Question

Parthenium is controlled by which one of the following weeds?

• A. Cynodon
• B. Portulaca
• C. Cassia
• D. Gomphrena

Hint:

Botanical control of Parthenium: Competitive displacement by Cassia sericea Cassia tora. Biological insect control: Zygogramma bicolorata (Mexican beetle).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Biological weed displacement (allelopathic suppression) utilizes competitive non-hazardous plant species to suppress invasive noxious weeds.

Step 2: Detailed Explanation:
Parthenium hysterophorus (carrot grass/congress grass) is an aggressive, invasive alien weed causing severe allergic dermatitis, asthma, and agricultural crop yield loss.
Cassia sericea (syn. Cassia uniflora) and Cassia tora are non-invasive leguminous plants that naturally outcompete and displace Parthenium through rapid canopy growth and the exudation of allelopathic phytotoxins.

Step 3: Final Answer:
Therefore, Parthenium is controlled biologically by Cassia, corresponding to option (C).