Anomala splendens

Anomala splendens is a member of the Scarabaeidae family, within the order Coleoptera. These beetles are easily identified by their distinct, brilliant metallic luster, which serves as their primary diagnostic trait in the field.

The adult beetle has a moderately convex, oval-shaped body. The coloration ranges from vivid metallic green to bronze or copper, providing effective camouflage against green foliage during their feeding periods.

The larvae are typically C-shaped, common for scarabs, and are white in color. They feature a robust, chitinous head with strong mandibles designed for feeding on organic matter and plant roots.

Adult beetles are highly active, especially during sunny daytime hours. They are strong fliers and can travel significant distances to locate suitable host plants for feeding and oviposition.

The life cycle undergoes complete metamorphosis, consisting of four stages: egg, larva, pupa, and adult. The total duration of the cycle is heavily influenced by regional climate and soil moisture levels.

Both adults and larvae cause damage, though the nature of the destruction varies significantly between stages. Adults feed on leaves, consuming the lamina and leaving behind only the tougher leaf veins.

The larvae, often referred to as white grubs, reside in the soil and feed on the root systems of various crops. This feeding behavior disrupts water and nutrient uptake, leading to plant decline.

Seedlings and young plants are particularly susceptible. Severe infestations can result in the complete destruction of the root ball, causing young trees or shrubs to wither and die rapidly.

Anomala splendens targets a wide variety of plants, including orchards, vineyards, and decorative nursery stock, making it a significant economic pest in agricultural regions.

• Fruit trees (apple, pear)
• Grapevines
• Berry bushes (raspberry, currant)
• Ornamental garden plants

Adults emerge from the soil in late spring or early summer, following the first sustained periods of warm weather. Peak activity is generally observed during the months of June and July.

During the flight season, adult beetles feed and mate. Females search for moist, loose soil containing organic material to deposit their eggs, ensuring optimal conditions for larval survival.

The larval stage is characterized by intense feeding throughout the summer and autumn. As temperatures drop in late autumn, larvae migrate deeper into the soil profile to overwinter.

In the following spring, as soil temperatures rise, larvae move upward and enter the pupal stage. The pupal phase lasts several weeks until the new generation of adults emerges.

Environmental factors, such as extreme drought or prolonged rainfall, can alter these timelines by either accelerating or delaying the development of the population.

A classic sign of infestation is skeletonized foliage. When adults feed on leaves, they consume the soft tissue between veins, resulting in a lace-like appearance of the tree canopy.

Plants showing sudden wilting symptoms, despite regular irrigation, indicate potential larval damage to the root system. This is especially prevalent in container-grown plants or young nursery trees.

Inspection of the soil around the base of affected plants often reveals C-shaped white grubs. Finding a high concentration of these larvae confirms the need for immediate intervention.

The presence of brilliant, metallic beetles on leaves during sunny hours is a clear visual indicator of their presence and active feeding on the property.

Increased activity of birds, such as starlings or rooks, foraging in the soil is a frequent secondary sign that a population of grubs exists beneath the turf or around the plants.

Soil-applied insecticides are effective in managing larval populations. These should be applied and watered into the root zone to ensure contact with the feeding grubs.

For adult beetle control, foliar sprays with systemic or contact insecticides are recommended during the peak emergence window to prevent leaf damage and reduce egg-laying opportunities.

Mechanical control, such as cultivating the soil, can help expose larvae to predators and desiccation by the sun, significantly reducing the pest population in small garden plots.

Biological control options, including the use of entomopathogenic nematodes or fungi like Beauveria bassiana, provide an environmentally friendly alternative to chemical pesticides.

Good agricultural practices, such as proper weed control and avoiding the use of uncomposted manure, help make the site less attractive to egg-laying female beetles.