What causes root knot nematodes? Is the harm too big, and how should it be prevented?

It is mainly the improper application of fertilizers that cause pests and diseases. The harm is very large, you should use a plant-specific insecticide, spray evenly on the leaves of the plant, and do not water it during the medication, otherwise it will reduce the efficacy of the drug.

Specifically, there is a strong emphasis on the application of microorganisms; The use of nutrients should be scientific and comprehensive; "Nutrition + stress", which opens the secondary metabolism of plants; Use inputs with caution. Nematodes are very harmful, making crops grow short, slow, abnormal leaf color, small fruit, low yield, and even cause plant death. Control methods, remove nodules, dry or burn.

<> the use of pesticides is not standardized, it will cause the ability of root-knot nematode to increase drug resistance, and bring certain difficulties to the prevention and control, after the use of unrotted farm manure and the discovery of root-knot nematode disease, the amount of pesticides used is insufficient, or the use of inferior pesticides, for the prevention and control of root-knot nematodes overwintering in diseased tissues with adults or eggs, or overwintering in the soil with larvae. Diseased soil and diseased fertilizer are the main diseases. The following year, overwintering larvae or eggs hatch into larvae that invade from the roots, resulting in an initial infestation in the field, followed by a subsequent infestation.

Severe disease occurs in drought years when there is little rain and irrigation is not timely. It is severe in loose soils, weak water retention capacity, well-ventilated sandy loam, sandy soils or poor soils. It is mild in alkaline soils with poor air permeability, strong viscosity and low-lying terrain.

The roots should be burned after drying; 3.It can be eradicated by means of fire, soil exposure and high-temperature simmering in the summer season. Root-knot nematodes, prevention before colonization, use avermectin or thiazolphosphine granules ditch application or hole application, melon leafy vegetables pay attention to thiazophosphine.

New chemical agents are often used for a long time and do not have any effect on large root-knot nematodes, resulting in a state of paralysis and dormancy, and when the time is right, they will come out to reproduce. The roots of the damaged crops often form nodules, which hinder the normal nutrient absorption of the crops, causing the leaves to kill the insecticidal eggs. Two biologics are recommended here, one is Penicillium lavender, and the other is bioclochlorim.

Penicillium lavender is a fungal microorganism, which inactivates pathogenic microorganisms bound to root-knot nematodes, but has a short survival time and is unstable. When growing seedlings, we should choose the soil that does not have root-knot nematode disease for seedlings-raising, and the soil with root-knot nematode disease should be disinfected before raising seedlings, and we must ensure that the seedlings are not infected.

Sunlight disinfection, after the fruit is harvested, sunlight can be disinfected, in the hot summer season, ploughing and watering after covering the film, drying for 5-7 days.

The soil disinfection line is warped, which obviously controls and alleviates diseases, so that the root parts of crops play a good role in comprehensive disease prevention and disease resistance.

If this problem is more serious in a piece of land, you can fallow for a period of time, if it is a greenhouse, sprinkle quicklime, and then irrigate it, so that it will produce high temperatures, and then cover it with mulch film to kill pests in the soil. If it is summer, ploughing and then covering the film, using sunlight can also be a good way to kill pests.

This bug will only survive in a dirty environment, as long as the fields are kept clean, they will never breed.

Crop rotation of vegetable fields with root-knot nematodes, and try to implement crop rotation, especially rice and onion, garlic and other crop rotation, the effect of controlling root-knot nematodes is better. Do not rotate with nematode-prone vegetables such as eggplant, tomato, celery, lettuce, carrots and other vegetables.

1.Agricultural control.

1) Select vegetable varieties with high resistance to nematode disease, at present, the disease-resistant varieties of tomato include Romana, Monita-resistant, FA-1420, Millennium, Laihong No. 1, etc. The disease-resistant varieties of loofah include five-leaf fragrant loofah, Jiangshu No. 1 loofah, etc.

2) Implement crop rotation, a nematode is generally harmful in the same family, the same genus or adjacent family, and adjacent genera, so the distal family and genus interval method can be used for 2 3 years interval rotation to reduce the population density of root-knot nematodes in the soil.

Plots where vegetables are often planted can be rotated with gramineous crops such as wheat and corn or with more disease-resistant bell peppers, onions, garlic, leeks, etc.

3) Rational fertilization, aPotash fertilizer can improve plant toughness and prevent the infiltration of root-knot nematodes. b.

The application of well-decomposed chicken manure can significantly reduce the number of root knots and promote the growth of vegetables. c.After the application of tea tree mushroom residue, the initial infection of root-knot nematodes could be delayed, and the epidemic rate of the disease could be effectively reduced.

d.Highly concentrated products such as seaweed extract and humic acid can help soil remediation and improve crop disease resistance.

4) Greenhouse cleaning, after harvesting, thoroughly remove diseased roots, stump roots and weeds in the field, and turn over the soil, which can reduce the amount of insects in the soil.

5) Cultivate disease-free and strong seedlings, raise seedlings with fertile field soil that has not been planted with vegetables, or buy vegetable seedlings with nutrient bowls, and treat them with pesticides when planting.

2.Physical control.

1) Soil removal and frozen soil, serious damage to the old shed for many years, can be moved out of the shed after the vegetable seedlings are pulled 0 20cm of the topsoil out of the shed, centralized treatment. If the soil of the shed is exposed for more than 30 days in the severe winter season, some of the overwintering eggs will be frozen.

2) Solar soil disinfection, choose the hottest month, cover the moist soil with plastic film for more than 4 weeks, which can effectively kill or reduce pests in the soil.

3) Soil hot water treatment, hot water disinfection of soil is a measure to prevent and control root-knot nematodes for the development of pollution-free and pesticide residue-free vegetables. It not only kills nematodes, but also makes the soil moisture content reach a supersaturated state, which is conducive to the growth of crop roots.

4) Lime nitrogen disinfection, lime nitrogen, also known as black fertilizer or black fertilizer, belongs to strong alkaline fertilizer. After being applied to the soil, it reacts with water and eventually decomposes into ammonia, which is directly absorbed by plants. During planting, 500 times of avermectin was added to the treatment, which had a significant effect on the growth of plants.

3.Pharmaceutical prevention and control.

1) Soil disinfection before planting, seedbeds and planting fields can be disinfected with avermectin. After continuous use, the control effect of avermectin decreases year by year, and it is recommended to use it alternately with other disinfection technologies. Thiazophos is an excellent pesticide variety for the prevention and control of nematode disease, with high efficiency and low toxicity, and the effective period after drug is 2 to 3 months.

2) Furrow irrigation roots, with phosphine or avermectin, after planting. In the early stage of the disease, an appropriate amount of avermectin and chitin (with eggicidal effect) can be used to irrigate the roots, and the control is done once every 45 to 60 days. Pay attention to the rotation of medications.

The growth cycle is long, the yield is heavy, and the serious mu is divided into two times, the yield is light, the growth cycle is short, the amount of 2-5 kg per mu can be, killing more than 96%, patented products, only this one has been used for more than 20 years, and the validity period is more than 135 days.

The treatment of root-knot nematode disease should be based on prevention, there are many types of root-knot nematodes, and it is not a kind of root-knot nematode as a pest, so it is recommended to use comprehensive drugs. It is best to use avermectin with emulsifiable concentrate, and need to irrigate the roots, it is best to add drip irrigation after irrigation is conducive to the penetration of the medicine into the roots of the plant, plus some rooting powder, but avermectin is useless for eggs, but also add a little penicillium lavender that has an effect on eggs and insects to control root-knot nematodes, root-knot nematode disease is easy to cause other soil-borne diseases, so it is recommended that Trichoderma and Penicillium lavender are applied together.

Nematodes are subterranean worms that are common in potted flowers. It is a white thread-like mollusk insect that is not easy to see with the naked eye, and is very harmful to the callus of the young roots, young stems, bulbs, bulbs and cuttings of potted flowers. When the damage is severe, the aboveground part of the potted flower withers and dies.

The following methods can be taken to prevent and control:

When nematodes are found, if possible, they should be repotted, all the old soil should be removed, or the roots of the flowers and trees should be washed before repotting and planting. Nematodes can be fumigated with solutions such as methyl bromide and formaldehyde. After the potted flowers are watered thoroughly, cover the potting soil with a layer of 2 cm thick fine sand mixed with pesticides, the nematodes because the potting soil has been watered thoroughly, the air in the soil is insufficient, and soon burrow into the sand from the wet potting soil to breathe, and then remove the sand.

Do this 2 3 times can**.

He mainly harms the root system of the crop, and a lot of nodules grow on the root system when infected. When the damage is more serious, the plants on the ground will slowly become very slow to develop, and the leaves will become dull and yellow, which will directly affect the yield of the later fruits. There are also some roots that will rot, causing the plant to die, which is really very harmful.

The prevention and control has high temperature prevention and control, and the high temperature stuffy shed will kill all the bacteria and harmful bacteria in the soil.

Chemical control of avermectin has a fast effect, but there are pesticide residues, and it is easy to produce resistance, and the effect is becoming less and less obvious.

Although the effect of biological control and control line is not as fast as chemical control, there is no pesticide residue.

Prevention and control methods 1, agricultural measures.

Use insect-free soil for seedlings to raise. When transplanting, remove the insect-bearing seedlings or remove the "root nodules". Remove the carcass of the insect, reduce the density of the insect population, and burn the roots of the insect after drying.

Turn the soil deeply. Turning the topsoil below 25 cm can reduce the occurrence of insect infestations. Crop rotation for insect control.

In fields where nematodes occur a lot, changing to insect resistant (tolerant) crops such as grasses, onions, garlic, leeks, peppers, cabbage, cauliflower, etc., or planting aquatic vegetables can reduce the occurrence of nematodes. High (low) temperature inhibition insects. Take advantage of the high temperature in summer and the leisure season, ridge irrigation and mulching, and seal the shed for two weeks.

The occurrence of nematodes can be inhibited by using low-temperature freeze in winter.

2. Pharmaceutical prevention and control.

Soil treatment before planting: 10% gram phosphorus, 3% milel, 5% Yishubao and other granules can be selected, and 3 5 kg per mu can be evenly sprinkled and turned into the soil. You can also use one of the above-mentioned agents, 2 4 kg per mu in the ditch application on both sides of the planting line, or with the planting hole application, the amount of medicine per mu is 1 2 kg, and the soil mix after application prevents the root system from being in direct contact with the agent.