The garden chafer (Phyllopertha horticola) is one of the most common pest beetles in the UK, notorious for the damage its larvae cause to lawns and gardens. Found across various regions in the UK, the garden chafer has a one-year lifecycle, with adult beetles emerging in late spring or early summer. Understanding how to identify, avoid, and control this pest is essential for maintaining healthy turf and ornamental plants.
Identification
The garden chafer is relatively easy to identify compared to other chafer species in the UK. Adult garden chafers are small, measuring around 10mm in length, with distinct chestnut-brown wing cases and a metallic green head and thorax. They also have fan-like antennae, characteristic of chafer beetles. These beetles are most active during May and June, when they can often be seen flying just above the surface of lawns on warm, sunny days.
The larvae, or grubs, are cream-colored with brown heads and are typically found in a C-shaped position just beneath the soil. These larvae feed on the roots of grass and other plants, causing significant damage to lawns and gardens. Garden chafer larvae are smaller than those of other chafer species, measuring up to 15mm at full size.
Chafer Species in the UK
In addition to the garden chafer, there are several other species of chafer beetles found in the UK, each with its own lifecycle and characteristics. The four main species are:
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Garden Chafer (Phyllopertha horticola): The most common species, with a one-year lifecycle. Adults emerge in May or June and lay eggs in the soil, where the larvae develop over the summer.
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Summer Chafer (Amphimallon solstitiale): Similar in appearance to the cockchafer but smaller, measuring 15-20mm. The summer chafer has a two-year lifecycle, with adults emerging between June and August.
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Cockchafer (Melolontha hippocastina): Known as the May bug, this is the largest chafer species in the UK, reaching up to 30mm in length. The cockchafer has a three-year lifecycle, with larvae feeding deep in the soil and causing extensive damage.
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Welsh Chafer (Hoplia philanthus): Found primarily in the soil of grasslands and lawns, the Welsh chafer has a four to five-year lifecycle. This species is less common but can still be a serious pest, especially in turf.
How to Avoid the Garden Chafer
Preventing garden chafer infestations involves taking several proactive measures, particularly during the beetles' active periods in late spring and early summer. Keeping your lawn healthy and well-maintained is a key strategy for avoiding an infestation. Regular aeration, scarifying, and reducing the amount of thatch in the lawn can help disrupt the environment where the garden chafer lays its eggs.
One of the most effective ways to prevent adult garden chafers from laying eggs is to use pheromone traps. These traps attract adult beetles, reducing their ability to mate and lay eggs. Installing pheromone traps in early May, before the beetles start flying, can help reduce the number of larvae that develop later in the season.
Maintaining a thick, well-fertilized lawn can also deter the garden chafer from laying eggs. Lawns that are dense and healthy are less likely to be targeted by the beetles, as they prefer softer, less compacted soil for laying eggs.
Where the Garden Chafer is Found
The garden chafer is widespread across the UK, particularly in temperate regions with well-maintained lawns and gardens. It thrives in gardens, parks, golf courses, and other grassy areas. The larvae live just below the surface of the soil, feeding on grass roots and causing yellow patches in the turf. As the larvae destroy the root system, large areas of the lawn may die off, leading to unsightly damage that can be difficult to repair.
Regions across the UK, especially in areas with moist, rich soil, are prone to garden chafer infestations. These beetles can be found in both rural and suburban areas, though they are most commonly associated with well-maintained lawns and recreational spaces.
Life Cycle of the Garden Chafer
The garden chafer’s lifecycle begins when adult beetles emerge from the soil in late May or early June. The adults mate soon after emerging, with females laying eggs in the soil at a depth of around 10cm. Each female can lay up to 50 eggs in her lifetime, typically in clusters of two to six eggs at a time. These eggs hatch within a few weeks, and the larvae begin feeding on grass roots immediately.
The larvae go through three instar stages before reaching full size in the autumn. At this stage, they burrow deeper into the soil to overwinter, emerging again in the following spring to pupate. The pupae develop into adult beetles in late spring, completing the lifecycle.
How to Control the Garden Chafer
Controlling garden chafer infestations requires a combination of physical, biological, and, in some cases, chemical methods. One of the first steps is to inspect your lawn for signs of damage, such as yellow patches or areas of dead turf. If you suspect an infestation, you can lift the turf to check for the presence of larvae.
Biological Control
A popular and environmentally friendly method for controlling garden chafer larvae is the use of entomopathogenic nematodes, particularly the species Heterorhabditis bacteriophora. These microscopic worms are natural predators of the larvae and can be applied to the soil when conditions are moist and warm, typically between 12°C and 20°C. Once in the soil, the nematodes infect the larvae with bacteria that kill them within a few days. This method is particularly effective in targeting larvae before they cause extensive damage.
Cultural Practices
Maintaining a healthy lawn is one of the best defenses against garden chafer infestations. Regular aeration and scarifying help improve soil drainage and reduce compaction, making it harder for female beetles to lay their eggs. Keeping the lawn well-watered and fertilized also promotes strong root growth, which can help turf recover from damage caused by larvae.
In some cases, the larvae may be exposed to predators, such as birds and mammals, when the soil is disturbed through aeration or cultivation. While this can lead to additional damage as animals dig for the larvae, it can also help reduce the population of chafer grubs.
Chemical Control
For severe infestations, chemical insecticides may be required. In the UK, Acelepryn has been granted emergency authorization for the control of chafer grubs. However, it is important to note that chemical treatments should be used as a last resort, as they can have negative effects on non-target species and the environment. Always follow the manufacturer's instructions carefully and consider combining chemical treatments with biological and cultural methods for a more sustainable approach to pest control.
Regional Occurrence in the UK
The garden chafer is most commonly found in temperate regions of the UK, particularly in areas with moist, fertile soil. It is widespread across much of England, Wales, and parts of Scotland, thriving in gardens, parks, and other areas with well-maintained lawns. While the garden chafer is less common in some northern and high-altitude regions, it can still be found in isolated pockets where conditions are suitable.
In conclusion, controlling garden chafer infestations requires a combination of preventative measures and active management. By identifying the pest early and using a combination of biological, cultural, and chemical controls, homeowners and gardeners can effectively reduce the damage caused by garden chafer larvae and maintain healthy, vibrant lawns throughout the year.