Nematodes can spread plant diseases primarily through what mechanism?

Nematodes are microscopic roundworms that can play a significant role in the spread of plant diseases. The primary mechanism by which they do this is through infected soil or plants. When nematodes are present in the soil, they can invade plant roots, leading to various physiological effects that ultimately result in disease. This interaction not only damages the plants but also allows for the transmission of pathogens like bacteria and fungi that may be present within the nematodes themselves or in the soil.

Moreover, nematodes can lead to root galls, lesions, and other forms of plant stress, making the plants more susceptible to secondary infections by pathogens. This connection establishes a direct pathway for disease spread, as infestations can lead to a decline in plant health, influence crop yields, and even lead to plant death.

In contrast, while infected seeds and animal carriers can contribute to disease spread in some contexts, they are not the primary mechanism for nematodes. Natural fertilizers, likewise, do not serve as a direct route for nematodes to cause disease, although they can sometimes introduce nematodes into a garden or agricultural field if not processed properly. This context helps clarify the dominant role that soil and plant interactions play in the life cycle of nematodes