Q&A for How to Kill Nematodes

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Solarization works by heating the soil to a depth of 6-8 inches. To heat the soil that deeply with a torch would be difficult, time-consuming, dangerous, and unreliable, as you would have to guess whether the soil had been heated far enough. Solarization is a more reliable, tested method to reduce nematode populations.

Nematodes are usually not spread through cuttings rooted in water, they are only spread through infected soil (dirty shoes, garden tools, gloves, pots, etc). If the nematodes are attacking the stem of the plant, take cuttings from above the infected area to ensure you don't take nematode eggs, and plant the rooted cutting in a pot to avoid spreading nematodes to in-ground garden areas to be safe. Compost tea made with mustard leaves or other brassica leaves (such as cabbage, kale, collards, or radish) may be able to kill or reduce nematode populations. Use this method if you wish to save the original, infected plant.

To control foliar nematodes on your Solomon’s Seal, remove and destroy infected leaves instead of composting them. Improve air circulation by thinning plants and water at the base to reduce moisture. If possible, solarize the soil with clear plastic in summer, rotate crops, and consider nematode-resistant plants. Growing marigolds can help suppress nematodes. Use beneficial nematodes, neem oil, or diluted hydrogen peroxide spray for control. Since your area is shaded, keeping foliage dry is necessary.

Yes, as long as the nematodes used are safe for plants. Nematodes are often applied to control pests like wireworms or root-knot nematodes. Wait a few days to a week after applying nematodes before planting, allowing time for them to work. The specific nematodes should target pests and not your crops. Follow the nematode product instructions for best results.

No, Nematocera, an infraorder of insects including mosquitoes, gnats, and midges, do not infect the human scalp. These insects might bite or irritate the skin but do not live on or infect the scalp like other parasites, such as lice.

Soil solarization can help reduce a variety of soil-borne pests, including some insect larvae, by using heat from the sun to raise the soil temperature. While it may help with wireworms to some extent, it’s not guaranteed to completely eradicate them, especially since wireworms can burrow deep into the soil where temperatures might not reach high enough to kill them. In Southeast Texas, with its hot summers, solarization could be more effective due to the intense heat, but it might still require additional methods to fully control wireworms, like crop rotation, using nematodes that target wireworms, or applying specific insecticides.

To effectively kill nematodes in the soil using heat, the temperature should reach 125–140°F (52–60°C) for at least 30 minutes. Nematodes may be found as deep as 12–36 inches (30–90 cm), depending on soil type, moisture, and species. However, most plant-parasitic nematodes remain in the top 6–12 inches (15–30 cm) where plant roots are most abundant.

Yes, planting mustard and allowing it to mature before tilling it into the soil can help reduce nematode populations. This method is known as biofumigation and works because mustard plants release natural compounds called glucosinolates, which break down into isothiocyanates when the plant matter decomposes. These compounds are similar to the active ingredients in some commercial nematicides and can be toxic to nematodes.