Which management practice is least effective against nematodes?

Crop monoculture is the practice of growing a single crop species over an extensive area for many consecutive seasons. This approach can create a favorable environment for nematodes, as it allows their populations to build up without interruption. Since nematodes are pests that can thrive in consistent cropping conditions, monoculture can exacerbate their impact on crops, leading to increased damage and reduced yields.

In contrast, practices like crop rotation and cover cropping disrupt the life cycles of nematodes. Crop rotation involves alternating different crops in the same area across seasons, which can help reduce nematode populations by introducing crops that are less susceptible to them. Cover cropping can improve soil health and may also enlist plant species that nematodes find unfavorable, thus suppressing their populations. Soil fumigation can directly eliminate nematodes in the soil when properly applied.

Therefore, crop monoculture is the least effective management practice against nematodes since it does not provide any natural control or disruption of their life cycle, leading to potential increases in their populations over time.