Question

Pyrethrum is a natural insecticide derived from _ _ _ _ .

• A. Azadirachta indica
• B. Chrysanthemum cinerariifolium
• C. Citronella silvatica
• D. Nepeta cataria

Hint:

Pyrethrum = Pyrethrins = Chrysanthemum cinerariifolium. This association is frequently asked in pharmacognosy examinations.

Answer 1

The Correct Option is B

Concept: Pyrethrum is one of the most important natural insecticides used throughout the world. It contains a group of active compounds known as pyrethrins, which exhibit potent insecticidal activity while showing relatively low toxicity to mammals. Because of these properties, pyrethrum has gained significant importance in agriculture, public health, and household pest control. The source plant belongs to the family Asteraceae and its dried flower heads contain the active insecticidal principles.

Step 1: Understand what pyrethrum is.
Pyrethrum refers to the powdered flower heads of a specific species of chrysanthemum. The active constituents present in these flowers are pyrethrin I, pyrethrin II, cinerin, and jasmolin compounds. These compounds act on the nervous system of insects, causing rapid paralysis and death.

Step 2: Identify the botanical source.
The botanical source of pyrethrum is Chrysanthemum cinerariifolium. The dried flower heads of this plant are harvested and processed to obtain pyrethrum powder or pyrethrin extracts.

Step 3: Analyze the incorrect options.
Azadirachta indica is Neem, which contains azadirachtin and acts as a botanical pesticide, but it is not the source of pyrethrum. Citronella species are mainly known for their essential oils and mosquito-repellent properties. Nepeta cataria (Catnip) contains nepetalactone and has insect-repellent effects but is not the commercial source of pyrethrum. Conclusion: Pyrethrum is obtained from the dried flower heads of Chrysanthemum cinerariifolium. Therefore, the correct answer is Option (B).