What type of organism is primarily responsible for root rot in plants?

Root rot in plants is primarily caused by fungi. Fungi thrive in moist soil conditions and can attack the root system of plants, leading to decay and loss of function. This fungal infection interrupts the plant's ability to absorb water and nutrients, ultimately resulting in wilting, yellowing leaves, and potential plant death if not addressed.

While viruses can affect plants, they typically cause different types of symptoms and are not known to cause root rot directly. Bacteria can also cause root diseases, but they are less commonly associated with the type of decay known as root rot compared to fungi. Nematodes, which are microscopic roundworms, can cause damage to plant roots but are generally categorized separately from the root rot caused by fungal pathogens. Hence, fungi's role as the main agents responsible for root rot is well established in plant pathology.