adult Japanese beetles (shown in photo) cause significant feeding damage to hundreds of plant species.
- Japanese beetle larvae cause significant damage to grasses in lawns, parks, and golf courses.
- Japanese beetles pose a major threat to plant nurseries, orchards, field crops, parks, golf courses, and landscapes in the Pacific Northwest.
Japanese Beetle in Oregon
Learn about Japanese beetle in Oregon. See Japanese Beetle PDX (Oregon Department of Agriculture).
Insect Pests in Lawns Benefits
- Most types of insects found in lawns are harmless or beneficial.
- Lawn pest insects provide food for many other animals and birds.
Insect Pests in Lawns Risks
- Depending on the insect species, they may damage the roots of grasses or cut off grass leaf blades at the base.
- Animals and birds are attracted to the lawn by insects. Those predators may cause further damage by digging in search of their prey.
Risk Card
Does it cause harm?
Adults & Children
None
Property
Low
Affects lawns
Pets
None
Annoyance
Some
For manicured and high-traffic lawn areas
Environment
Helpful
Many lawn insects are part of the food chain. Birds and other wildlife feed on them.
Action Optional
For high-maintenance lawns, consider taking action after identifying lawn-damaging insects
TAKE ACTION?
Insect pests are not a common cause of residential lawn damage. People have different tolerance levels.
What damage do insects in lawns cause?
Certain insect species may damage or even kill lawn grasses. If insect damage recurs or if the damage becomes extensive, action may be necessary for high-maintenance lawns.
Do I need to take action?
Before applying an insecticide, establish whether insects are the cause of the damage. Determine which insect before deciding on any response.
What if I do nothing?
- Damage to lawns from insects is often tolerable.
- For manicured lawns, consider control options only after you’ve confirmed the identity of an insect pest.
Prevent Lawn Insect Pests
OSU Turfgrass Management Program
Maintain a Healthy Lawn
- Maintain the right growing conditions needed for strong, healthy turfgrasses. Healthy lawns resist insect pest problems.
- Lawns change over time. After you sow lawn seed or lay sod, a mixture of desired turfgrasses and broadleaf weeds, grassy weeds, and moss will evolve.
- Soil drainage, soil fertility, sunlight, water stress, and how the lawn is cared for and used all influence how your lawn will look over time.
- Set realistic expectations for your lawn. Match the lawn standards you want to maintain with the right maintenance schedule.
- If the quality of your lawn doesn’t match your standards, consider a lawn renovation.
- For more information, see Prevent Lawn Problems.
Solutions for Insects in Lawns
- Prevent lawn insect problems by maintaining a healthy lawn. Renovating your lawn will get rid of insect damage. Then establish a lawn maintenance routine that helps maintain a robust lawn to minimize future damage. See Prevent Lawn Problems.
- Inspect grass roots and/or perform a drench test to detect lawn insect pests.
- Insecticides (insect killers) are only effective if applied at the right time of year and according to label instructions for a specific type of lawn insect pest.
- Many insecticides also kill beneficial insects. Only use them as a last resort.
- If you choose to use an insecticide, products derived from biological sources have minimum impacts on beneficial organisms and the environment.
NEED HELP?
Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.
Jump to
| Method | Does it work? | Is it safe? | Recommendation |
|---|---|---|---|
A Maintain A Healthy Lawn |
Very effective |
Low risk |
Recommended |
B Monitor for Insects |
Effective |
Low risk |
Recommended |
C Biological Insecticide Products |
Effective |
Low risk |
Recommended |
D Neem Oil & Plant Essential Oils |
Effective |
Moderate risk |
Use if Necessary |
E Broad-Spectrum Insecticides |
Effective |
High risk |
Use if Necessary |
F Systemic Insecticides for Lawns |
Effective |
High risk |
Use if Necessary |
|
G If Using Insecticides, Protect Yourself & Minimize Risks
|
A
Maintain A Healthy Lawn
Non-Chemical Method
OSU Turfgrass Management Program
Maintain A Healthy Lawn
Recommended
You can minimize insect damage to your lawn by growing healthy, robust grasses.
| Does it work? | Very effective See Prevent Lawn Problems to learn more. |
| How much effort? | High effort Maintaining a healthy lawn requires planning and ongoing effort. |
| What's the risk? | Low risk |
| Possible risk of exposure or harm from chemicals | NONE |
The best defense against insect problems in your lawn is to maintain a healthy lawn.
B
Monitor for Insects
Non-Chemical Method
“Crane fly scouting (Kowalewski)” by Oregon State University is licensed under CC BY-NC 2.0.
Monitor for Insects
Recommended
If you are concerned about insect damage to your lawn, monitor for insects and their damage.
| Does it work? | Effective Identifying insect pests and determining the scope of damage are the first steps toward getting rid of insects that damage lawns. |
| How much effort? | Low effort Monitoring for lawn insects involves a little work to gain valuable insight about the condition of your lawn. |
| What's the risk? | Low risk |
| Possible risk of exposure or harm from chemicals | NONE |
Perform monitoring activities for lawn insects before you adopt any control actions.
HOW TO DETECT LAWN INSECTS
DRENCH TEST
- Perform a drench test to detect billbugs, chinch bugs, cutworm, and sod webworm larvae.
- Measure out an area of the lawn that’s 3 feet by 3 feet.
- Mix 3–4 tablespoons of dishwashing liquid in 2 gallons of water.
- Evenly apply the 2-gallon solution to the lawn area.
- Watch the area for 10 minutes. Count the number of larvae that come to the surface.
- Consider treating the area only if more than 5 cutworms or 15 lawn moth larvae appear per 3-foot-by-3-foot area.
PEEL BACK GRASS AND INSPECT ROOTS
- Inspect roots to detect billbug and crane fly larvae and white grubs.
- Dig or cut beneath the roots of an area of lawn that measures 1 foot by 1 foot.
- Peel it back and examine the soil around the roots and crowns (where roots and stems meet).
- Look for larvae or grubs.
- If there are many insect larvae in the area, the roots may be damaged.
- If you find more than about 1 billbug larva or 6 white grubs per square foot, control may be needed.
- For crane fly, the threshold for action is 25–50 or more larvae per square foot with noticeable grass thinning.
C
Biological Insecticide Products
Non-Chemical Method
Tomasz Klejdysz, iStock
Biological Insecticide Products
Recommended
- Biological insecticide products such as Bacillus thuringiensis (Bt) and Beauveria bassiana, and beneficial nematodes effectively control lawn insect pests.
- The photo shows an insect larva with many white beneficial nematodes in and around its body.
| Does it work? | Effective
|
| How much effort? | Moderate effort Spot-apply to impacted areas or to the entire lawn based on the label instructions. |
| What's the risk? | Low risk
|
| Possible risk of exposure or harm from chemicals | NONE |
- Biological control products kill grubs and larvae when correctly applied to your yard and landscape.
- They contain living entities or their isolates (byproducts).
- They have minimal impact on natural enemies of insect pests and other beneficial organisms such as earthworms.
- Always read and follow the label instructions when using biological control products.
“Nematodes for pest management” by The NYSIPM Image Gallery is licensed under CC BY-NC 2.0 (cropped).
Louis Tedders, USDA Agricultural Research Service, Bugwood.org
Biological Insecticide Product Options
Beneficial Nematodes
- Insect-attacking nematodes (roundworms) control caterpillars or grubs.
- They are applied as a soil drench (shown in photo above).
- They have minimal negative impacts on pollinators and beneficial insects.
Bacillus thuringiensis (Bt)
- Microbial insecticides derived from Bacillus thuringiensis (Bt) target specific lawn pests.
- For example, Bt israelensis kills crane fly larvae and Bt kurstaki controls cutworm larvae.
- Bt products break down quickly. Repeat application is necessary for effective control.
Beauveria bassiana
- Beauveria bassiana is a naturally occurring soil fungus. It is used as an insecticide.
- The fungus grows on various insects (all stages) and kills or weakens them.
- The photo shows Beauveria growing on insect larvae.
Spinosad
- Spinosad is a biological product made from a naturally occurring bacterium.
- It is effective against lawn caterpillar pests but not grubs or other beetles. Spinosad is considered safe for most beneficial insects as well as for people, pets, and the environment.
- However it is broad-spectrum and can affect bees and some beneficial insects for several days after application.
- Repeated applications each generation are necessary for acceptable control.
D
Neem Oil & Plant Essential Oils
Chemical Method: Use with caution
Weston Miller, Oregon State University
Neem Oil & Plant Essential Oils
Use if Necessary
- Insecticides with neem oil (shown in photo) and plant essential oil as active ingredients effectively kill many lawn insect pests. They have lower beneficial impact than other chemical methods.
- Plant essential oils include clove, mint, rosemary, and other aromatic (strong smell) ingredients derived from plants.
| Does it work? | Effective
|
| How much effort? | Moderate effort Spot-apply to impacted areas or to the entire lawn based on the label instructions. |
| What's the risk? | Moderate risk Insecticides come with real risks. ALWAYS read the entire label front to back. Use a magnifying glass. |
| Possible risk of exposure or harm from chemicals | El uso de insecticidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos. You may be exposed to an insecticide if you:
Follow directions closely to reduce risk. |
Neem oil and plant essential oils are good choices to kill lawn insect pests in many situations.
E
Broad-Spectrum Insecticides
Chemical Method: Use with caution
Weston Miller, Oregon State University
Broad-Spectrum Insecticides
Use if Necessary
- Active ingredients in this group of insecticide products include active ingredients in the pyrethroid group (many different names) and carbaryl.
- Products work, but can kill many beneficial insects. They may get into waterways and harm aquatic life. Their use can be avoided by using other methods before insect pests damage turf.
| Does it work? | Effective
|
| How much effort? | Moderate effort Spot-apply to impacted areas or to the entire lawn based on the label instructions. |
| What's the risk? | High risk
|
| Possible risk of exposure or harm from chemicals | El uso de insecticidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos. You may be exposed to an insecticide if you:
Follow directions closely to reduce risk. |
If you determine you need an broad-spectrum insecticide product to treat lawn insects(s), choose products that mention use for lawn areas.
Weston Miller, Oregon State University
More about Broad-Spectrum Insecticide Products
- Broad-spectrum insecticides are broadly toxic to insects. They kill grubs, lawn moths, and cutworms. However, they also kill beneficial insects and can harm aquatic life.
- Proper timing of insecticide treatments is critical for them to be effective.
- Confirm the identity of the damaging insects in your lawn. Follow the label instructions for that kind of insect for best results.
- Some insecticides are highly toxic to bees. Do not spray directly onto blooming crops or weeds. Do not allow drift onto blooming crops or weeds where bees are foraging.
Broad-spectrum insecticides are highly toxic to all arthropods, including natural enemies and pollinators. Killing natural enemies may lead to outbreaks of spider mites or other pests. Insecticides may wash off plants and run into storm drains and waterways. These broad-spectrum insecticides adversely affect non-target aquatic organisms.
F
Systemic Insecticides for Lawns
Chemical Method: Use with caution
Weston Miller, Oregon State University
Systemic Insecticides for Lawns
Use if Necessary
- Systemic insecticides in the neonicotinoid group include active ingredients such as imidacloprid and clothianidin.
- Products work, but can kill many beneficial insects. Their use can be avoided by using other methods before insect pests damage turf.
| Does it work? | Effective
|
| How much effort? | Moderate effort Spot-apply to impacted areas or to the entire lawn based on the label instructions. |
| What's the risk? | High risk
|
| Possible risk of exposure or harm from chemicals | El uso de insecticidas conlleva cierto grado de riesgo. El riesgo más bajo se presenta con el uso de métodos alternativos. You may be exposed to an insecticide if you:
Follow directions closely to reduce risk. |
If you determine you need a systemic insecticide product to treat lawn insects(s), choose products that mention use for lawn areas. Follow the label instructions for best results and to minimize risks.
More About Systemic Insecticide Products
- Systemic insecticide products are applied as a soil drench in spring. Adequate rain or irrigation is required to move the product through the soil to the roots.
- A single application may provide season-long control when applied according to the label directions.
Neonicotinoid insecticides can harm pollinators and natural enemies. Following application, the poison may be found in flowers for months or years. Beneficial insects feed on the nectar and pollen. For more information, see OSU’s How to Reduce Bee Poisoning from Pesticides
If Using Insecticides, Protect Yourself & Minimize Risks
Chemical Method: Use with Caution
Fly View Productions, iStock
Why is It Important to Read Insecticide Labels?
- They have detailed information on how to use the product correctly and legally.
- They contain information on potential hazards of the product.
- They provide instructions you should follow for poisonings and spills.
- Following label instructions helps you to minimize the risks and maximize the benefits.
Key Insecticide Safety Tips
- Read the entire label front to back.
- Follow the instructions.
- Review the instructions even for brands you know.
- Only apply the product where the label says it may be applied.
- Be precise in your application. More is not better.
The Label is the Law
ALWAYS read the label before using insecticide products. The label is a legal document that provides information on how to safely use the insecticide. This helps avoid harm to human health and the environment. Using an insecticide in off-label ways is illegal. It can result in legal enforcement actions.
READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.
- Labels are different for every product and they often change over time.
- Use a magnifying glass for small print.
- Pay attention to CAUTION, WARNING, and DANGER statements.
- Pay attention to the PRECAUTIONARY STATEMENTS.
- The law states you must read and follow insecticide instructions.
Protect Yourself
Eye, skin, & lung irritants
- Wear gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
- Avoid contact with eyes, skin, or clothing.
- Wash hands after mixing or applying, and before eating or smoking.
- Never spray directly overhead. Pay attention to wind conditions.
Protect Children & Pets
Keep out of the reach of children.
- Keep children and pets away from the application area.
- Remove toys and pet dishes from the area before applying insecticides. Wait until spray has dried or dust has settled.
Avoid Wet Weather & Keep Insecticides Out of Waterways
Some insecticides are toxic to fish and aquatic invertebrates.
- Don’t spray insecticides in water.
- Insecticides sprayed on plants can wash off with rain and enter waterways.
Storage & Disposal
- Store out of the reach of children and pets.
- Store in a cool and dry place.
- Never pour down any drain.
- If you mix too much, apply it rather than storing it.
- Don’t put pesticide containers in the trash unless instructed by the label.
- Take unused insecticides to a hazardous waste facility.
Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.
For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website
More about:
About Using Pesticides on School Grounds in Oregon
If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).
NEED HELP?
The National Pesticide Information Center (NPIC) can answer questions about pest control chemicals.
1-800-858-7378 or npic@ace.orst.edu
Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.
Content provided by editor Weston Miller and writer Signe Danler. Pesticide safety information edited by Kaci Buhl.
Reviewed by OSU Department of Horticulture.
LAWN INSECT REFERENCES
Turfgrass Pests
PNW Pest Management Handbooks
Lawn Insects
University of California IPM
Managing Crane Fly in Lawns
Oregon State University Extension