Correct Option
The correct option is (c) 1 and 3 only.
Explanation
Insect pests infest crop plants and cause damage through specific modes of feeding. These modes are categorized based on the insect's mouthparts and how they interact with plant tissues to obtain nutrition.
Statement-wise Analysis
- Statement 1 is Correct: Many insect pests, known as chewing or biting insects, possess mandibles adapted for cutting and consuming solid plant material. They damage the plant by cutting roots, stems, and leaves. Examples include locusts, beetles, and caterpillars.
- Statement 2 is Incorrect: Sucking pests (such as aphids, leafhoppers, and plant bugs) pierce plant tissues to extract cell sap. This process deprives the plant of essential water and nutrients. Pests feed on the plant; they do not provide nutrients to it.
- Statement 3 is Correct: Certain pests, known as borers, enter the plant body and tunnel through internal tissues. They bore into stems, fruits, and seeds to feed and live inside, causing significant structural damage. Examples include the sugarcane stem borer and cotton bollworm.
Key Takeaway: Insect pests damage plants primarily by cutting plant parts, sucking cell sap, or boring into stems and fruits. In all cases, they deplete plant resources or destroy tissues.