Root knot nematode damage control methods and treatment of specific drugs, root knot nematodes are more harmful. In general, root knot nematodes mainly damage the underground roots of plants, mostly occur on lateral roots and fibrous roots, forming nodules of varying sizes The vegetable peasant is called "sweet potato". The tumor-like root knot is white and smooth at the beginning, and then turns yellow-brown to dark brown. The surface is rough and even cracked, and it rots when it is severe. There is no sign of the appearance of the nodule. After the root of the root canal, the white pear-like body slightly larger than the needle is seen, which is the pathogenic female nematode, which is also the evidence for the diagnosis of this disease.
The pathogenic nematode overwinters the eggs in the soil. The larvae hatched by the eggs are called 2nd infested larvae, spread by rainwater and irrigation water, and invade from the young root tip until they develop into adults and become settled parasitic nematodes. At the same time as the needle acupuncture and feeding, the secretion is injected to stimulate the proliferation and enlargement of the host cells to form nodules. Usually sandy loam (soil but dry and wet, however), or even for the heavy disease.
Root knot nematode
In recent years, with the large-scale cultivation of vegetables, especially the establishment of greenhouses, many places have only planted one crop for a long time, without rotation, which has increased the severity of nematodes, especially in the old shed area, like Shandong Shouguang, root. knot nematode is most severe.
Root-knot nematode damage symptoms
The main hazards Meloidogyne root plants, especially lateral and fibrous, needle-stick injury kiss Meloidogyne root, salivation, destroy the root epidermal cells, which in turn destroy the host cell's normal metabolism so lesions, after which the roots will show different shape, affect the absorption of roots, to deliver nutrients, moisture, forming a withered plant floor, wilting, the performance is more severe at noon, the evening is slightly lighter, because the plants showed symptoms of wilt, fusarium wilt as it is easy to treat , delayed the timing.
Root knot nematode control measures
Comprehensive soil mixing application (most effective for controlling nematodes). It can also be applied in the face and applied in the ditch.
Before the crop is planted (on the day of planting), the agent is evenly spread on the surface of the soil at a dose of 1-2 kg/mu, and the agent and the soil are thoroughly mixed by a rotary tiller or a hand tool.
The depth of mixing of the medicinal and soil is 20 cm.
Root-knot nematode is one of the major pathogens of China's grain, vegetables and cash crops. At present, root-knot nematode has become a destructive disease of vegetables in northern protected areas, and it is also the main disease of fruits and vegetables cultivated in the south.
Four kinds of root-knot nematodes, peanut root-knot nematodes, Javanese root-knot nematodes and northern root-knot nematodes are the most common, and the damage to crops is also the largest. Root knot nematode mainly infects crop roots, but sometimes infects the leaves of tubers, bulbs, underground pods and greenhouse crops. There is no specific symptom in the aerial part. When the plant is seriously damaged, the leaves are small and yellow, the plants are dwarfed, and even the wilting is dead.
Root-knot nematodes usually have no obvious host specialization and can infect more than 2,000 plants. The root area of ​​vegetable root-knot nematodes in the country exceeds 20 million mu. The most seriously damaged vegetables are mainly vegetables such as Solanaceae (such as tomato, eggplant, and pepper) and Cucurbitaceae (such as various melons).
For example, tobacco root knot nematodes occur more severely in Sichuan, Chongqing, Henan, Yunnan, Guangxi, Hunan, Hubei, and Shandong, and continue to increase. With the rapid development of the industrialized production of banana tissue culture seedlings, the nutrition cups in the greenhouse are diseased, and the root knot nematodes are directly brought into the field during transplanting, resulting in the widespread occurrence of banana root knot nematodes.
In Guangdong, Guangxi, Hainan, Fujian, Yunnan, Taiwan and other provinces and cities, banana root-knot nematode disease is serious, the incidence rate is generally 20% to 30%, severely more than 60%, yield reduction of 40% to 60%, seedling stage Seriously affect the rate of occurrence. At the same time, the infection of root-knot nematodes is closely related to the occurrence of banana bunchy disease, which poses a serious threat to banana production.
The second instar larvae are the only insects infecting the roots of crops, and are also the key insects in the control of root knot nematodes. The second instar larvae invaded from the root tip of the crop.
It has been the main reason for the occurrence of root-knot nematode diseases by planting the same vegetable variety for many years. The re-production and re-emergence of diseased greenhouses has accelerated the spread of spread. The traditional flood irrigation is an important way to spread the root-knot nematodes of greenhouse vegetables. The soil environment (sand soil, dryness, etc.) is suitable for the development of root-knot nematodes. Growers pay attention to management, mode of administration, misuse of pesticide varieties, also contributed nematodes serious reasons.
With the expansion of cultivated area of ​​protected vegetables, the damage of root-knot nematodes has become a prominent problem in production, and its occurrence is on an upward trend. The yield loss is 30%-50%, and the seriousness is over 70%. Therefore, the vegetable roots The prevention and treatment of nematode disease has become particularly important.
First, the occurrence of root knot nematode disease in vegetables
(a) harmful symptoms
The root-knot nematode is mainly responsible for the roots of vegetables. The prominent symptoms are the formation of tumors of different sizes in the roots, and some rhizobium resembling legumes. Using a needle to pick up a tumor, you can see a nematode with a needle tip size inside the tumor. The root part of the root knot often produces small new roots, which are later infected to form root-like swelling.
Because the roots of vegetables are harmed by nematodes, most of the aboveground parts show growth and decline, and the leaves turn yellow, and the serious whole plants wither and die. In addition to the tumor, the root has no other special manifestations, but it is stunted, the roots are small and small, especially the root reduction is more obvious, and some are accompanied by root rot symptoms.
(2) Law of occurrence
The entire life history of nematodes must pass through three stages: eggs, larvae and adults. In the field, nematodes overwinter in the soil with eggs or other insect states. It can survive for 3 years without the presence of host plants in the soil. When the temperature reaches above 10 °C, the eggs can hatch out larvae, and the larvae invade from the root hairs or root cortex. Stimulate the host cell to accelerate the division, so that the affected part forms a nodule or root knot.
The nematode has a small range of activity in the soil and cannot be spread over long distances by its own activities. The long distance is mainly transmitted by diseased soil, diseased seedlings or roots and tubers with nematodes. Nematodes need more air, so the terrain is dry, the texture is loose, and the well-ventilated sandy soil is beneficial to nematodes.
Soils that are low in moisture and heavy in weight are not conducive to occurrence. The distribution of nematodes in the soil is mainly in the range of 10 cm to 30 cm deep, and the soil temperature below 12 ° C or higher than 28 ° C is not conducive to nematode activity. If the soil is immersed in water for more than 100 days or dried for a long period of time, the nematode will die. The optimum temperature for root knot nematode development is 25-30 °C, and it takes 25-28 days for breeding at 27 °C. The larvae stop moving at 10 °C, and die at 55 °C for 10 minutes.
(3) Reasons for the occurrence
The cause of a large number of nematodes: the use of highly toxic pesticides to root, not only destroys the roots of the crops, but also destroys the living environment of the beneficial microorganisms in the roots of the soil, breaking the soil balance, causing a vicious circle, causing the nematodes to become more and more serious.
(4) Why is it difficult to cure?
Because root-knot nematodes live underground, it is difficult for vegetable farmers to grasp the law of their activities, so it is difficult to find the best prevention and treatment methods. At the same time, their rapid transmission speed and inconsistency in medication are the causes of refractory root-knot nematodes. In the battle with root-knot nematodes, vegetable growers are always passive. Vegetable farmers are more focused on “ruling†in the concept of plant protection, while ignoring “defense†and putting the cart before the horse, resulting in poor results.
Second, vegetable root knot nematode prevention and treatment methods
(1) Agricultural control
1. Rotating vegetable fields with root-knot nematodes, it is best to carry out rotations, especially rice, onions, garlic, etc., to better control root-knot nematodes. Do not rotate with vegetables that are prone to worms such as eggplant, tomato, celery, lettuce, carrots, etc.
2, seedbed disinfection or soilless seedling seedling bed is one of the important ways of root-knot nematode transmission. If the seedbed is not treated, it is easy to spread the root-knot nematode to the field, and the early damage of the crop is affected by the root-knot nematode. Great impact. The use of soilless seedlings is an important measure to avoid root knot nematodes. If the area of ​​the seedbed is large, the seedbed disinfection measures can be adopted. 35% Weibaimu water agent (8-10kg/mu) is thoroughly mixed with the soil, and then covered with plastic film fumigation.
3, flooded insecticidal heavy disease field irrigation 10-15cm deep, 20-30 days, so that the nematode suffocation and death. It is best to use this season of rice to kill both nematodes without causing ridiculous fields.
4. Deep root-knot nematodes are mostly distributed in the topsoil, and deep turning can reduce damage. Deeply ploughing before sowing, deep turning over 20cm, turning the possible nematodes into the depth of the soil can reduce the damage.
5. The use of varieties or rootstocks resistant to root-knot nematodes to select disease-resistant or disease-tolerant vegetable varieties can greatly alleviate the damage caused by various diseases.
Relatively, tomato varieties have high resistance to root-knot nematodes, and Israeli tomato varieties FA-593 and FA-1420 are more resistant to nematodes.
Rootstock varieties: cucumber seed grafting can choose black seed pumpkin, green anvil No. 1, all-purpose iron armor; watermelon and melon grafting use all-purpose iron armor, green anvil No. 1, Qingnong rootstock No. 1; eggplant grafting use Torumba, Totosga Etc.; the grafting of peppers was selected from Buyeding, Weizhuang Bell, Rootstock No. 1, and Rootstock No. 2; tomato grafting was selected from Qiong No. 2, Torumba, JZM-1, Mandala, and Millennium.
(2) Physical control
1. Steam disinfection: Steam disinfection is harmless to humans and animals, and it is used repeatedly without the resistance of harmful organisms. The methods of steam sterilization include surface film disinfection method, buried underground pipeline method and negative pressure disinfection method, and the negative pressure disinfection method has the highest efficiency. Root-knot nematodes are sensitive to heat and remain at 10 ° C for 10-15 minutes, killing almost all nematodes.
2, soilless cultivation: soilless cultivation is an important agricultural measure that can effectively avoid root knot nematodes. According to the research, the cultivation substrate composed of rice husk, crop straw and animal waste material is used to grow vegetables, which has the advantages of low cost, simple technology and high quality of products, and has broad application prospects.
Soil cultivation tank specifications: upper mouth width 35cm, bottom width 25cm, depth 25cm; two groove spacing 1.5m, cultivation matrix formula (volume ratio): formula one, rice husk: fermented chicken manure: river sand = 3:1:1 Formula 2 is, decomposed cow dung: rice husk: river sand = 5:4:1; formula 3 is, corn or wheat straw fermentation material: decomposed chicken manure (sheep dung): river sand = 4:1:1. Substrate dosage standard: The dosage of facilities fruits and vegetables (tomato, cucumber, sweet pepper, zucchini, etc.) is about 34m3/666.7m2, and the cost is about 2500 yuan/666.7m2.
Fertilizer application rate: N, P2O5 and K2O and other topdressing amount = various nutrient components (kg/ha) to be absorbed by the target yield of vegetables × 1.5 - various nutrient components (kg/ha) that the substrate used can provide - the matrix used is delayed Nutrient conversion (kg/ha).
The various nutrient components that should be absorbed by the vegetable target yield can be obtained from published materials; the various nutrient components provided by the matrix can be obtained from the determination of the matrix; the matrix delayed nutrient conversion can be applied to the substrate after the vegetable crop is harvested. Obtained in the measurement. By calculation, the fertilizer application rate of the three matrix formulations is about 30-50kg/666.7m2 of urea and 75-95kg/666.7m2 of potassium sulfate (the target yield of tomato is 7500kg to 10000kg/666.7m2).
3. Sunlight disinfection: (1) After sun-sterilized vegetables are harvested, in the hot season of summer, after ploughing and watering, the film is covered and exposed for 5-7 days, so that the temperature of the 20-25 cm soil layer under the film is raised to 45-48 °C or even 50 ° C, combined with high humidity (relative humidity reaches 90% -100%), the insecticidal effect is good. This method is easy to operate, good in effect and low in cost.
(2) Daylight + wheat straw From late June to late July, a 30cm deep ditch shall be opened in the solar greenhouse according to the row spacing of the crops, and 3000kg of wheat straw or corn stover, Jiameili 400g, 50kg ammonium bicarbonate and 5-6m3 chicken shall be laid in each acre. The manure and part of the topsoil are ridged (the wheat straw is below), and the greenhouse film and the mulch are used to permeate the water to ferment the straw. According to the experiment of Shandong Academy of Agricultural Sciences, the control effect was 73.3% in the solar greenhouse where cucumber root knot nematode disease occurred seriously.
(3) Daylight + Lime Nitrogen + Wheat Straw During the period from May to July, the greenhouse vegetables in the greenhouse are idle, and the application of lime nitrogen (calcium cyanamide) 50-100kg, broken wheat straw 600-1300kg, ploughing, ridges, covering the mulch, Watering, treatment for 20-30 days, peeling off the film and drying it for 8-10 days. If the roots are irrigated with 1000 times of avermectin after colonization, the damage of root-knot nematodes can be more effectively controlled. After the above treatment, the control effect on root knot nematode disease was 89.5%.
(3) Chemical control
1. The effect of avermectin is comparable to that of methyl bromide soil, and the cost is significantly lower than that of methyl bromide.
Celery: 1 ml of 1.8% avermectin EC per square meter, diluted 1000 times, sprayed with a sprayer, and mixed with the soil. The control effect is 83%.
Cucumber, bitter gourd: Ditch or water the avermectin 1000 times solution at the time of planting. The control effects of cucumber and bitter gourd were 86% and 70%, respectively.
2, cotton long also known as speed will be extinguished. During the greenhouse shed, 98% cotton granules were evenly applied to the soil surface at a dosage of 20-30 g/m2, mixed with the soil with tweezers, and then sprinkled with water on the surface of the soil and covered with plastic film for 4 weeks. After the film is released, the gas is removed, and the soil is transplanted. It is also possible to flip the soil to a depth of 20 cm immediately after the medicine is applied, and the cover film is sealed and filled with water. After 7-10 days, the film is peeled off, the soil is loosened 1-2 times, and the crop is planted after 7-10 days.
Medan is usually a microparticle. If the application is not uniform, the drug is harmful in places with large doses, and the effect is not good in small doses. It must be applied evenly. The disadvantage is that the cost of treating the soil with chemicals is higher.
3. Weibaimu Weibaimu produces insecticidal, bactericidal and herbicidal effects by producing methyl isothiocyanate in the soil. Usually used as 40% water. In the greenhouse, greenhouses during the soil treatment, the use of the method is to first well, and then cover the plastic film, through the drip irrigation system, the amount of 17.5-35g per square meter (Active Ingredient), according to soil moisture, per acre The water intake is 20-40m3.
After 4-6 weeks of cover film in summer, the film was released 1 week before transplanting and transplanted. Or a ditch with a line spacing of 15cm and a depth of 15cm, which is poured with water at a dosage of 3-5kg per mu to cover the mulch. After 7 days, the film was peeled off, the soil was loosened 1-2 times, and the crop was planted after 7 days. The test results of using 40% Weibaimu water to control cucumber root knot nematode showed that the control effect can reach 60%. The use of Weibaimu is best combined with solar disinfection.
4, Miller, Yi Shu Bao Mi Leer, also known as chlorpyrifos, is an efficient, broad-spectrum organic phosphorus agent with insecticidal and nematicidal effects, with systemic and contact killing, stomach toxicity, can Prevention and treatment of various nematodes. It is commonly used as a 3% granule.
Yishubao, also known as keke phosphorus, is an organophosphate nematicidal and insecticide that is a contact killer. Commonly used as 10% granules.
Use 3% Miller or 10% Yishubao, 4-5kg per acre, used twice. The experiment was carried out in a greenhouse where the stalk was cucumber and the worm disease occurred severely. Test agent 3% Miller granules (Swiss), 10% Yishubao granules (made in France). The application period was divided into 10 days before the application and 10 days after the sowing. There are three treatments of 3kg, 4kg and 5kg per acre, and each concentration treatment is divided into 1 time and 2 times.
Yishubao and Miller have good effects on the control of vegetable nematodes, and the best dosage is 5kg per acre. In the case of the same dosage, the drug is administered twice and once, and the control effect is more than 1 time after 45 days of the drug, indicating that the drug can be effectively controlled for at least 2 times during the whole growth period of the cucumber.
5. 1,3-Dichloropropene can significantly reduce the incidence of tomato root-knot nematode disease and stimulate plant growth. The method of use is as follows: ditch according to the sowing line; press 15% perennial emulsifiable concentrate 15kg per acre, dilute with water 10 times, pour in the ditch, immediately cover the soil; cover soil, cover film; seal fumigation for 7 days; Remove the mulch film, draw the application ditch, loosen the soil for 7 days; sow or transplant.
6, thiazolyl product name is more blessing. The use of 10% Fuqi multi-granules has a good control effect on cucumber root knot nematode disease. The dosage per acre is 1.3-2.0kg, the control effect can reach more than 77%, and the yield increase is over 38%. How to use: Mix the medicinal agent with fine sand at a ratio of 1:20 before applying. Spread half of the medicine evenly on the soil surface, rotate 20-30cm, level the ground, then open the planting ditch, sprinkle the other half of the medicine into the planting ditch, and mix with the soil.
7. In addition, heavy application of decomposed organic fertilizer, application of phosphorus, potassium and micro-fertilizers to improve disease resistance of plants, application of lime in base fertilizer, and application of superphosphate leachate in leaf surface can also significantly control and alleviate diseases. Organic ecological soilless culture techniques can also fundamentally eliminate the occurrence of root-knot nematodes.
This article URL: Root knot nematode damage prevention methods and treatment specific drugs [Figure]
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