Which part of the tobacco plant is infected by Meloidogyne incognita?A. FlowerB. LeafC. StemD. Root

The correct answer is: D. Root
Meloidogyne incognita, commonly known as the root knot nematode, is a parasitic nematode that primarily infects the roots of plants, including the tobacco plant.
1. Root Infection:
o Meloidogyne incognita infects the roots of various plants, causing the formation of galls or knots at the root tips. These galls are the result of the nematodes feeding on the root tissues and disrupting normal growth.
o The nematode enters the roots through the root tips and establishes feeding sites, which causes damage to the root system, affecting nutrient and water uptake.
o Infected plants may show symptoms such as stunted growth, yellowing of leaves, wilting, and reduced yield, as the nematode infestation weakens the plant's ability to absorb essential resources.
2. Effect on Tobacco:
o Tobacco plants are susceptible to root knot nematode infections, leading to reduced plant vigor and poor crop yields. The galls formed on the roots can interfere with the plant’s nutrient and water absorption, making it difficult for the tobacco plant to thrive.
Why Other Options Are Incorrect:
1. A. Flower:
o Meloidogyne incognita does not infect the flower of the tobacco plant. It specifically targets the root system.
2. B. Leaf:
o Root knot nematodes do not infect the leaves of the plant. They are root parasites and do not cause direct damage to aerial parts like leaves.
3. C. Stem:
o While some plant pathogens may affect the stem, Meloidogyne incognita does not infect the stem of the tobacco plant. Its primary site of infection is the roots.
Meloidogyne incognita primarily infects the roots of tobacco plants, making D. Root the correct answer.