White Grub
Holotrichia serrata
📖 Description
White Grub, the larval stage of the rhinoceros beetle Holotrichia serrata and related species, is a major soil pest across the Indian subcontinent, causing extensive damage to sugarcane, groundnut, and other crops. Adult beetles emerge with the first monsoon rains (May-July), feed on tree leaves at night, and lay eggs in soil. The C-shaped white grubs feed on plant roots and underground stems for 2-3 years, weakening plants, reducing nutrient uptake, and causing wilting and lodging. White grub infestations are sporadic but devastating — entire fields can be destroyed in outbreak years. Soil application of entomopathogenic fungi (Metarhizium, Beauveria) has emerged as an effective biological control strategy that suppresses grub populations over multiple seasons.
⚠️ Symptoms to watch for
- Yellowing and wilting of plants, eaten roots and underground stems, lodged sugarcane, dead patches in fields, plants easily pulled out, beetles feeding on tree leaves at night, reduced tuber and pod yield
🩹 Treatment
- Apply entomopathogenic fungi (Metarhizium anisopliae) @ 5kg/ha in soil, set up light traps @ 1/ha for adult beetles, apply neem cake @ 250 kg/ha as basal, handpick beetles from trees at night, use recommended soil insecticides
🌿 Organic treatments
- Apply Metarhizium anisopliae @ 5 kg/ha in soil, apply Beauveria bassiana @ 5 kg/ha in soil, set up light traps @ 1/ha for adult beetles, handpick beetles from trees at night, apply neem cake @ 250 kg/ha as basal, apply Steinernema carpocapsae entomopathogenic nematodes, flood fields to expose grubs
🧪 Chemical treatments
- Phorate 10 G @ 15 kg/ha in soil, Carbofuran 3G @ 25 kg/ha in soil, Chlorpyrifos 20 EC @ 5 ml/L soil drench, Imidacloprid 17.8 SL @ 1 ml/L drench at base, Quinalphos 25 EC @ 2 ml/L spray on tree hosts of adults
🛡️ Prevention
- Deep plough after harvest to expose grubs and pupae to predators and sun, set up light traps during adult emergence (May-Jul), handpick beetles from trees at night, rotate with non-host crops, plant early before grub peak, use entomopathogenic fungi in soil, remove alternate hosts (Acacia, Neem trees where adults congregate), apply neem cake as basal
🪴 Affected plants
- Sugarcane, Groundnut, Maize, Sorghum, Pulses, Wheat, Potato, Vegetables, Coconut Seedlings, Many Crops
🦋 Natural predators
- Birds, Moles, Ground Beetles, Spiders, Frogs, Parasitic Wasps, Entomopathogenic Fungi
🌱 Host plants
- Saccharum officinarum, Arachis hypogaea, Zea mays, Solanum tuberosum, Cajanus cajan
🔄 Lifecycle
- Adult beetles emerge with first monsoon rains (May-Jul) and live 30-60 days.
- Females lay 30-50 eggs in soil.
- Eggs hatch in 10-15 days.
- Grubs feed on roots for 2-3 years, passing through 3 instars.
- Pupation occurs in soil in an earthen cell, lasting 15-30 days.
- Adults emerge next monsoon.
- Complete life cycle 1-3 years depending on species and conditions.
📅 Season
- Adults emerge May-Jul with monsoon rains, grubs active year-round in soil, peak crop damage Aug-Feb
🔎 Appearance
- Adults are reddish-brown oval beetles.
- Larvae (grubs) are creamy-white, C-shaped with a brown head and six legs on the thorax, found in soil.
- Pupae are pale yellowish-brown found in earthen cells in soil.
💥 Damage level
- High
🔁 Reproduction rate
- Slow
🗺️ Geographic regions
- Indian Subcontinent
- Southeast Asia
Have an Insect to Identify?
Upload or take a photo of an insect on your plant and our AI will identify it and recommend treatments.
📷 Diagnose from Image