TUBER VEGETABLES :: MAJOR PESTS :: WHITE GRUBS

3. White grubs: Holotrichia excisa, H. repetita, H. notaticollis, Anomala communis, A. nathani (Melolonthidae : Coleoptera)
Host range: Potato, groundnut and sugarcane.  
Distribution and status: All over India
Damage symptoms: Grubs feed on roots and tubers; Adults feed on foliage during night; damage more during autumn.
Bionomics
Eggs are laid in the soil near host plants. On hatching, grubs feed on developing roots and tubers of potato as well as other grasses growing around. When full-fed, grubs over winter deep down in the soil. Grubs are C shaped with orange head. Adults emerge as soon as temperature starts rising, but continue to remain in the soil till onset of monsoon. Adults feed on foliage during night and damage is more during autumn. Holotrichia adults are brown beetles with pale thorax. Anomala adults are smaller than Holotrichia and are pale-yellowish.

IPM

• Do summer ploughing to expose pupae and adults
• Dust endosulfan 4% or quinalphos 5% D at 25 kg/ha 10 days after first summer rains
• Install light traps between 7 PM and 9 AM in April-May months
• Do presowing soil application of entomogenous fungus Metarhizium anisopliae1 ´ 10 FIB/g during May @ 20 kg/ha and fork the soil
• Hand pick adult beetles in the morning
• Hand pick 3rd instar grubs during July-August
• In endemic areas, apply phorate 10 G at 25 Kg/ha during autumn (August-October)