Nematodes nearly impossible to nullify

Question: Last fall, I pulled one of my cucumber plants. One of the plants definitely had strange roots, which I am almost positive were caused by root-knot nematodes. Are these nematodes harmful to humans and my dog? Will it give me a disease or worm if I touch the soil? Can I plant any other vegetables in the same raised bed? I was also thinking of maybe removing the soil from the raised bed and moving it to the big pots where I will be planting citrus plants.

Nematodes are very tough to get rid of if you have them. I should say they are basically impossible to get rid of. Be careful and do not move soil from this spot to other areas, such as your citrus pots, or you will move the nematodes as well.

Nematodes infest only plants, not animals, so all animals are safe around these guys. Soil solarization will help knock back the populations but not get rid of them. There are some products such as Clandosan (a natural product) that are supposed to help, but I would not be too optimistic. Use vegetables that are nematode-resistant and fruit trees on rootstocks that resist nematodes. Nematode-resistant rootstocks for fruit trees include Nemaguard, Citation, Viking, Atlas, Myrobalan and Marianna.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at Visit his blog at For more, check the Home section of Thursday’s Las Vegas Review-Journal.