PESTS OF SORGHUM :: Minor Pests :: Ash Weevils

18. Ash weevils:  Myllocerus maculosus , M.viridanus, M.subfasciatus & M. discolor (Curculionidae: Coleoptera)

Distribution and status: Throughout India

Host range: Bajra, maize, sorghum, pulses, groundnut, cotton, guava

Damage symptoms: Leaf margins are notched resulting in wilting of plants in patches.  Plants come off easily when pulled.  Roots are eaten away by grubs.  Adult feed on leaves.

Bionomics
M.viridanus: Adult weevil with greenish white elytra

M. maculosus: Adult weevil with greenish white elytra having dark lines.

M. discolor: Adult weevil is brown with white spot on elytra.  Grub is small, white apodous and found feeding on roots. Weevil appear during summer and lay ovoid, light yellow eggs in the soil. Female lays on an average 360 eggs over a period of 24 days. Eggs hatch in 3-5 days. Grub period 1-2 months, pupate in soil inside earthern cells and pupal period  is 7-10 days. Life cycle is completed in 6-8 weeks. There are 3-4 generations in a year.Adults live fairly long for4-5 months in the winter. 
 
M. subfasciatus: The adult weevil light grayish to white with four black spots on the wing covers. The eggs are light yellow and laid deep in the soil. The grubs are fleshy, yellow-colored. Pupation occurs in earthen cells in the soil. Egg, larval, and pupal periods last for 3 - 11, 3-42, and 5- 7 days respectively.

M. viridanus	M. subfasciatus	M. discolor

Management
1. Pest can be suppressed by disturbing the soil upto a depth of 7.5 cm and destroying the   immature stages
2. Spray 2.5 kg carbaryl 50 WP in 500 L of water/ha