What are nematodes and how to deal with a pest? Plant rescue

One of the most dangerous plant pests are nematodes. These are microscopic worms attacking the root, stem and leaves. For their nutrition, they use plant juice, saturated with useful substances; therefore, infection leads to depletion of the victim and even its death, as well as to a decrease in the quality and quantity of the crop.

What are nematodes?

In a broad sense, nematodes are all roundworms. About 24,000 of their species have been scientifically described, but biologists are sure: the figure is far from final. Some scholars have suggested that these creatures are actually represented by a million species. Roundworms take second place (after insects) in species diversity in the entire animal kingdom.
Roundworms are parasitic, living in the body of protozoa, plants and animals and feeding on their resources, or free-living nematodes.

All nematodes are small worms: only 1–2 mm, which makes them practically elusive to the naked eye of a person. The males are slightly longer than the females. The torso in the section is an even circle, for which these microscopic creatures got their second name. Only towards the ends of both sides are the nematodes slightly narrowing. The color of the species varies from pure white to cream, often with a yellowish, almost golden hue.
A feature of nematodes is the special structure of the body: it has a bag of muscles and skin. From above, it is protected by an elastic cuticle of either a smooth or annular structure, wrapped in an epithelium. All this makes the worm extremely resistant to adverse environmental influences and chemicals, which complicates the fight against the pest.

The movement of nematodes is carried out thanks to the longitudinal muscles, passing immediately under the skin. The head of the worm is very small. On it are lips, small eyes and special bristles that are responsible for touch.

Reproduction in nematodes is bisexual. From white eggs (round or oval), larvae with a transparent end of the body appear. Many nematodes are plant parasites, and it is in this role that they are known to vegetable growers, gardeners and gardeners. Depending on the species, they affect different parts of the plantings and give preference to special crops in nutrition.

Types of Nematodes

There are a huge number of nematodes that harm human plantings. The most significant of these are three. They differ from each other in that they affect different parts of plants.

Root

Roundworms up to 2 mm in length. This species is also called gall, because in the places of manifestation of the root galls are formed on it - seals and tubercles. At first they are yellow, but eventually become brownish brown.

Gauls disrupt the movement of nutrients in the root system, so it begins to function improperly.

Favorable conditions for the life of root nematodes are:

• temperature from 18 ° C to 24 ° C;
• soil moisture 40-60%.

In such conditions, the pest actively eats and multiplies rapidly. The full life cycle of the root nematode takes about a month. Its duration depends on environmental conditions: if they are suitable, then up to 6 generations appear per year.

Sometimes bulbs are formed on the roots, in which nutrients and moisture accumulate. This is a normal and useful process. Such neoplasms can be distinguished from traces of the activity of nematodes by color and shape: they are white and oval.

The spread of root nematodes occurs primarily through the ground. Also put the pest in the ground possible with planting material, pots, garden tools.

Leafy

Leaf nematodes are very small: their body length is 1 cm. They are characterized by a high speed of movement and parasitism in the leaf plates of plants. The most vulnerable to infection with this species are strawberries and chrysanthemums. The danger of leaf nematodes lies not only in the nutrition of the plant's vital juices, but also in the fact that they carry viral diseases. Especially often the leaf nematode harms strawberries and chrysanthemums.

They spend almost their entire life in a sheet, where they penetrate through mechanical damage to its surface. Only occasionally do these pests descend to the ground, which serves as temporary shelter in case of emergency. Worms usually survive winter in dry leaves

Stem

The length of stem nematodes also does not exceed 1 mm. Most often, they parasitize in the stem of a plant, but can move into leaves and flowers. Infection occurs through the root system, into which the worm larvae penetrate. This species usually affects vegetables: tomatoes and cucumbers, as well as onions and garlic.

Nematode Harm

Nematodes for plants are very dangerous, because these worms feed on their juice. As a result of planting, they begin to grow more slowly and literally wither away before our eyes, which ultimately negatively affects the crop. With mass infection, the plants completely stop developing and eventually die.

Plant diseases caused by this worm are called nematode. They are subject to grassy species, and shrubs, and trees. Both wild and cultivated species are affected, so it is very difficult to escape from the parasite.

Another aspect of the nematode harmfulness is related to damage to the plant integrity by these worms. The holes and passages made by them are an excellent way for the penetration of pathogenic microorganisms, which also provoke the appearance of diseases. Thus, landings receive a double blow, the consequences of which are always negative. The degree of damage caused by nematodes depends on their number and environmental conditions: in a favorable environment, they do much more harm than, for example, in the cold spring. But, unfortunately, the climate of the middle zone can be called ideal for the life of the pest.

Signs of infection

Since different types of nematodes infect certain parts of plants, the signs of infection differ depending on what was affected by the pest: root, stem or leaf.

Root

The activity of the root nematode leads to:

1. The beginning of a strong branching of the root system and, at the same time, to decay and death of small roots:
2. The formation of galls of various shapes and "beaks" - acute swelling;
3. To ulcers on the root surface, eventually leading to their death. Through them penetrate bacteria, viruses and fungi, which further exacerbates the situation.

External changes of the green part of the plant also occur. At first, the symptoms of infection are similar to signs of moisture and nutrient deficiency. In general, the donor plant of the parasite looks oppressed, grows slowly, and its leaves at the edges twist and dry out.

If you dig a plant, you can see that numerous thin roots, or the so-called root beard, grow above the gall.Unfortunately, you can accurately verify the presence of nematodes only by digging the plant from the ground. In most cases, it is usually not possible to save him: the pest does such severe damage.

Sheet

But traces of the activity of the leaf nematode are clearly visible: dry spots of yellow or brown color with foci of necrosis appear on the leaves. These expressions are arranged in a chaotic manner. At the same time, the leaf begins to fade and taper. Then it becomes very subtle: so that rays of light pass through it. Soon, the leaf begins to completely drill and dry. When losses reach critical proportions, the whole plant dies.

Stem

When infected with a stem nematode, the stem thickens as a spindle. Also observed:

• an increase in petioles of leaves (they swell);
• stunting and the appearance of wrinkles on the leaves of strawberries;
• the appearance of dark and soft spots on potato tubers;
• loosening the bulbs.

All of these types of nematodes emit toxic substances. They, getting into the vessels of plants, lead to the formation of seals. Therefore, plants infected with a nematode have an ugly appearance. In addition to the clumsy shoots and leaves, the green part gradually turns pale, after which it dies.

Ways to fight

If at the site it is found that one or several plants are infected with a nematode, then immediate action is required. Ringworms are highly fertile, so if you do not take measures in time, the scale of the lesion will be colossal.

The best option is to destroy the plant. So you can hope that the nematodes do not have time to move to his neighbor. For this, the plant is dug up and burned. It is also necessary to spill the earth around the hole with hot water. If it is an indoor flower, then it is treated with boiling water and a pot.

It is important to conduct heat treatment of all tools used in the work, and shoes.

In the fight against nematodes, chemical, biological and folk remedies may be useful. Plantations will be saved if the damage is not yet critical. In this case, we can hope that the plants will be able to recover and gain strength again.

Chemicals

The main difficulty in the fight against nematodes is that there are no drugs that can destroy the laying of eggs of worms and larvae. Therefore, one treatment with even the most powerful chemicals will not be enough: 3-4 procedures will be required, repeated as offspring appear (with an interval of 10-14 days).

The pest is destroyed with the help of nematicides - chemicals that are effective against adult annelids. All drugs are divided into 2 types:

1. Means with fumigant properties (carbation, methyl bromide, nemagon, chloropicrin). They poison nematodes by entering microscopic creatures through their respiratory system. With the help of fumigants, root nematodes are destroyed by spilling soil and processing planting material (seedlings, bulbs, seeds, seedlings).
2. Organophosphorus compounds. For example, it is methyl mercaptophos, phosphamide and familiar to many karbofos. Such substances have a contact type of exposure, penetrating the body of the worm through its skin. Phosphorus compounds are effective against leaf and stem nematodes. Such substances are used in dry and calm weather following the instructions and safety precautions.

The exact timing, dosage and recommendations for the introduction of fumigants and organophosphorus compounds are individual for each agent. General rule: toxic substances for plants are applied to the soil 10–40 days before sowing or in autumn; and spraying is carried out at least a month before harvesting. In this case, it will be safe to eat.

Biological

Another type of nematode killing agent is biological. They act slower than chemicals, but are completely safe for plants and crops, humans and animals, because there are no toxic components.

Against root nematodes that affect the plantings of cucumbers and tomatoes in greenhouses, the Basamil KS bio-insecticide, produced in the form of a concentrated suspension, is effective. The active ingredient of “Basamil” is fungi that parasitize on females and eggs of worms, thereby stopping the reproduction of the pest.

The drug is used by spraying a strait of soil with a solution prepared according to the instructions. To destroy the nematode in the greenhouse, 3 soil treatments are needed. You can use the drug before planting, and during the growing season of plants.

Heat treatment of indoor plants

The fact that nematodes live in the soil and feel comfortable at temperatures up to 25 ° C can be used against them. To destroy the pest, the plant is given a hot shower at a temperature of 40 ° C for half an hour. So you can be sure that both eggs and larvae will die. This method is successfully used for seedlings and indoor plants, which after heat treatment must be planted in a safe soil and container.

Folk remedies

The list of folk remedies that help fight nematodes is scarce. This is due to the enviable survivability of the worms. Only a couple of effective methods are known, which, according to gardeners, scare off the parasite or reduce its number.

For example, as practice has shown, the use of Dekaris tablets, which are an anthelmintic, helps. They can be purchased at the pharmacy. To prepare the solution, the tablets are crushed and stirred in water at the rate of 1 tablet per 1 liter. The resulting liquid is watered on the soil and the plants themselves. To notice the result, you will need at least 3-4 treatments carried out with an interval of 10-12 days.

Another option is to plant plants near the beds and greenhouses, the pungent smell of which repels the worm. First of all, we are talking about marigolds (compact varieties) and calendula: its roots secrete substances into the soil that are not tolerated by the nematode, but that stimulate the vital activity of beneficial organisms. Similar, but weaker properties are possessed by coreopsis and rudbeckia.

Preventative measures

So that you do not have to start a fight with a nematode, you can adhere to the rules for preventing worm infection. They are pretty simple:

1. Carefully inspect the planting material, choosing only healthy. We are talking about seedlings, cuttings, seedlings, etc.
2. Affected plants must be destroyed and not used for reproduction.
3. Quarantine new indoor flower purchases.
4. Pay great attention to the quality of the soil for seedlings and domestic plants: even purchased can be infected, not to mention the soil taken from the site. Therefore, it is recommended that the new earth be calcined in the oven: nematodes die at high temperature.
5. Crop rotation must be observed at the site, because pests favor certain species.
6. It is necessary to loosen the soil and remove weeds in a timely manner.
7. A regular inspection of the plantings will help you in time to see the signs of damage and get rid of the nematodes before they hit the neighboring plants.
8. The application of organic and mineral fertilizers will make the plantations stronger, and the risk of nematode diseases will decrease.

Thus, prevention comes down to the proper care of plants and their inspection. These are two fundamentals of protection not only from nematodes, but also from other pests, as well as diseases.

Nematodes are the worst enemies of plants and those who grow them. In the absence of struggle against them, worms completely destroy the plantings, and in the best case, reduce the quality of the crop. But by taking preventive and special measures, you can avoid this or reduce the damage from the activity of nematodes.