The names of the plant pathogens and their taxonomic groups are given in the table:

Plant Pathogen	Taxonomic Group
A. Phytophtora infestans	i. Bacteria
B. Cladosporium fulvum	ii. Oomycetes
C. Ralstonia solanacearum	iii. Nematodes
D.  Heterodera schachtii	iv. Fungi

Choose the option with all the correct matches:​

Correct option is A

To correctly classify the given plant pathogens, let's analyze each one:

• A. Phytophthora infestans → Oomycetes (ii) 

  • Phytophthora infestans is the causative agent of late blight in potatoes and tomatoes.
  • It belongs to the Oomycetes (water molds), which resemble fungi but are classified as protists.

• B. Cladosporium fulvum → Fungi (iv) 

  • Cladosporium fulvum (also known as Passalora fulva) causes tomato leaf mold disease.
  • It is a fungal pathogen belonging to the Ascomycota division.

• C. Ralstonia solanacearum → Bacteria (i) 

  • Ralstonia solanacearum is a soil-borne bacterial pathogen that causes bacterial wilt in a variety of crops (potato, tomato, and banana).
  • It belongs to the Proteobacteria group.

• D. Heterodera schachtii → Nematodes (iii) 

  • Heterodera schachtii is a plant-parasitic nematode, commonly known as the beet cyst nematode.
  • It affects sugar beet crops by invading roots and causing yield losses.

Thus, the correct matching is:

• A - ii, B - iv, C - i, D - iii (Option 1).

Information Booster

1. Oomycetes vs. Fungi: Oomycetes (e.g., Phytophthora infestans) were historically classified as fungi but are now known to be closer to algae due to their cellulose cell walls.
2. Bacterial Wilt: Caused by Ralstonia solanacearum, it is a major plant disease affecting crops like tomatoes, bananas, and potatoes.
3. Nematode Pathogens: Heterodera schachtii belongs to cyst nematodes, which can persist in the soil for years, making them difficult to control.
4. Fungal Leaf Mold: Cladosporium fulvum is an airborne fungal pathogen that thrives in humid conditions and affects tomato leaves.
5. Economic Impact: These pathogens cause significant crop losses globally, necessitating effective disease management strategies.
6. Disease Control Methods: Include crop rotation, resistant varieties, biological control, and chemical treatments.
7. Historical Importance: Phytophthora infestans was responsible for the Irish Potato Famine in the 19th century, highlighting the impact of plant pathogens on food security.