Storage pests of Sweet Sorghum

Grain Moth (Sitotroga cerealella)

The grain moth is commonly known as Angoumois grain moth.

Nature of damage:

It is a primary pest. Only the larval stage is damaging while the adult stage is harmless. Grains are hollowed out. The infestation can occur in the field also. In stored bulk grain, infestation remains confined to upper 30 ems depth only. The hole made by the insect is circular in shape with characteristic 'flap ' or 'trap door '.

Grains Attacked:

Grain moth affects mainly the grains of paddy, maize and sorghum. The insect cannot attack milled rice or other cereal products.

Identification:

• Size of the insect ranges from 8 to 1 0 mm

• Moth has dirty yellowish brown color

• The wings are completely folded over the back in a sloping manner

• The wings can expand to a width of 1 0-14 mm

• The hind wings have a sharp pointed apical end, bearing a heavy fringe of bristles

• The insect leaves small dirty specks on windowpanes and walls.

Other information:

The female lays singly about 100 white eggs in stores or field on the surface of damp grains, which soon become red. In grains with less than 12 per cent moisture content there is practically no development. The insect is quite susceptible to low temperature ranges. Thus the damage of this insect is more serious in the grains of Kharif crops only. It can also attack rabi crops when grains are affected by rain before harvest or immediately after harvest.

Fig. 1 : Grain moth damage