Nematode: signs, treatment and prevention

Finally, in our bestiary we have reached a model organism that moves and is visible to the naked eye! The millimeter nematode Caenorhabditis elegans is a real gift to scientists from nature: it is unpretentious, transparent, and drives progress both in fundamental and in the newest and most fashionable areas of biology. She has made many famous researchers fall in love with her, and we hope that our readers will like her too!

Description of the pest

Herbivorous nematodes have a small thread-like and rounded body up to 2 mm long , narrowed at both ends. Due to the small size of the pest, it is difficult to notice in the early stages.

The color of nematodes can be white or light yellow. The body is covered with a ringed cuticle, under which there are longitudinal muscles. Special muscles ensure the functioning of the reproductive and digestive organs.

The pest has a developed nervous, digestive, excretory system, and reproductive organs, but lacks blood supply and respiration. The digestive system is continuous - it begins with the oral cavity, which has a complex structure, passes into the esophagus, then into the midgut and ends at the posterior end of the body.

All herbivorous nematodes have a movable spine in their mouth - a piercing stylet organ. Worms use it to pierce plant cells and suck out the juices. Enzymes, amino acids, urea and other substances are released into the tissue through the thorn. They block the functioning of all organs in the plant.

The nervous system consists of a nerve ring located near the pharynx and longitudinal nerves. Thanks to the setae on the body, worms can touch; amphid receptors are responsible for the sense of smell.

Herbivorous nematodes are heterosexual , females are larger in size than males. They lay eggs from which larvae emerge. Before adulthood, there are 4 stages of development, accompanied by molting. Depending on the species and living conditions, the duration of each larval stage lasts 2–12 days.

The optimal temperature for the appearance of larvae is 15-16°C, for further development 18–24°C. 40 days after the onset of sexual maturity, females can lay eggs.

Whipworm

Human whipworm is a type of helminth that causes the parasitic disease trichuriasis, which is considered quite common. Typically, the whipworm lives in the thin lower and wide upper intestines.

The whipworm can exist exclusively in the human body, while it does not change hosts, and the development process occurs without migration. In order for the helminth to develop further, it needs to come out in its eggs with human feces. Further development of whipworm depends on soil temperature and humidity levels. If there is an optimal temperature, after just three weeks, whipworm eggs are ready for further reproduction in the soil.

Infection with whipworm in humans, as in the vast majority of cases of helminth infection, occurs through unwashed vegetables, fruits and berries. And in some cases, drinking water can cause infection.

The parasite can remain in the intestines for quite a long time, and the resource for its survival is human blood. The parasite does not feed on anything other than blood, so the treatment process for whipworm presents some difficulties. The parasite digs into the intestinal wall with its anterior end, thereby causing inflammation and disrupting the integrity of the intestine. Poisoning of the human body occurs directly related to the active activity of the parasite.

Signs of its presence may include pain in the head, fatigue, drowsiness and irritability. Due to disruption of the functioning of the intestines, abdominal pain appears, and convulsions are possible in the future. Since the parasite relies on blood to survive, anemia may occur over time. Dysbacteriosis develops. With mass infection, inflammatory processes appear in the appendix.

Types of nematodes

Different types of nematodes specialize in damaging roots, stems, leaves, buds and flowers. Based on this, a species classification of plant-parasitic nematodes .

Leaf nematodes

Motile colorless worms up to 1 mm long. Distributed everywhere. But in open ground they are more harmful in wet years in the central zone, in the northwestern region and in the south of Russia. They parasitize on the above-ground parts of plants: outside or inside leaves, buds or buds. The soil is a temporary habitat for them. They move along a thin film of water on the surface of the plant and penetrate inside through small lesions and stomata.

One generation develops within 10–11 days; 20 or more generations can appear in a year. The pest overwinters only in above-ground parts, most often in young shoots. It reproduces in leaf axils, buds and in mesophyll microorganisms on the surface of plants.

Leaf nematodes attack strawberries and ornamental plants: chrysanthemums, asters, begonias, dahlias, phlox, primrose, iris, gerberas, pelargonium, peonies, violets, lilies, cyclamen and others.

Stem nematodes

Transparent thread-like worms up to 1.7 mm in length. In our country, this species is found everywhere on heavy soils and is active in regions with a temperate climate. The life cycle of one generation lasts 3–5 weeks, the favorable temperature for the development of the pest is 5–34°C. During one season, 4–6 generations appear. The females of this nematode are fertile, laying from 200 to 400 eggs. The pest overwinters in rhizomes, roots and stem bases.

Stem nematodes live on 500 species of vegetable, berry and flower and ornamental crops. The above-ground parts are damaged: stems, leaves, flowers, as well as seeds, rhizomes and bulbs. It hardly damages the roots. They penetrate only into living tissues through stomata, where they live and reproduce.

Stem nematodes prefer to parasitize one host plant without moving to other species. from stem nematodes : onions, potatoes, tomatoes, peppers, eggplants, carrots, pumpkins (cucumber, watermelon, pumpkin), ornamental plants: tulips, phlox, begonias, hyacinths, carnations .

Root nematodes

Colorless round worms, 1.3–1.5 mm long, living in the soil near the roots of plants. This type of nematode is divided into 3 groups:

Root-knot nematodes

The saliva secreted by the pest causes the formation of round or elongated thickenings on the roots - galls 3-5 mm in size . Inside the galls, nematodes feed on plant sap and reproduce annually from 1 to 13 times. Females lay up to 2000 eggs in special egg sacs over the course of 2–3 months. Males do not always take part in reproduction. The emerging larvae migrate, find the roots of the new host plant and begin to feed. They reach sexual maturity in 3–4 weeks.

Dangerous for more than 400 plant species - vegetables and ornamental crops. They are sensitive to low temperatures and are more often found indoors. Celery, lettuce, carrots, tomatoes, eggplant, peppers, strawberries, melons and legumes are severely . Ornamental plants include roses, clematis, ficus, begonias .

Free-living nematodes

Common on coarse-porous and sandy soils. Thanks to good aeration, the pest actively moves in the ground. Lettuce, celery and carrots are often affected by this pest.

Nematodes with free cyst formation

The spread of the pest occurs with the help of cysts formed on the roots - dark brown capsules the size of a poppy seed . Dead females with viable eggs and larvae turn into cysts. Each cyst contains up to 700 eggs and larvae.

The larvae do not die in winter and leave their shelter with the arrival of warm weather, but can remain in this preserved state for up to 10 years. Representatives of this group include golden potato nematode on nightshade crops, beet nematode , which damages cruciferous plants and beets.

Pests deplete plants and contribute to the spread of fungal, viral and bacterial diseases, the pathogens of which penetrate through damaged roots. With severe infection of roots, losses among vegetable crops reach 25–80% after 3–4 months.

Causes

The etiogenesis of nematodes in humans and animals is based on objects, soil, food, water contaminated with mature (invasive) eggs or larvae, which are ingested orally, that is, through the nutritional route. In addition, infection from vectors, for example from blood-sucking insects, from person to person is possible, for example, the spread of enterobiasis, especially in children's groups. For hookworms and strongylids , percutaneous penetration is also possible.

Signs of plant infection by nematode

For successful reproduction and development of nematodes, heat and humidity are required. Rainy summer weather, acidic and sandy soils contribute to the spread of pests . In dry soil and when the temperature drops, they fall into suspended animation, stop reproducing or die.

Nematode on strawberry

Yellow-brown, reddish spots appear between the veins on strawberry leaves. The petioles also change color: they turn red and lose their pubescence. In places of darkening, the leaves become thinner, turn brown, dry out or rot.

Infected bushes lag behind in growth and development. The whiskers are shortened, the rosettes are deformed, and their central part dies over time.

Nematode on potatoes

Worms penetrate the roots, suck the juices out of the plant, taking away the strength for growth and development. Such bushes have only 1–3 stems, the leaves are small - during the day they look lethargic, lose their green color and turn yellow, and then dry out. The root system weakens, tubers do not set at all, or there are few of them and most of them are small.

Nematode on onion

Plants into which nematodes have invaded develop thickened and curved feathers, which turn yellow and droop over time. Inside, the bulb becomes soft and loose, and begins to rot from the inside.

Nematode on beets

On affected plants, the leaves change color - they turn brown and become limp. The beets are stunted in growth, and signs of rot are visible on the root crops removed from the ground. If they are not damaged, then most often they are small in size and have many adventitious roots. In winter, such a crop is poorly stored.

Nematode on chrysanthemums

Nematodes damage many ornamental plants, but most often among garden flowers they settle on chrysanthemums. First, light yellow spots appear on the leaves. They turn brown and the leaves die. The shoots are shortened, and some appear thickened and swollen.

Flowers on such chrysanthemums do not form or become smaller and deformed. The chrysanthemum nematode also damages other garden flowers: asters, delphiniums, zinnias, phlox, begonias .

During pregnancy

Nematodosis during pregnancy is an extremely dangerous condition, both for the woman and for the unborn child, because invasion can occur through the placenta and even milk.

It is very important not to confuse the signs of helminthiasis and early toxicosis. Chronic nausea with vomiting, dizziness, fainting, and heart pain may be a cause for alarm. Most likely, these are signs of ascariasis or enterobiasis . They not only worsen a woman’s well-being, but also have a toxic effect on the fetus and can cause asphyxia and premature labor.

Peperazine is considered the safest drug for pregnant women , but an additional laxative can be prescribed to more quickly evacuate worms from the intestines.

Nematode control agents

Chemical and biological drugs

Heterophos

The soil insecticide is produced in 2 forms: granules and suspension. Consumption of the drug in dry form is 4-8 g per 1 square meter. m. To soak the roots of seedlings before planting, prepare a solution of 15 g of the drug and 10 liters of water. The toxic effect on the pest lasts 1.5–2 months.

Phosfamide

Insecticide of contact and systemic action. To spray plants and soil against nematodes, use a 0.02% insecticide solution. Work is carried out in dry and windless weather.

Nematorin

Granular insecticide against all types of nematodes. Affects the pest's breathing, causing paralysis and death within a few hours after application. The drug is applied before and after planting plants into the soil to a depth of 10–15 cm. The consumption rate of the product is 3 g per 1 sq. m. m.

Akarin P

An effective remedy in powder form for root-knot nematodes. The decomposition products of the drug deprive the pest of the ability to find the roots of the host plant and the nematodes die within 14–20 days. The drug retains its properties for 2–4 months, is not washed out of the soil by water and increases resistance to disease.

Akarin is applied into the ground to a depth of 20–25 cm 1–3 days before planting or spot-on when replacing an infected plant with a new one. When applied in rows, the consumption of the drug is 200 g per 1 sq. m.

Nematophagin

Liquid biological product against nematodes based on a predatory fungus. Ring-shaped trapping nets develop on the mushroom mycelium. By touching them, the pest sticks and gets caught in the net. Within 24 hours, the fungus consumes the nematode. Developing in the soil or on plant debris, predatory fungi release metabolic products that are toxic to worms.

The drug is applied to the soil before sowing (100–300 ml per 10 liters of water), planting plants in the ground (5–10 ml in each hole or 1–3 liters per 1 sq.m.), the soil around the affected plants is treated (20–30 ml per 1 plant to a depth of 15–20 cm).

Fitoverm P

To disinfect the soil, 1–3 days before planting, the powder is evenly scattered over the surface of the ground and mixed to a depth of 10–15 cm or 18 g in each hole if it is necessary to replace a diseased plant. The protective effect lasts up to 2 months.

Traditional methods

Herbal decoctions and infusions cannot cope with the nematode . Non-chemical methods will repel the pest by planting phytoncidal plants in the rows: calendula, marigolds, mustard lettuce .

Root nematodes are caught using baits . The juice is squeezed out of potato sprouts and introduced into the soil. Since the pest has a good sense of smell, the smell serves as a signal for the cyst to open, but not finding food, the larvae die. This procedure is carried out 1–1.5 weeks before planting.

The number of nematodes in the surface layer can be reduced by thermal soil treatment . Before planting, water the soil with boiling water, saturating it to a depth of at least 15 cm. This method is more suitable for greenhouses and greenhouses.

Diet for nematodes

Diet for anemia

• Efficacy: no data
• Time frame: 3 months
• Cost of products: 2700-3200 rubles. in Week

Most nematodes significantly poison and weaken the human body, so the diet if such an unpleasant illness is detected should be aimed at improving health and restoring strength, while fully providing fats and carbohydrates in proteins. If someone in your family has helminthiasis, then in addition to worming you should:

• eat healthy food - do not fry it, do not eat spicy, smoked, etc.;
• give up street food, alcohol, caffeine and white sugar;
• calculate and consume the daily intake of dietary meat, vegetables and fruits, taking into account the patient’s body weight and physical activity;
• introduce porridge, whole grain baked goods or pasta, herbs, onions and garlic, high-quality vegetable oil, seafood, dairy products, dried fruits, nuts, seeds and other healthy ingredients into your diet.

Prevention

Effective preventive measures against the pest are:

• Maintaining crop rotation.
• Growing varieties and hybrids resistant to nematode damage.
• Selection of healthy planting material.
• Before planting, bulbs and tubers are heated for 15 minutes at a temperature of about 45–50°C.
• Reducing soil acidity (regular liming) reduces the number of pests.
• Plantings are regularly weeded and thinned.
• Post-harvest plant residues are removed from the beds and the remaining damaged plants are destroyed along with the soil layer.
• Sowing cereals in late summer - early autumn cleanses the soil well and increases fertility. The area cleared of weeds is loosened and sown with grain crops to a depth of 2–3 cm. Before frost they will germinate and the soil along with the green sprouts will be dug up and the entire layer of soil will be turned over.

Today, when a pest appears, there is no need to abandon the site and wait for years for the soil to be cleared of the nematode. Modern drugs successfully fight them, and preventive measures will prolong the effect for a long time.

Find out more about the nematode and how to fight it from the video.

Symptoms of nematode

Single parasites may not cause symptoms for a long time and the disease is mild. But most often, various types of nematodes cause disturbances in organ systems such as digestive, nervous, reproductive, etc., but the most common symptoms are:

• indigestion;
• pain in the lower abdomen;
• loss of appetite;
• fever;
• weight loss;
• itching in the anus;
• decreased performance;
• headache;
• restless sleep;
• dizziness;
• nausea with vomiting;
• weakness and deterioration in health;
• tachycardia and decreased blood pressure;
• allergic reactions and even anaphylactic shock .

Specific symptoms of necatoriasis

Necatoriasis caused by Necator americanus and hookworm (caused by Ancylostoma duodenale) are called hookworm disease and are characterized by significant disturbances of the circulatory system. Since worms of these species are hematophytes that feed on blood, they injure blood vessels with their cuticular teeth and secrete an anticoagulant, which causes ulceration, severe bleeding and, as a result, significant blood loss . Patients experience symptoms such as:

• chronic iron deficiency anemia ;
• dyspnea;
• lethargy;
• developmental delay in children;
• edema;
• diarrhea mixed with mucus and blood;
• representatives of the black race may develop depigmentation due to iron deficiency.

Notes[ | ]

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2. ↑ 1 2 3 4 Hodda, Mike.
   Phylum Nematoda Cobb 1932 (English) // Zootaxa. - 2011. - No. 3148. - P. 63-95.
3. ↑ 1 2 Lambshead PJD
   Recent developments in marine benthic biodiversity research // Oceanis.
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4. Nematoda from the terrestrial deep subsurface of South Africa: Nature: Nature Publishing Group (unspecified)
   . Access date: June 13, 2011. Archived September 20, 2011.
5. ↑ 1234
   Collier's Encyclopedia, 2000.
6. ↑ 12
   Nematodes // Biology. Modern illustrated encyclopedia / Ch. ed. A. P. Gorkin. - M.: Rosman, 2006. - 560 p. — (Modern illustrated encyclopedia). — ISBN 5-353-02413-3.
7. Poinar GO et al.
   Earliest fossil nematode (Mermitidae) in Cretaceous Lebanese amber // Fundam. appl. Nemawl. - 1994. - No. 475-477.
8. Gubanov N. M.
   Giant nematode from the placenta of cetaceans -
   Placentonema gigantissima
   nov. gen., nov. sp // Reports of the USSR Academy of Sciences. - 1951. - T. 77, No. 6. - P. 1123-1125. Archived from the original on March 3, 2021.
9. ↑ 123
   Biological encyclopedic dictionary, 1986.
10. Nematodes gain experience as they mature - Neuroscience (undefined)
    .
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    . chrdk.ru. Access date: January 10, 2021.
11. Smith H.
    Sperm motility and MSP // WormBook. - 2006. - doi:10.1895/wormbook.1.68.1.
12. Yushin V.V., Malakhov V.V.
    Origin of nematode spermatozoa: progenesis at the cellular level // Biology of the sea. - 2014. - No. 40. - P. 83–94.
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    BG Chitwood, 1957, Phylum name.
    (undefined)
    . Access date: February 22, 2011. Archived November 29, 2012.
14. ↑ 123
    Malakhov, 1986.
15. Key to parasitic nematodes. T. 1. Spirurates and filariates / Ed. K.I. Scriabin. - M.-L.: Publishing House of the USSR Academy of Sciences, 1949. - 520 p. — P. 243.
16. Zoology of invertebrates. T. 1: From protozoa to mollusks and arthropods / Ed. V. Westheide and R. Rieger. - M.: KMK, 2008. - iv + 512 p. — ISBN 978-5-87317-491-1.
17. Margulis L., Chapman MJ.
    Kingdoms & Domains: An Illustrated Guide to the Phyla of Life on Earth. 4th ed. - Amsterdam: Academic Press, 2009. - 659 p. — ISBN 978-0-12-373621-5. - P. 274.
18. Stichosomida (English). ucdavis.edu. Date accessed: August 7, 2017.
19. ↑ 1 2 Nematodes
    - article from the Great Soviet Encyclopedia.
20. Nematodes // 1. Small medical encyclopedia. — Medical encyclopedia. 1991–96 2. First aid. — Great Russian Encyclopedia. 1994 3. Encyclopedic Dictionary of Medical Terms. — Soviet encyclopedia. - 1982-1984 (Russian). - M.
21. Nematode plant diseases
    - article from the Great Soviet Encyclopedia. Sveshnikova N. M..
22. ↑ 1 2 Sharova I. Kh.
    Zoology of invertebrates.