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Despite its considerable length (some species up to 2 mm), this threadlike, transparent worm cannot be seen with the naked eye. Roots, stems, leaves and flowers are affected.
Infection occurs with planting material. Affected leaf or baby can be purchased. The danger is represented by any soil-soil purchased in the store, garden soil. Less chance of infection through forest land.
By removing a diseased leaf or stepson on the affected plant, and then touching a healthy plant with these hands, you can infect it with nematodes. Parasites penetrate into plant tissue through stomata or wounds.
It is almost impossible to cure a diseased plant or disinfect the soil!
An adult nematode lays the larvae inside itself, a cyst is formed, with a very stable protective shell. It will be stored for many years in unfavorable conditions for it, in the absence of moisture, when frozen, even when heated to 100 degrees. Poisons, even the strongest ones, do not destroy the cyst either, but only adults kill. Such poisons cannot be used in indoor conditions, they are dangerous both for the plant itself and for humans.
Signs of a nematode
1. The leaf does not give children for a suspiciously long time. There may be other reasons for this, but this should be alarming. If babies do hatch, they grow very poorly. If you carefully examine the root system of the leaf, you can find swelling-galls there. Children, leaf, earth, dishes - everything must be destroyed and your hands washed.
2. If a young plant is affected by a nematode, then this is expressed in the following:
- the stem stretches and thickens;
- growth slows down or stops altogether;
- even a very young rosette has a huge number of tiny stepchildren in the leaf axils, but they hardly grow;
- leaf petioles and peduncles are shortened, the uppermost leaves are practically devoid of petioles;
- the rosette is squat, the center of the rosette often does not rise, but rather below the extreme leaves;
- a large number of tops are molded one on top of the other;
- leaf blades acquire a dark green color, become hard as if leathery, in the center the leaves are disproportionately small, elongated, sometimes as if pointed towards the end, convex, the edges are bent inward, sometimes the tips of the leaf are as if “spiky”;
- on the petioles, veins of the leaf there may be swellings, growths, leaf deformation, yellowing, then dying off;
- the violet is easily susceptible to disease;
- flowers do not form or are ugly, asymmetrical, rigid, small;
- leaf wilting, despite optimal watering - nematodes feed on plant sap, nutrients are spent on the formation of galls, in addition, vascular clogging occurs, all this complicates sap flow and nutrition, leaves lose turgor;
- the roots of violets have a characteristic appearance - in a healthy Saintpaulia, the roots are fibrous, delicate, thin, diverge in all directions, like the hairs of a brush; no "carrot" or celery root thickening should appear.
When affected by nematodes, the resulting swellings on the roots merge into warty growths 2-3 cm in size - these are the so-called galls, in which the larvae grow and turn into sexually mature individuals. The number of larvae there is appallingly huge. On the roots, there should also be no nodules, balls, similar to beads. The color of healthy roots is light brown, yellowish, very young root tips are white. When galls appear on the root system, some of the roots die off, they become brownish, black.
All this should be taken into account when you bought Saintpaulia and after quarantine for a period of 2-3 weeks are going to transplant it into a new pot.
Control and prevention measures for nematodes
- Adding the preparation "Fitoverm" to the substrate in the form of a powder (the active ingredient is aversectin) - the substance does not kill the nematodes, but causes them to disorientate, the pest dies from exhaustion without having time to find the root, and penetrates into it. You can not make phytoverm with watering or spraying.
- You can try to add nematicide or dosamet (tiazone) to the soil before planting the plants.
- Use drugs that help to strengthen the plant's immunity, increase the plant's resistance to adverse conditions.
- Use drugs related to chitosans, which stimulate the development of chitinoparasitizing microorganisms in the soil. Presumably, the earth from under the flowers of marigolds contains such microflora, it has been noticed that nematodes are not activated in it. You can water the violets with the infusion of these flowers or add dried and ground marigold flowers to the soil.
- Maintain soil acidity no more than 6.5 pH. Nematodes do not like an acidic environment, they do not tolerate peat well, so it is advisable to add it when compiling an earthen substrate. So that the soil in the pot does not alkalize, you can water with water infused with peat.
- Wash hands after handling each individual plant of concern.
- Do not grow babies in a common bowl, it is advisable to plant them after separation from the mother sheet in a separate container.
- It is better to keep the pots with violets on separate trays, which must be rinsed very thoroughly from time to time. Water flowing from an infected plant is infectious.
- To create the most favorable conditions for violets, to prevent excess moisture, which contributes to the rapid development of nematodes. Provide the necessary batteries. Timely feeding with microelements reduces the activity of nematodes, a similar effect is exerted by the introduction of vermicompost, therefore “Terra Vita” soil based on vermicompost is good for preparing a substrate for violets.
- When buying violets, it is advisable that the leaf be cut right in front of your eyes from a healthy-looking plant. Otherwise, the leaf must be rooted in a separate container on a separate windowsill. Leave the leaf petioles at a minimum of 1.5-2 cm. There should be no ulceration, swelling or deformation on the petiole and leaf.
- When seating children, carefully examine the roots for the presence of the smallest balls and nodules. During transshipment and transplantation, if the earthen feed is destroyed, dead root areas are visible. In a healthy plant, the earthen ball does not fall apart if it is removed from the pot, and the white tip of the roots is visible over its entire surface.
- If you find one of the signs of nematode infestation, look for other signs. They can be different depending on the type of nematode. If the plant is severely damaged, it is better to get rid of it.
- When using used pots, in order to prevent them, they must be carefully treated with some kind of aggressive liquid to remove congestion in the sewage system, applying it with a brush so as not to damage your hands. Cover the pots with plastic wrap so that the liquid does not dry out, and rinse thoroughly after 15-20 minutes.
Caring for sick violets
If a rare variety of violets turned out to be affected and you want to preserve it at all costs, then you can suggest the following measures:
- find an intact leaf, cut off most of the petiole and try to root it
- if the tip is not damaged, try to cut it off and re-root
- create ideal conditions for the affected plant, change the soil by removing the affected roots, taking preventive measures
The main thing is to try to prevent the spread of the invasion to healthy plants. Flying sucking insects can transmit the infection.
The author of the article is T.A. Rusinova
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