Worms controllable but not preventable

Question: I recently pulled up the remains of my tomato plants and found the roots disfigured, but I could not see any worms on the roots. I planted tomatoes that had a VFN designation on the label and thought they were resistant to nematodes. Are these the remains of nematodes?

Nematodes are microscopic worms, so you would be unable to see them with your naked eye. Just because they have the label nematode resistant ("N" of "VFN") doesn't mean you can't get them. It just means that the plants can resist infestations but are not immune to them.

From your picture, it does look like a nematode attack. Remember that you should rotate the locations of where you plant vegetables each year. This will help keep diseases and nematode populations from building in certain spots.

However, nematodes are a different problem. There are a few things you can do, and one is solarizing your soil. This technique will help reduce the population of nematodes. Continue to use vegetables with an N designation.

You can plant cover crops such as ones that have been shown to suppress nematodes, including cowpea, rapeseed, velvet bean and sudangrass.

Another technique is to keep your crops outgrowing the nematode attack by keeping them well-fertilized and healthy.

Bob Morris is a horticulture expert living in Las Vegas. Visit his blog at xtremehorticulture.blogspot.com.