Root-Knot Nematodes—The “Cancer” of Vegetables That Grieves Farmers [Part II]

For vegetable growers, root-knot nematodes are a particularly difficult pest to manage, requiring systematic measures for effective control. The following outlines several methods for managing root-knot nematodes:

I. Non‑systemic Soil Treatment

1. Pre-planting treatment

This primarily refers to chemical treatment, such as mixing thiazophos with soil and then evenly applying it followed by rotary tillage. This method can effectively target and control root-knot nematodes, yielding good results; however, with repeated applications, the nematodes’ resistance to the pesticide gradually increases, necessitating a year‑by‑year rise in application rates.

2. Treatment during the reproductive period

Choose formulations such as thiazophos‑water‑soluble solution and abamectin, and apply them via flood irrigation, drip irrigation, or root drenching, adjusting the timing according to the season and the specific growth stage of the crop. Apply in small, frequent doses to achieve minimal or no pest incidence throughout the entire growing cycle.

II. Non-selective Soil Treatment

1. Physical Soil Treatment Methods

Physical treatment methods primarily involve using high-temperature approaches, such as hot water, fire, and solar energy, to eliminate root-knot nematodes in the soil.

1.1 High-Temperature Greenhouse Fumigation

Utilize the high temperatures of the dog days of summer to carry out soil treatment in a plastic greenhouse. Prior to this treatment, till the soil, evenly distribute farmyard manure or straw, and maintain an appropriate soil moisture level. After sealing the greenhouse with plastic film, close the structure and allow the elevated temperatures to help control root-knot nematodes, while also promoting the decomposition and maturation of farmyard manure, straw, and other organic materials.

However, this method has several drawbacks, including uneven temperature distribution, slow heating, long treatment times, and disruption of the soil’s microbial ecosystem. It is therefore more suitable for regions with extended fallow periods between two cropping cycles, such as areas that grow only a single strawberry crop per year.

1.2 Calcium cyanamide

After evenly applying calcium cyanamide together with crop residues or farmyard manure, perform rotary tillage and form raised beds with furrows, maintaining adequate soil moisture. The high temperatures generated by the decomposition of calcium cyanamide and the decomposition of straw and other organic materials effectively kill root-knot nematodes.

2. Chemical Treatment

This primarily refers to a method of controlling root-knot nematode disease by applying chemical agents such as methyl bromide, metam sodium, chloropicrin, and dazomet, which either induce specific chemical reactions or directly kill the nematodes in the soil.

2.1 Methyl bromide

Methyl bromide is used to control root-knot nematodes in the soil, and crops grown in disinfected soils can experience substantial yield increases; however, it has been banned due to its ozone-depleting effects.

2.2 Chloropicrin

Chloropicrin fumigation is a highly effective soil disinfection technique; however, it demands specialized expertise and equipment, requires approval from the local public security bureau, and can only be applied after proper registration.

2.3. Methyl Bromide

The substances contained in methyl bromide granules undergo a series of chemical reactions in the soil, releasing methyl isothiocyanate—a compound with insecticidal activity—to control root-knot nematodes. This method is highly effective and environmentally friendly; however, it places stringent demands on soil moisture, application uniformity, and tillage depth. Improper handling can lead to uneven disinfection or incomplete release of the active ingredient, resulting in seedling damage.

III. Agricultural Practices

Root-knot nematodes must be prevented at the source by selecting highly resistant varieties, using soil‑free or substrate‑based seedling production, and subjecting agricultural machinery to appropriate disinfection before shared use; grafting is also an effective integrated pest management strategy.

IV. Our Company’s Products

Biological control is currently one of the most effective approaches for managing root-knot nematodes. Nongda Fertilizer has recently launched a multifunctional composite microbial agent that combines four key benefits: nematode control, resistance to continuous cropping, nutrient activation, and quality enhancement. This product effectively kills root-knot nematodes while inhibiting the reproduction and infection of pathogenic fungi, thereby reducing soil-borne diseases and delivering outstanding performance in resisting continuous cropping and promoting root development.

Nongda Fertilizer Industry adheres to the principle of controlling pests with beneficial microorganisms, effectively managing nematodes while preserving the soil’s native ecological balance. After colonizing the soil, Bacillus subtilis forms a bio‑protective barrier around the root system, safeguarding crop roots from root‑knot nematode damage. Moreover, its metabolic byproducts efficiently inhibit the proliferation and pathogenicity of soilborne pathogens such as Fusarium, protecting root wounds caused by practices like intertillage from infection by soil‑borne diseases.