Question

Which of the following is not a sucking pest?

• A. Aphids
• B. Plant hoppers
• C. Thrips
• D. White grubs

Hint:

Remember that sub-surface soil pests like white grubs, cutworms, and termites are typically chewing pests that cut or feed on root systems.
Sucking pests are mostly foliage-feeding insects belonging to the orders Hemiptera and Thysanoptera.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Agricultural insect pests are classified based on their feeding habits and mouthpart structures.
This classification determines the type of damage they cause and the choice of insecticide (e.g., systemic insecticides for sucking pests, contact insecticides for chewing pests).

Step 2: Detailed Explanation:
Let us analyze the pests listed in the options:
- Aphids (A): Possess piercing-sucking mouthparts (proboscis). They pierce plant vascular tissues (phloem) and suck out sap, causing leaf curling and excreting honeydew.
- Planthoppers (B): Also have piercing-sucking mouthparts. They suck sap from the leaf sheaths and stems, causing "hopper burn."
- Thrips (C): Have rasping-sucking mouthparts. They rasp the plant tissue surface and suck the exuded sap, causing silvery leaves.
- White grubs (D): These are the larval stages of scarab beetles (such as Holotrichia consanguinea).
They live underground in the soil and possess strong, well-developed biting and chewing mouthparts (mandibles).
They feed directly by chewing and destroying the roots of crops (like groundnut or sugarcane), leading to wilting and death of the plant.
Therefore, white grubs are chewing pests, not sucking pests.

Step 3: Final Answer:
White grubs is not a sucking pest.