Groundnut White Grub (Root Grub)

📖 Description

Groundnut White Grub (Holotrichia consanguinea), also called Root Grub or Chafer Grub, is one of the most destructive soil pests of groundnut, sugarcane and other crops across the Indian subcontinent, particularly severe in groundnut belts of Gujarat (Saurashtra), Rajasthan, Maharashtra, Karnataka and Andhra Pradesh where groundnut is grown on over 5 million hectares. The larva (white grub) is the destructive stage — it lives in soil and feeds on plant roots, severing them and causing characteristic wilting and ‘pull-up’ symptom (plants easily pulled from soil). The pest is particularly damaging because (a) it feeds underground where contact insecticides don’t reach, (b) it has a long life cycle (1-2 years for one generation), allowing grubs to feed for many months, (c) it attacks young seedlings which are most susceptible, and (d) it has a wide host range making rotation difficult. The adult beetle emerges at the onset of monsoon (June-July), feeds on tree leaves (neem, khejri, acacia), mates and lays eggs in soil — females can lay 40-50 eggs each. IPM with deep summer ploughing to expose grubs and pupae (most effective preventive measure), light trapping of adults (beetles are nocturnal and strongly attracted to light — mass trapping can significantly reduce egg-laying), soil application of biocontrol (Metarhizium anisopliae, Beauveria bassiana, EPN), crop rotation with non-host crops, and neem cake application provides effective control. The pest is most severe in sandy soils and in areas with continuous groundnut or sugarcane cultivation. Hand-collection of adult beetles at light traps during the brief adult emergence period (June-July) can significantly reduce egg-laying and subsequent grub damage.