The name “nematode” refers to any of several thousand species of parasite also commonly known as roundworms. While many species of nematodes are pests, some are actually beneficial to the garden. It is important to note that soil-borne and plant-loving nematodes are not the same species as the roundworms that sometimes inhabit humans and pets. One of the more frustrating aspects of dealing with nematodes is that the damage from nematodes closely resembles that of other pests and diseases, such as leaf yellowing and poor crop yield.
Dealing with a Nematode Problem
Nematodes are present at several layers of soil. The soil is separated into six horizontal layers known as “horizons”. Some nematodes are present in the topsoil, where they feed on plants and algae. Other nematodes live in the second layer of soil, where they feed on bacteria and fungi. Still, more nematodes are present in deeper layers of soil, where they feed on other nematodes and smaller organisms.
One way to identify a nematode problem is by the damage done to plants. Nematodes damage plants and other living organisms through their feeding process. Nematodes feed by puncturing the cell walls of the bacteria, fungi, or other pest and sucking out the internal goo. Another method they utilize is to attach themselves to the side of an organism and scrape away at the sides until they have penetrated the exterior.
When a nematode population is out of control, the affected crop will respond by swelling, showing distorted growth, and areas of the plant will begin to die. If you take a look at the roots of plants infested with nematodes, often times roots will have become swollen or knotted. Additionally, parasitic nematode presence can make affected plants susceptible to bacterial infections and viruses.
Unfortunately, nematodes are not visible to the naked human eye. They range from 1/50 to 1/20 of an inch in length and are typically translucent in color with unsegmented bodies. Nematodes are not closely related to true worms. Finally, nematode damage at the root level is most common in fruits and vegetables such as:
Nematode damage to leaves and stems is most common in some flowers such as chrysanthemums, onions, rye, and alfalfa.
Getting Rid of Nematodes
Nematodes can be controlled by maintaining a healthy population of beneficial nematodes (affiliate link). The term “beneficial nematodes” refers to several slightly different species of nematode who are not considered parasitic to the soil, but rather assist with the release of nutrients such as ammonium, as well as helping to irrigate the soil and destroy a diverse range of pests. Beneficial nematodes are much bigger than parasitic nematodes, at anywhere from 1/25 of an inch to several inches long. We highly recommend the addition of beneficial nematodes to your garden, as they are excellent for soil aeration, as well as for the control of unwanted garden problems, including harmful nematodes.
Ensure Well-Drained Soil
Nematodes are not very mobile on their own, but they move pretty freely in water and moist soil. It is important to keep your soil well-drained in order to help prevent nematodes as well as many other pests and diseases in the garden. Nematodes are also often spread by garden tools, boots, or any other objects that can carry dirt, including pets.
Use Beneficial Nematodes
When purchasing beneficial nematodes (affiliate link) for your garden, be sure to water the soil before and after application. Beneficial nematodes thrive in warm, moist soil. Also, bear in mind that different species of nematodes are preferred for different applications and to treat different pests and diseases. Make sure you are purchasing and applying the right nematodes for your garden.
The best way to ensure this is to separate nematodes into four groups:
- the first group of nematodes feeds upon bacteria,
- the second group feed on fungi,
- the third group are predatory – meaning they eat all kinds of nematodes and other smaller organisms,
- and the last group are omnivores, meanings they eat various types of organisms at different life stages.
A small number of the right type of nematodes for your garden can actually help your crops to flourish, but an overabundance of nematodes will prove harmful to the plants’ vitality.
Nematodes or roundworms are common in every garden, but they are not always unwanted visitors. While many nematodes can be destructive, a number of nematodes are beneficial and can help control the overall population. Thankfully, beneficial nematodes are simple to purchase and apply, just make sure you are choosing the right type for your garden’s conditions. Don’t hesitate to reach out if you have questions!