How do plant parasitic nematodes usually cause damage to crops?

Plant parasitic nematodes primarily damage crops by feeding on the roots. These microscopic roundworms invade plant roots and extract nutrients, which can weaken the plant's structure, disrupt its ability to absorb water and nutrients, and create openings for disease pathogens to enter. The feeding activity of nematodes leads to root galls, lesions, or malformations, which can significantly reduce plant vigor and yield. This root damage is particularly detrimental because healthy roots are essential for a plant's overall health and productivity.

While the other options involve parts of the plant that can be affected by different types of pests, nematodes are specifically root feeders, making their impact on the roots critical for understanding their role in crop damage.