California Applicator License Category D Plant Agriculture Practice Test

Long-distance spread of plant-parasitic nematodes is mainly driven by human movement of infected plant material. When nursery stock is shipped, soil clinging to roots or soil in pots carries nematodes to new regions, where they can infest new crops. Water and wind can move nematodes, but over long distances they’re much less reliable vectors, and soil clumps or dust aren’t the primary means of widespread dispersal. So, nursery plants are the main route by which nematodes travel far from their origin.