Which one is a troublesome weed of agricultural fields ?

Options

A. Chenopodium album
B. Cyperus rotundus
C. Parthenium hysterophorus
D. Eichhornia crassipes.

Answer

To determine which plant is a troublesome weed of agricultural fields, we will analyze the provided options step by step.

1. **Understanding Weeds**: Weeds are plants that grow uncontrollably in agricultural fields, competing with crops for nutrients, water, and sunlight. They can hinder the growth of crops and reduce agricultural productivity.

2. **Analyzing the Options**:
- **Chinopodium album**: This is an annual fast-growing weed, but it is considered a weed only in certain regions. Thus, it may not be universally troublesome in all agricultural fields.
- **Cypress rotundus**: Known as Coco grass or Java grass, this is a type of grass but is not typically classified as a troublesome weed in agricultural contexts.
- **Parthenium hysterophorus**: Commonly known as Congress grass or carrot grass, this weed is notorious for its aggressive growth. It competes heavily for nutrients and is harmful to both crops and livestock due to its poisonous nature.
- **Econia cressips**: Also known as water hyacinth, this plant is primarily a weed in aquatic environments rather than agricultural fields.

3. **Identifying the Correct Answer**: Based on the analysis:
- Chinopodium album is not universally troublesome.
- Cypress rotundus is not considered a significant agricultural weed.
- Parthenium hysterophorus is a well-known troublesome weed that negatively impacts agricultural fields.
- Econia cressips is not relevant to agricultural fields.

Thus, the correct answer is **Parthenium hysterophorus**.