Storage pests of Sweet Sorghum:

Khapra (Trogoderma granarium)

This is another important pest that causes major damage in bulk storage conditions.

Nature of damage:

This pest damages the grain starting with the germ portion, surface scratching and devouring the grain. Actually, it reduces grain into frass. Excessive moulting creates public discrimination, loss of market appeal due to insanitation caused by the cast skins, frass, and hair. Crowding of larvae leads to unhygienic conditions in warehouses. Damage is confined to peripheral layers of bags or 30-45 ems in bulk storage.

Grains attacked:

This insect attacks the grains of wheat, maize, sorghum, pulses and oil seeds.

Identification:

• Adult size is 1.5 to 3 mm.

• Convex, oval in shape with practically no distinct division of head, thorax and abdomen.

• Abdomen size is comparatively larger.

• Males are smaller in size than females

• The larvae are straw colored.

• They have the hair with dark brown in color and the hairy bands are present on each segment and typical posterior tuft forming a tail of long hair. Size 4-5 mm.

Other information:

This insect can thrive at temperatures ranging from 23°C to 40°C. Under optimum conditions the insect can complete about 12 generations in a year. On starvation, the larva moults and reduces in size and becomes active again on availability of grain.

Hiding habits: The insect hides in cracks and crevices and is most distinctive. It is very difficult to kill these hidden insects even with contact insecticides.

Fig. 1 : Damage of Sweet Sorghum by Khapra beetel