LESSER GRAIN BORER

Scientific name: Rhizopertha   dominica

Commodities attacked:

Paddy ,Rice,Wheat,and Maize.It is able to attack paddy more easily than S.Oryzae.

Nature of damage :

Adult comes out from the grain leaving a irregular hole.In bagged  irregular messy flour spots indicate infestation of this pest.heating is very common. Localized infestation is almost a rule.Both adults and larva cause damage and are voracious feeders.As such gain kernels are reduced to mere shells.The damaged kernels remain engulfed in a film of waste flour.

Identification:

1. Most characteristic feature is that the head is deflexed downwards to such an extent that it is almost hidden in a dorsal view. 
2. There is a prominent constriction between pro thorax and elytra.
3. Colour ranges from brown to blackish.
4. Antenna has a large loose three segmented club.
5. Size 3 m.m.

Life history and habits:

Eggs are laid on the surface or interstices of of cereal grains singly or in clusters.Single female lays eggs upto 550.The larvae eat their way  into the grain or feed on grain dust or starchy material and are capable of attacking grain externally.The free living larva normally enters the grain after the third instar for pupation.

Entire life cycle takes 25 days under optimum conditions.Ideal climatic conditions range from 34-36 degrees centigrade with R.H above 50-60 %.Adults are good fliers but they are not capable of field infestation as the larva are free living.The insect prefers dark,dingy stores.Infestation in bagged storage is not normally confined to periphery.