**Scarabs** (Family Scarabaeidae) are a diverse family of beetles that includes many familiar types, such as **Dung Beetles** (beneficial), **June Bugs** (*Phyllophaga* species, pests), and **Japanese Beetles** (*Popillia japonica*, pests). The conflict varies from beneficial to severe: the larvae (known as **White Grubs**) are major pests of turfgrass and crop roots, while the adults of some species (like Japanese Beetle) are severe pests of foliage and flowers, and others (like Dung Beetles) are vital **ecosystem recyclers**.
Taxonomy and Classification
Scarabs belong to the order Coleoptera (Beetles). They undergo complete metamorphosis. The key conflict stage is the larva (grub), which is typically white, C-shaped, and found feeding in the soil on roots or decaying organic matter.
Physical Description
Adult Scarabs vary widely, from 1/4 inch up to several inches long.
- **Larva (Grub – Key ID):** White or grayish, fleshy, C-shaped body with a brown head capsule and six thoracic legs, found underground.
- **Adult (Key ID):** Robust, often heavy-bodied beetles. Many are shiny, metallic (Japanese Beetle), or dull brown (June Bug).
- **Damage Sign (Key ID):**
- **Grub Damage:** Irregular brown patches in lawns that can be rolled back like a rug (roots severed); heavy presence of feeding animals (skunks, birds) digging for grubs.
- **Adult Damage:** Skeletonized leaves, large holes chewed in flowers and fruit.
- **Conflict:** Root feeding, foliage consumption, and soil recycling (beneficial).
Distribution and Habitat
Scarabs are cosmopolitan. Their habitat is diverse, including forests, agricultural fields, grasslands, and especially turfgrass. Larvae live in the soil; adults live on foliage, flowers, or manure/carrion.
Behavior and Conflict
The conflict is highly dependent on the species.
- **Grub Damage:** High populations of root-feeding grubs cause the grass roots to be severed from the soil, leading to rapid turf death.
- **Dung Beetle Benefit:** Dung Beetles are highly beneficial, recycling manure and removing larval fly habitats from livestock operations.
- **Invasiveness:** Invasive species like the Japanese Beetle (*Popillia japonica*) have wide host ranges and cause severe damage to high-value ornamental plants.
Management and Prevention
Control is integrated pest management (IPM), with precise timing for grub control.
- **Monitoring:** Sample the soil to determine grub species and population density.
- **Timing:** Apply insecticides or biological controls (entomopathogenic nematodes) in the late summer or early fall when the grubs are small and feeding near the soil surface.
- **Hand Removal:** Hand-pick adult Japanese Beetles from high-value plants.
- **Traps:** Adult pheromone traps are only recommended when placed far away from the protected plant, as they can attract more beetles than they capture.
Conservation and Research
Scarabs are managed as both major pests (grubs) and crucial beneficials (dung beetles). Research focuses on developing grub-specific biological controls (nematodes, milky spore) and methods to enhance dung beetle populations for sanitation and soil health.