Why do nematode-infested plants sometimes appear to be suffering from drought?

Nematode-infested plants often appear to be suffering from drought because the parasites severely damage the plant's root system, which is essential for water uptake.1

Nematodes feed by using a hollow, needlelike mouthpart called a stylet to puncture plant cells and inject digestive enzymes. This feeding process, combined with toxic salivary excretions, causes root tissues to become discolored, decayed, or abnormally enlarged, ultimately reducing the overall size and efficiency of the feeder root system.1

Because the root system is compromised, the plant loses its ability to effectively absorb water and nutrients from the soil. Consequently, even when soil moisture is adequate, the plant cannot transport enough water to its above-ground parts to maintain turgor pressure, leading to symptoms such as wilting on hot days, stunting, and a general lack of response to water and fertilizer.1