Question

Insect resistance in the host crop plants may due to

• A. physiological characteristics only
• B. morphological and physiological characteristics only
• C. biochemical characteristics only
• D. morphological, biochemical and physiological characteristics

Answer 1

The correct option is D morphological, biochemical and physiological characteristics

Agricultural pests are organisms that attack agricultural crops and destroy them, leading to huge crop losses. Some crop plants naturally develop resistance to pests as a result of morphological, physiological or biochemical characteristics in them.

Some examples are listed below:

• Presence of hairy leaves provides resistance against jassids (sap-sucking insects) in cotton and cereal leaf beetles in wheat. Wheat varieties with strong solid stems are not preferred by stem sawfly (insect). These are morphological adaptations that provide pest resistance.
• Nectar is a sweet sugary fluid secreted by special glands called nectaries present in the plant. Nectar often attracts insects towards the plant as the insects feed on it. Nectar-less varieties of cotton do not attract bollworms, a common pest that infests cotton plants. This is a physiological adaptation that provides pest resistance.
• In maize crops certain biochemical characteristics like low nitrogen, low sugar and high aspartic acid content helps resist against maize stem borers.