A nematicide is a type of

chemical A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...

pesticide Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

used to kill plant-

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

s. Nematicides have tended to be broad-spectrum toxicants possessing high volatility or other properties promoting migration through the soil.

Aldicarb Aldicarb is a carbamate insecticide which is the active substance in the pesticide Temik. It is effective against thrips, aphids, spider mites, lygus, fleahoppers, and leafminers, but is primarily used as a nematicide. Aldicarb is a cholinest ...

(Temik), a

carbamate In organic chemistry, a carbamate is a category of organic compounds with the general Chemical formula, formula and Chemical structure, structure , which are formally Derivative (chemistry), derived from carbamic acid (). The term includes orga ...

insecticide marketed by

Bayer CropScience Bayer AG (English: , commonly pronounced ; ) is a German multinational pharmaceutical and biotechnology company and is one of the largest pharmaceutical companies and biomedical companies in the world. Headquartered in Leverkusen, Bayer's a ...

, is an example of a commonly used commercial nematicide. It is important in

potato The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade famil ...

production, where it has been used for control of soil-borne

nematodes The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (he ...

. Aldicarb is a

cholinesterase The enzyme cholinesterase (EC 3.1.1.8, choline esterase; systematic name acylcholine acylhydrolase) catalyses the hydrolysis of choline-based esters: : an acylcholine + H2O = choline + a carboxylate Several of these serve as neurotransmitte ...

inhibitor, which prevents the breakdown of acetylcholine in the synapse. In case of severe poisoning, the victim dies of respiratory failure. It is no longer authorised for use in the EU and, in August 2010, Bayer CropScience announced that it planned to discontinue aldicarb by 2014. Human health safety and environmental concerns have resulted in the widespread deregistration of several other agronomically important nematicides. Prior to 1985, the persistent

halocarbon Halocarbon compounds are chemical compounds in which one or more carbon atoms are linked by covalent bonds with one or more halogen atoms (fluorine, chlorine, bromine or iodine – ) resulting in the formation of organofluorine compounds, or ...

DBCP 1,2-Dibromo-3-chloropropane (dibromochloropropane), better known as DBCP, is the organic compound with the formula BrCH(CHBr)(CHCl). It is a dense colorless liquid although commercial samples often appear amber or even brown. It is the active ing ...

was a widely used nematicide and soil

fumigant Fumigation is a method of pest control or the removal of harmful microorganisms by completely filling an area with gaseous pesticides, or fumigants, to suffocate or poison the pests within. It is used to control pests in buildings (structural ...

. However, it was banned from use after being linked to sterility among male workers; the

Dow Chemical The Dow Chemical Company is an American multinational corporation headquartered in Midland, Michigan, United States. The company was among the three largest chemical producers in the world in 2021. It is the operating subsidiary of Dow Inc., ...

company was subsequently found liable for more than $600 million in damages. Several natural nematicides are known. An environmentally benign

garlic Garlic (''Allium sativum'') is a species of bulbous flowering plants in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chives, Welsh onion, and Chinese onion. Garlic is native to central and south Asia, str ...

-derived

polysulfide Polysulfides are a class of chemical compounds derived from anionic chains of sulfur atoms. There are two main classes of polysulfides: inorganic and organic. The inorganic polysulfides have the general formula . These anions are the conjugate bas ...

product is approved for use in the European Union (under Annex 1 of 91/414) and the UK as a nematicide. Another common natural nematicide is obtained from

neem cake Neem cake organic manure is the by-product obtained in the process of cold pressing of neem tree fruits and kernels, and the solvent extraction process for neem oil cake. It is a potential source of organic manure under the Bureau of Indian Standa ...

, the residue obtained after cold-pressing the fruit and kernels of the

neem ''Azadirachta indica'', commonly known as neem, margosa, nimtree or Indian lilac, is a tree in the mahogany family Meliaceae. It is one of the two species in the genus '' Azadirachta''. It is native to the Indian subcontinent and to parts of S ...

tree. Known by several names in the world, the tree was first cultivated in

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

in ancient times and is now widely distributed throughout the world. The root exudate of marigold (''

Tagetes ''Tagetes'' () is a genusSoule, J. A. 1996. Infrageneric Systematics of Tagetes. Pgs. 435-443 in Compositae: Systematics, Proceedings of the International Compositae Conference, Kew 1994, Vol. I, Eds. D.J.N. Hind & H.J. Beentje. of 50 species ...

'') is also found to have nematicidal action.

Nematophagous fungi Nematophagous fungi are carnivorous fungi specialized in trapping and digesting nematodes. More than 700 species are known. Species exist that live inside the nematodes from the beginning and others that catch them, mostly with glue traps or in ...

, a type of

carnivorous fungi A carnivorous fungus or predaceous fungus is a fungus that derives some or most of its nutrients from trapping and eating microscopic or other minute animals. More than 200 species have been described, belonging to the phyla Ascomycota, Mucoromyc ...

, can be useful in controlling nematodes, ''

Paecilomyces ''Paecilomyces'' is a genus of fungi. A number of species in this genus are plant pathogens. Several of the entomopathogenic fungi, entomopathogenic species, such as "''Paecilomyces fumosoroseus''" have now been placed in the genus ''Isaria'', ...

'' being one example. Besides chemicals, soil steaming can be used in order to kill nematodes.

Superheated steam Superheated steam is steam at a temperature higher than its vaporization point at the absolute pressure where the temperature is measured. Superheated steam can therefore cool (lose internal energy) by some amount, resulting in a lowering of its ...

is induced into the soil, which causes almost all organic material to deteriorate.

References

{{Pesticides

See also

References