Keel-backed scarab

The keel-backed scarab (Trochalus carinatus) is a beetle belonging to the order Coleoptera and the family Scarabaeidae. This insect is recognized as a significant agricultural pest in various regions. Its morphological characteristics allow it to survive in diverse soil conditions, making it a persistent threat to both field crops and horticultural plantations if not properly managed.

This pest primarily attacks the root systems of various plants, including cereal crops, vegetables, and fruit trees. While larvae are the most destructive stage due to their direct consumption of roots, adult beetles also cause damage by feeding on foliage, buds, and young shoots. This dual-stage damage pattern significantly weakens the plant, often leading to reduced vigor or complete plant mortality in severe cases.

The biological cycle involves complete metamorphosis, consisting of egg, larva, pupa, and adult stages. Females lay eggs in moist, nutrient-rich soil. Upon hatching, larvae spend a significant portion of their life cycle underground, feeding and molting. The length of the development cycle can be influenced by environmental factors such as soil temperature, moisture levels, and the availability of food sources for the larval stage.

Damage symptoms usually manifest as uneven crop emergence, chlorosis, and sudden wilting of plants during dry periods. Because the root systems are compromised, plants cannot effectively absorb water and nutrients, which is fatal during critical growth stages. Farmers often identify the infestation by excavating the soil around symptomatic plants and observing the presence of characteristic C-shaped larvae.

Integrated Pest Management (IPM) strategies for Trochalus carinatus include several essential practices:

• Deep plowing to expose larvae to natural predators and environmental stress;
• Crop rotation with non-host plants to disrupt the life cycle;
• Application of soil-applied insecticides during the sowing process;
• Biological control methods involving beneficial entomopathogenic nematodes or fungi.