Nematodes are microscopic roundworms that live in the soil and can be found in most lawns. Some nematodes are beneficial, feeding on bacteria, fungi or other microscopic organisms. However, other nematodes are harmful to plants because they feed on the plant tissues and cause plant damage. These plant-parasitic nematodes feed on the roots by puncturing the plant tissue and ingesting plant fluid. Some nematodes remain in the soil (ectoparasitic) while they feed and others (endoparasitic) crawl inside the root tissue to feed.
As nematodes feed, they cause damage to the roots reducing the ability of the plant to obtain water and nutrients from the soil. When nematode populations get high enough, or when environmental stresses such as high temperatures or drought occur, symptoms may become evident. These symptoms include yellowing, wilting, browning, thinning or plant death. The damage usually occurs in irregularly shaped patches that may enlarge slowly over time. Similar conditions may be caused by other factors such as soil condition, fungi or insects as well.
Here are the most common nematodes that damage southern turfgrasses.
Lance- St. Augustine, Zoysia and Burmuda
Sting- Zoysia, Burmuda and Centipede
Stubby-Root- St. Augustine
Root-Knot- Zoysia
Ring- Centipede
What can I do if my lawn has nematodes?
Many of the highly effective nematicides used in the past are no longer available because of their risk to humans and the environment. There are a few “organic” products that claim to suppress nematodes in home lawns. However, there is no field effectiveness data conducted by credible scientists that indicate they work.
There is one product that is labeled for home lawns and it uses a bacterium to help suppress nematodes. This bacteria (Bacillus firmus) colonizes the root system and produces compounds that protect the root system from nematodes. However, timing is critical to achieve good results with this product and repeat applications, 4-8 weeks apart, are necessary. This bacteria does not kill nematodes, it only protects the roots, and should not be used to “fix” an existing nematode problem.
The best way to manage a nematode problem is by improving overall plant health and avoiding other stresses on the grass. Grass that is given proper water and fertilizer can often withstand higher levels of nematode infestation. Depending on what nematodes are present, replacing with a different turf type might also be an option or replacing turf with an alternative groundcover could be beneficial.
Call Baldin Turf Lawn & Landscape, Inc. for all your Lawn Care needs. (850)897-3073 Niceville (850)832-4212 Panama City Beach