Question

Khapra beetle is

• A. Primary internal pest
• B. Secondary pest
• C. Primary pest, can damage both internally and externally
• D. Primary, external pest

Hint:

Primary Feeders:
Internal $\rightarrow$ Rice weevil, Lesser grain borer, Pulse beetle, Angoumois grain moth.
External $\rightarrow$ Khapra beetle.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Stored product pests are classified as primary or secondary pests depending on their ability to damage sound, unbroken grains.
They are further categorized as internal or external feeders based on where the larval feeding takes place.

Step 2: Detailed Explanation:
Let us analyze the biological feeding habits of the Khapra beetle, Trogoderma granarium:
A primary pest is an insect that can attack and damage whole, intact, undamaged grains.
A secondary pest can only feed on broken grains, dust, or grains already damaged by primary insects.
An internal feeder is a pest whose larva develops entirely inside the seed kernel (e.g., Sitophilus oryzae, Rhyzopertha dominica, or Sitotroga cerealella).
An external feeder is a pest whose larva feeds on the outer surface of the grain, or consumes the germ portion from the outside.
The Khapra beetle larvae are highly destructive primary pests because they can easily attack healthy, unbroken grains.
However, the larvae do not live or feed inside the grain kernel.
Instead, they feed externally on the grain surface, specifically targeting the embryo or germ portion of the seed first, before moving to the endosperm.
Therefore, the Khapra beetle is classified as a primary, external pest.

Step 3: Final Answer:
The Khapra beetle is classified as a Primary, external pest.