Managing Nematodes on Your Florida-Friendly Lawn

Having a Florida-friendly lawn is certainly something to brag about, but keeping it looking and feeling good requires plenty of maintenance and preventative care. One of the dangers for turf grass is nematodes, or microscopic, worm-like organisms that are out for your lawn’s roots. We’re here to provide everything you need to know to identify, understand, prevent, and even neutralize the threat of harmful nematodes.

What are Nematodes?

Nematodes are unsegmented roundworms that are very small when living in the soil; most can only be seen with the aid of a microscope. While most of these soil nematodes are beneficial because they feed on harmful bacteria, fungi, or other microscopic soil organisms, there are others that are harmful to plants because they feed on plant tissues and can destroy a Florida lawn. All of the plant-parasitic nematodes that are pests for turf grass feed on or inside of roots.

Grass Damage Caused by Nematodes

Plant-parasitic nematodes damage the roots as they feed, which reduces the ability of the grass to obtain water and nutrients of the soil. Roots that have been damaged by nematodes may be abnormally short and stubby, or they may appear darkened or rotten. If the population densities get high enough or environmental stresses (high temperature, drought, etc.) occur, aboveground symptoms may become evident. The clearest symptoms include yellowing, wilting, browning, thinning, or even plant death.

When Nematodes Become a Problem

Just like with any plant, grass, or soil issue, diagnosing accurately is the best way to address the problem and avoid wasting effort or applying unnecessary pesticides, which could cause further damage. There are professional nematode diagnostic labs that specialize in determining whether plant-parasitic nematodes are involved in a turf problem; it’s suggested that you get a sample tested by one of these facilities.

The following guidelines should be followed to ensure the most accurate lab diagnosis possible:

1. Take soil from 10-15 locations to a depth of 3-4 inches and combine it to make a single sample. This is necessary because nematodes are not evenly distributed in a lawn, and tend to clump into hot spots. In total, a pint of soil from your lawn is an appropriate sample size.
2. Don’t forget to take samples from areas where the grass is sick, and not necessarily dead. If there is damage in a number of areas on your lawn, take a few cores from the border of affected areas to include in the sample. Using a “zig-zag” pattern across the turf grass is best.
3. Put the combined soil from the lawn into a plastic bag and seal it. Don’t use paper bags.
4. Keep the samples out of sunlight, and in an air-conditioned room until they’re sent off to the professionals. Nematodes are highly sensitive to high temperatures and UV light. Don’t leave samples on the dashboard of your car or in the back of a pickup truck, because this can kill them quickly and can negatively affect the accuracy of the diagnosis.
5. Submit the sample right away. Next day delivery is the best way to obtain accurate results and diagnosis.

What You Can Do About Nematodes

Traditional nematicides that have been used and proven successful in the past are not an option any more because of their risks to humans and the environment. There are products available for use on home lawns that are specially marked as “organic,” “biological,” or “non-toxic” that claim to be suppressive to plant parasitic nematodes. If you’re going to purchase one of these, know that there is currently no field effectiveness data conducted by credible scientists that indicates that they work.

Going organic is certainly an effective option, however, in the form of compost, mulch, municipal sludge, and manure, all of which can help the grass tolerate nematode damage. Combined with best practices such as proper watering and fertilization, these organic options are the best way to treat a nematode issue.

Treatment of your Florida-friendly lawn should be aimed at increasing the ability of the grass to tolerate nematode damage. Avoiding stress, promoting root vigor, and choosing tolerant grasses are just few of the best strategies.