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Learn about plant insect control for commercial premises.
If you’ve noticed large, buzzing beetles flying around lights on warm spring evenings, you might be seeing cockchafers. These insects, often called may bugs or doodlebugs, are a common pest across parts of the United States. While they may look intimidating, they are harmless to people but can cause significant damage to plants and lawns during their larval stage.
What are cockchafers?
The cockchafer (Melolontha melolontha) is a large beetle known for its distinctive coloring. As part of the scarab beetle family, they play a role in the natural environment but can become problematic when populations grow. Their larvae, often called white grubs, feed on plant roots and can severely affect crops, turf, and garden plants.
Key characteristics
The traits below describe how to recognize both adult cockchafers and their larvae in and around your garden.
- Adult cockchafers are large and heavy-bodied, usually between one and one-and-a-half inches long.
- They are reddish-brown with fan-shaped antennae that help them sense their surroundings.
- The abdomen curves downward and ends in a point, which can look like a stinger but is harmless.
- Larvae are white, C-shaped, and found in soil where they feed on plant roots.
The cockchafer life cycle is long, typically lasting about four years from egg to adult. Females lay eggs in soil during late spring, which hatch into grubs that feed on roots for several years before pupating. Adults emerge in May, giving rise to their nickname, the may bug.
Adults live only a few weeks, during which they mate and lay eggs for the next generation. This extended life cycle means damage from larvae can continue year after year if not addressed. Understanding their development helps in managing their populations more effectively.
Cockchafer habitats include forests, grasslands, gardens, and farmlands where the soil is loose enough for burrowing. This can make them a formidable agricultural pest. They are especially active in regions with moderate climates and rich, well-drained soil. Adults are attracted to light sources at night, often gathering near buildings or outdoor lights in spring.
The cockchafer diet depends on life stage. Larvae feed primarily on the roots of grasses and other plants, which can cause patches of dead turf or weakened crops. Adult beetles feed on the leaves of trees and shrubs, and while light feeding causes minimal harm, large populations can defoliate plants quickly.
Cockchafers can be found throughout most of the United States, particularly in the Midwest, Northeast, and parts of the Pacific Northwest, where the soil is rich and suitable for burrowing. They prefer temperate regions with grassy areas, fields, and wooded edges that support their larvae. Adults are often seen in spring around outdoor lights or vegetation near homes and farms.
Managing cockchafers
Managing cockchafers requires understanding both their active adult phase and their long underground larval stage. The sections below explain how to prevent infestations and control existing populations around your property.
Preventing cockchafer infestations
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Keep lawns healthy through regular maintenance and aeration to discourage egg laying.
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Avoid overwatering, which can attract females seeking moist soil for eggs.
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Turn the soil in spring and fall to expose larvae to predators such as birds.
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Remove outdoor lighting when possible during peak flight periods to reduce attraction.
These preventive measures can help reduce the likelihood of a cockchafer infestation or infestations from other pests, and minimize root damage in your yard or garden.
Effective cockchafer control methods
Small infestations can sometimes be reduced by encouraging natural predators like birds and beneficial nematodes - roundworms - that feed on larvae. This may inhibit other issues, though, and DIY methods rarely solve the issue at the root level.
Our technicians can assess the situation, identify affected areas, and provide targeted, customized treatments to reduce populations. Professional support helps protect your plants and turf from long-term damage while addressing the underlying cause of the infestation.
Frequently asked questions
They are about one to one-and-a-half inches long, reddish-brown, and have distinctive fan-shaped antennae. Their heavy bodies and loud buzzing flight make them easy to spot. The larvae are white and C-shaped, found in soil.
They are most active in late spring and early summer, particularly during May, which is why they’re sometimes called may bugs. Adults are often seen flying around lights at dusk.
No, cockchafers do not bite or sting. They may look intimidating due to their size and flight behavior, but they are completely harmless to people and pets. Their impact is mainly limited to plants and crops.
Adult cockchafers feed on tree and shrub leaves, while their larvae consume the roots of grasses and other plants. Heavy larval feeding can damage turf and crops by weakening the plants. In most cases, the damage is gradual but can build up over several years.