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Are Nematodes Bad for a Yard?

Nematodes are microscopic roundworms that have earned a somewhat dubious reputation. Although there are nematodes that damage turf, such as lesion nematodes (Pratylenchus spp.) , ring nematodes (Mesocriconema spp.) , root knot nematodes (Meloidogyne naasi and Meloidogyne spp.) , seed and leaf gall nematodes (Anguina pacificae), spiral nematodes (Helicotylenchus spp.) , bite nematodes (Belonolaimus longicaudatus) and stubby root nematodes (Paratrichodorus spp.) , there are also valuable nematodes that will help keep your lawn healthy.

Plant-Parasitic Nematodes

Plant-parasitic nematodes affect all sections of plants, however, the best numbers focus on the main systems. All these roundworms burrow into plant roots and masks, where they feed and multiply. Although they have a tendency to get the most press, only about 14 percent of all recognized nematode species are plant parasites. They are hard to control once existing, though pre-plant pesticides have also shown some promise.

Nematode Damage

Nematode damage often creates vague symptoms from grasses, such as yellowing in patches, stunting and lack of vigor. Turf may wilt or show signs of malnutrition despite adequate water and fertilizer. Crowns of annual bluegrass affected by seed and leaf gall nematodes will develop light-colored galls. Root symptoms caused by nematodes include galls, brown-black lesions and swollen and discolored root tips that limit further growth.

Soil Solarization

Soil solarization is an extremely successful control for ring nematodes, spiral nematodes and lesion nematodes, but supplies unpredictable control for some other nematodes. This technique is the most powerful when used yearly. You can solarize your garden in fall by preparing the dirt just like you normally would, then smoothing it out evenly. Spread a sheet of 1 to 2 mil clear plastic to the surface and then leave it for four or four to six weeks. This may heat the ground sufficiently to ruin many nematodes, as well as some soil-borne bacteria and fungi.

Beneficial Nematodes

Beneficial nematodes are the defenders of grass everywhere, whether or not they know it. All these nematodes, which can be found commercially, destroy insects like grubs which are damaging to lawns. Steinernema carpocapsae is a sit-and-wait forager, awaiting goal insects to come close before infesting. It infests armyworms and cutworms, in addition to the larvae of billbugs, black turfgrass ataenius, crane flies and lawn moths. A close cousin, Steinernema glaseri infests grubs. Heterorhabditis bacteriophora is a nematode that actively hunts for prey, seeking out the larvae of black turfgrass ataenius and fiery skippers as well as white grubs.

Applying Beneficials

Conscientious application of beneficial nematodes will increase their effectiveness against pests. The nematode you have selected should be implemented when you realize the pest insect is active, often throughout the spring and summer, though white grubs may be more active from the first fall. Successive applications are often needed to set up a strong colony of nematodes in a place. Nematodes thrive when implemented in the night to a moist ground that’s at least 60 degrees Fahrenheit and kept moist for many weeks.

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