Scarab Beetles
Scarabaeidae
Scarab Beetles, Scarabs, Chafer Beetles, Dung Beetles, White Grubs
Polyphylla decemlineata aka Ten-lined June beetle 2015-05-21 by Junkyardsparkle (CC0)
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Polyphylla decemlineata aka Ten-lined June beetle 2015-05-21 by Junkyardsparkle (CC0)
1 of 7
The Scarab Beetle family holds over 30,000 species! Its an incredibly diverse group, possessing just under 20 subfamilies.
Most species are nocturnal, but groups such as the flower chafers and leaf chafers can be found active during the daytime.
Some can be root pests as larvae, chewing on flower petals as adults. However, they can also be highly beneficial, because as larvae, they break down bits of organic matter in the soil media, assisting with soil formation.
Dung Beetles even more so. Some feed primarily on dung, whereas others live in it. In doing so, they assist the natural process of soil decomposition and increase the rate of soil formation.
Traits

Can sometimes feed on the plants rooting system, which can cause grass to turn brown.

Helps break down organic matter in the soil, improving soil fertility.
Appearance
Adults: Scarabs are stout and chunky beetles. Many are coloured with metallic iridescent colours, displaying an array of colours when the light reflects from them. Many species possess thick, flattened legs which are modified for digging. The antennae are also flattened, getting thicker towards the ends. They are stalked, looking similar to a fan. The males use these to detect female pheromone trails. The largest beetle can grow as large as 16cm!
Larvae: The grubs are characteristically C shaped, usually pale yellow-whitish with an orange-brown head. They can sometimes take years to reach maturity.
Activity
Diurnal
Personality
Order
Coleoptera
Family
Scarabaeidae
Metamorphosis
Complete
Distribution
Worldwide
Biological treatment
Turn over the soil, remove them by hand and feed them to the birds. They love them!
Try neem oil! Be sure to read instructions before applications.
Water well, they don't like abundant water, and it will also be useful for damaged roots as it will be easier to absorb the water.
Please note that coming across one or two grubs in your garden bed is usually no cause for alarm. Larger numbers with significant damage is a different story. Potted plants, on the other end, should always be controlled.
Chemical treatment
Chemical control is rarely necessary. White grubs are a food source to many other types of wildlife.
Repels
Parasitic wasps, flies, moles, birds and other wildlife.