Billbugs: How to Identify and Control It in Your Lawn


Is your once lush and green lawn looking a bit lackluster? Are you noticing thinning turf, brown patches, or even sections of dead grass? If so, your lawn may be infested with billbugs. These pesky weevils can wreak havoc on your turf and turn your beautiful lawn into a barren wasteland. In this comprehensive guide, we will explore the different types of billbugs, their life cycle, and, most importantly, how to identify and control them to restore your lawn to its former glory.

Understanding Billbugs

Billbugs are a type of weevil belonging to the genus Sphenophorus. There are 71 different species of billbugs worldwide, with 64 of them found in North America. These pests have a particular affinity for high-cut turfgrass and can be present at any time of the year. While there are various species of billbugs, the most common ones include bluegrass billbugs, hunting billbugs, lesser billbugs, unequal billbugs, phoenix billbugs, rocky mountain billbugs, and corn billbugs.

Bluegrass Billbugs

The bluegrass billbug (Sphenophorus parvulus Gyllenhal) is considered the most harmful type for cool-season turf. This species is prevalent in the Northeastern states, such as Maine, New Jersey, and New York. Bluegrass billbugs primarily target Kentucky bluegrass, perennial ryegrass, fescues, and bentgrass. However, they can also infest warm-season turf found in Southeastern states like Florida, North Carolina, and Texas.

Hunting Billbugs

Hunting billbugs (S. venatus vestitus Chittenden) are another common and destructive variety of billbugs. Like bluegrass billbugs, these weevils threaten cool-season grasses and are often found in New Jersey and Virginia. In the South and along the Gulf Coast, they target warm-season grasses such as Zoysiagrass, Augustine grass, Bermudagrass, Bahia grass, and St. centipede grass.

While other types of billbugs are not as prevalent, they can still be found from coast to coast and even in Hawaii. Adult billbugs are characterized by their black or gray color, long, narrow snout, and broad thorax. The larvae, on the other hand, are cream or white and resemble small white grubs.

Billbug Damage: What to Look For

Billbugs can cause significant damage to your lawn, but the signs may not be immediately apparent. The first signs of billbug damage typically become noticeable as temperatures begin to warm. Billbugs overwinter as adults and lay their eggs in grass stems during late spring and early summer. The eggs hatch into larvae about one to two weeks later, and it is during this larval stage that billbugs cause the most harm to your turf.

As the larvae burrow down below the grass blades and towards the crown and roots of the turf, they feed on the grass. However, the damage may not become apparent until mid to late July or August when the larvae pupate. During months with little rainfall, if the billbug larvae destroy the turf crowns, it can lead to the death of the entire grass plant. Initially, the damage may appear as thinning or irregular mottling of the grass, resembling the effects of a lack of water. If left untreated, the entire lawn can eventually turn brown and die.

According to Dr. David Smitley at Michigan State University Extension, the threshold for billbugs is “unacceptable damage or 1/3 of grass plants dead.” Identifying a billbug infestation early on is crucial to prevent extensive damage to your lawn.

How to Identify a Billbug Infestation

If you suspect a billbug infestation in your lawn, it’s essential to correctly identify the culprit. Proper identification will determine the most effective treatment strategy. One way to identify billbug larvae is by examining the damaged turf. Here’s a step-by-step process to help you determine if you have a billbug infestation:

  1. Tug at the dead stems of the turf: If the stems break easily, it could be a sign of billbug damage.
  2. Inspect the stems: Look inside the stems to see if they are hollowed out and filled with sawdust-like frass material. This material is the excrement of the billbug larvae.
  3. Examine the grass stems: If the grass stems contain sawdust-like material, it is a clear indication of a billbug infestation.

If you observe these signs, your lawn is likely infested with billbugs. However, suppose you are unsure or have trouble identifying the pests. In that case, it is always a good idea to seek assistance from your local county extension agent or a professional lawn care service.

Preventative Measures to Control Billbugs

The best approach to dealing with billbugs is prevention. By implementing proper lawn care practices, you can reduce the risk of a billbug infestation and keep your lawn healthy and resilient. Here are some proactive steps you can consider:

1. Select Well-Adapted Turfgrass

Choosing turfgrass varieties that are well-adapted to your specific region and climate is crucial. Selecting the right grass will ensure its natural resistance to pests, including billbugs. Consult with a local lawn expert or refer to your local extension office for guidance on the best turfgrass options for your area.

2. Maintain Proper Mowing, Fertilization, and Irrigation

Regularly mowing your lawn at the appropriate height and frequency promotes healthy turf growth and helps prevent billbug infestations. It is essential to follow recommended mowing practices for your specific grass type. Additionally, proper fertilization and irrigation are essential for maintaining a robust and resilient lawn.

3. Manage Thatch

Thatch buildup can create an ideal environment for billbugs to thrive. Regular dethatching, especially in areas prone to thatch accumulation, can help prevent billbug infestations. Thatch removal promotes better air circulation and reduces the moisture levels that billbugs find attractive.

4. Practice Turf Cultivation

Regularly aerating your lawn and overseeding with resistant grass varieties can help prevent billbugs. Turf cultivation helps improve soil compaction, encourages deeper root growth, and enhances the overall health of the turf. Strong and healthy grass is less susceptible to billbug damage.

5. Opt for Endophyte-Enhanced Turfgrasses

Endophytes are beneficial fungi that live symbiotically within certain grass species. Endophyte-enhanced (E+) turfgrasses, such as perennial ryegrass, creeping red fescue, and tall fescue, have shown resistance to both billbug larvae and adults. Sodding your lawn with E+ cultivars can significantly reduce the risk of a billbug infestation.

Implementing these preventative measures will bolster your lawn’s defenses against billbugs and minimize the need for more aggressive control methods.

Controlling Billbugs with Insecticides

If preventative measures fail and your lawn is already infested with billbugs, you may need to resort to insecticide treatments to regain control. Integrated pest management (IPM) is a strategic approach that combines various pest control methods to minimize the use of chemical insecticides. However, if the infestation is severe, targeted insecticide applications may be necessary.

Insecticides for Billbug Control

Several insecticides have proven effective in controlling billbugs. When using insecticides, it is crucial to follow label instructions and safety precautions. Here are some commonly recommended insecticides for billbug control:

  • Aloft
  • Arena
  • Meridian
  • Merit

According to Dr. David Smitley at Michigan State University Extension, these insecticides should be applied in mid to late May on lawns that have previously experienced billbug damage. Proper timing is crucial to target adult billbugs and prevent them from laying eggs.

Pest Control Methods for Billbugs

The specific pest control methods for billbugs may vary depending on your location and the recommendations of local experts. Generally, there are three primary strategies for managing billbugs: preventive adult billbug control, preventive billbug larvae control, and curative billbug larvae control.

Preventive Adult Billbug Control

Preventive adult billbug control involves applying insecticides on the surfaces of your lawn to target billbug adults before they begin laying eggs. This method is most effective when timed correctly. The timing can vary depending on your region, so it is essential to research or consult with local experts for optimal timing in your area. In certain cases, biological controls such as insect-parasitic nematodes can also be used as an alternative to chemical insecticides.

Preventive Billbug Larvae Control

Preventive billbug larvae control targets the eggs after adult billbugs have laid them. Neonicotinoids or diamides are commonly used insecticides for this purpose. The plants absorb these chemicals and distribute them throughout their tissue, effectively reaching and destroying the billbug larvae. Timing is crucial for this method, and it is generally recommended to coincide with the timing of adult control applications.

Curative Billbug Larvae Control

Curative billbug larvae control is employed when damage has already occurred. The primary goal is to prevent further damage and restore the health of the affected lawn. Most insecticides approved for use on turfgrass can be applied for curative control, including neonicotinoids, organophosphates, and carbamates. To ensure effective control, it is important to water the treated area within 24 hours of application to reach the larvae living in the soil.

Seeking Professional Assistance

Managing billbug infestations can be challenging, especially for homeowners without experience in pest control. In such cases, it is advisable to seek help from lawn care service providers or pest control companies specializing in billbug management. These professionals have the expertise and resources to accurately identify billbug infestations and employ the most effective treatment strategies.

Additionally, many local extension offices offer free lawn analyses, providing homeowners with valuable insights and recommendations to address billbug problems. Don’t hesitate to reach out to your local extension office for assistance.


Billbugs can wreak havoc on your lawn, turning it from a vibrant green oasis to a withered and brown patch of land. By understanding the different types of billbugs, their life cycle, and the signs of infestation, you can take proactive measures to prevent and control these lawn pests. Implementing proper lawn care practices, such as selecting well-adapted turfgrass, regular mowing and maintenance, managing thatch, and practicing turf cultivation, will go a long way in deterring billbugs.

If preventive measures fail, insecticide treatments can help regain control. Integrated pest management (IPM) techniques, including endophyte-enhanced turfgrasses, can also effectively prevent billbug infestations. When using insecticides, always follow label instructions and consider seeking professional assistance if needed. With proper identification, timely intervention, and a proactive approach to lawn care, you can successfully identify and control billbugs, ensuring a healthy and vibrant lawn for years to come. Remember, a well-maintained lawn is the best defense against these pesky pests.

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