Nematodes are microscopic round worms that live in the soil. There are beneficial nematodes and highly destructive varieties. Most nematodes live in or near plant roots because that’s what they like to eat. Often, they are carried into the garden on shoes and tools.
There are many types of nematodes. The most common Bad Guys are:
There are not many above ground symptoms, so identifying nematode infestations can be difficult. If you notice wilting during the warmest part of the day, even though the plants have enough moisture, lack of vigor, or chlorosis (yellowing leaves), it is time to take a look at the root system.
To examine the root system, gently pull out the plant, breaking up the soil around the roots, and then rinsing the roots off under running water. Then take a close look at the roots. If you see swollen areas, called galls, there may be a nematode problem. These galls are usually small, but they can be as big as one inch in diameter. Roots may also appear deformed or abnormally shortened.
Once nematodes are present, crop rotation and allowing the ground to go fallow for a season are the best treatments. Non-susceptible crop varieties should be planted for 3-5 years to completely starve out a nematode population. Leaving an area unplanted (fallow) for one year will also work, as long as the soil is kept moist enough for nematode eggs to hatch. Once they hatch, there won’t be enough food and they will starve.
Planting resistant varieties is another way to defeat nematodes. Look for tomato varieties with the code VFN on the label.
You can grow a surprising amount of food in your own yard. Ask me how!