What type of organism causes knots or galls on the roots of susceptible plants?

Nematodes are microscopic, worm-like organisms that can infect the roots of susceptible plants, leading to the formation of knots or galls. These galls occur as a result of the nematodes feeding on the plant tissue, which triggers a plant response that causes the tissues to swell. This swelling forms a structure that can disrupt normal plant function and lead to reduced growth and vigor.

The specific nematodes responsible for this issue are often root-knot nematodes, which create distinctive galls that you can identify on the roots of affected plants. These galls can be detrimental to the plant's health because they hinder nutrient uptake and overall root function. Understanding the role of nematodes is essential for effective pest management and horticultural practices, allowing for appropriate interventions to mitigate their impact on crops and garden plants.