Have you ever been in your garden and found a large, white, C-shaped larva with a characteristic brown head and six legs clustered near the head?
If so, have you encountered scarab larvae (family: Scarabidae) Also known as a “curl grab”.
Many gardeners worry that these large larvae will damage their plants.
What is a curl grab? And should I be concerned if I find them in my garden?
What is a curl grab?
Carl Grab turns into a chafer.
There are over 30,000 species of scarab beetles worldwide. Australia is home to at least 2,300 of these species, including the rainbow Christmas beetle (Anoprognathus), a beetle with magnificent horns (dynasty), beautifully patterned flower chafer (Ketoninae).
Adults may be the most prominent life stage, but chafers spend most of their lives as larvae, living underground or in rotting wood.
Chafer larvae can help the environment
Soil-dwelling chafer larvae help aerate the soil and disperse the seeds.
Decay-eating seeds recycle nutrients and help keep the soil healthy.
Most chafer larvae are large and full of protein and fat. They make a great meal for hungry birds.
Besides being important to the ecosystem, scarabs also play a role in cultural celebrations.
For example, the ancient Egyptians famously worshiped the sun through the symbol of a ball-rolling dung beetle.
Colorful Christmas beetles have traditionally ushered in the holiday season in Australia.
Sadly, Christmas beetle numbers have declined over the past few decades, probably due to habitat loss.
Are curly larvae in my garden harming my plants?
Most chafer larvae feed on grass roots, but high grass roots can damage plants.
In Australia, the Argentine lawn chafer and the African black beetle are invasive pest species that cause significant damage to pastures and lawns.
Native chafers can also become pests under the right circumstances.
For example, when Europeans began planting sugarcane (a type of grass) and converting native grasslands to pastures, many native Australian scarab species found a rich new food source and were subsequently classified as pests. I got
Unfortunately, little is known about the feeding habits of many native chafer larvae, including those found in gardens.
Beautifully patterned fiddler crab (Eupoecila australasiae), feed on rotten wood, and are unlikely to harm garden plants.
Even root-consuming species may not be a problem under normal conditions.
Plants are remarkably resilient, and most can cope with the gradual loss of roots to beetle larvae. Even while damaging plants, curl grub may be helping keep the soil healthy by providing aeration and a nutrient mix.
Read more: Testing the stress levels of rescued koalas helps you tune your koala care and help more survive in the wild.
How can I tell if I have “good” or “bad” beetle larvae in my garden?
Unfortunately, it is difficult to identify the species of chafer larvae. Many of the features we use to distinguish between groups are difficult to see without zooming in. Although there are identification guides for chafer larvae found in meadows, there are currently no identification resources for scarab beetles found in home gardens.
The best guide to determining if scarab beetle larvae are a problem in your garden is the health of your plants, as they can be impossible to identify. Plants with damaged roots may wilt or turn yellow.
Most root-eating chafers prefer grass roots, so lawns are most at risk, and damage is usually caused by invasive chafers.
What should I do if I find caterpillars in my garden?
It may surprise you to see suspiciously plump curly larvae inside the roots of your prized garden plant, but don’t automatically reach for pesticides.
The chemicals used to control curl grabs harm all chafer larvae, whether they are pests or not.
Many of the most common treatments for curl larvae contain chemicals called “antranyldiamides,” which are also toxic to butterflies, moths, and aquatic invertebrates.
In addition, the use of pesticides can be harmful by disrupting the soil ecosystem, killing harmless native beetle larvae.
Read more: Why is my house infested with pantry moths and how can I get rid of them? Experts explain
what should i do instead?
The larvae found in decaying wood and mulch are wood feeders and useful composters. They do not harm your plants and should be left alone.
Larvae found in compost bins help break down waste and should be left alone.
If you find larvae in your garden soil, take your plant’s health as a guide. If the plant looks healthy, consider leaving the curled larvae alone. Scarab beetle larvae are part of the soil ecosystem and are unlikely to cause harm unless they are present in large numbers.
If your plants turn yellow or wilt, and you can’t think of other causes such as under-watering or nutrient deficiencies, consider feeding or crushing the larvae to birds. Not better, but better than insecticide.
Lawns are particularly susceptible to attack by invasive chafer larvae. Consider replacing the lawn with a native ground cover. This improves biodiversity and reduces the potential for damage from invasive chafer larvae.
Chafers are beautiful and attractive insects that keep soil healthy and provide good nutrition for wildlife.