At present, the soil throughout the country, root knot nematodes are becoming more and more intense, has been known as the first major disease in the vegetable area, the national vegetable root knot nematode occurrence area of more than 20 million mu, resulting in agricultural losses of up to 70 billion yuan! Even many fruit tree areas cannot be avoided! Light yield loss in 20%-40%, serious up to 70% or more, and some even fail to harvest!
1. Recognize root-knot nematodes
Nematodes, also known as root-knot nematodes, is a highly transformative omnivorous plant pathogen nematodes, known to be harmful to vegetables mainly include high toxocarpus knot nematodes, peanut root knot nematodes (there are about 330 kinds of infested crops), northern root knot nematodes (about 550 kinds of infected crops), southern root knot nematodes, Java root knot nematodes and beet root knot nematodes, etc., which can infringe on more than 3,000 crops in 114 families.
Nematodes are invisible to the naked eye and under the microscope the larvae are elongated worm-like, male adults are linear, and female adults are pear-shaped.
Root-knot nematodes are mainly distributed in surface soils of 3-10 cm, and rarely exist in soils below 20 cm. Nematodes reproduce quickly at soil temperature of 25 to 30 °C and soil moisture of 40% to 70%, stop their activities below 10 °C, and die at 55 °C for 10 minutes (eggs can survive). Survive for up to a year without a host!
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Root-knot nematodes are harmful symptoms
Root-knot nematodes can harm a variety of crops
Generally harmful symptoms
Mainly harmful to the roots, pathogenic nematodes parasitize between the root bark and the middle column, so that the root tissue overgrows, resulting in the formation of rhizobia of different sizes.
Therefore, the root is nodular and enlarged, which is the main symptom of the disease. Most nodules occur on fine roots, and when the infection is severe, secondary nodules can appear, and a large number of small roots occur, so that the root system is coiled into clumps and forms a whisker root mass. Because the root system is damaged, affecting normal function, making it difficult to transport water and nutrients, coupled with the rot of old mature rhizomas, and finally necrosis of diseased roots. Under the general incidence of disease, there are no obvious diseases in the aboveground part of the diseased plant, but as the root damage gradually becomes serious, the canopy appears weak branches, smaller leaves, growth decline and other pathologies. When the damage is more severe, the leaves are yellowish and dull, and the leaf margins are curled and water-dehydrated.
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Root-knot nematode infestation process
The damage process of root knot nematode infestation is mainly: nematodes first invade the host first to contact or reach the root circumference that can be affected by the host's extravasation, begin to grow at the invasive site, and then multiply and expand in the plant, gradually form a linear tumor in the root, produce pathogenic effects, root nodules protrude, decay, poor growth, and root, and then produce many egg blocks after containing many female insects in the old mature rhizoma, and continue to reproduce and grow!
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The reason why nematodes are difficult to control
1, the variety of reproduction speed is very fast: root knot nematode can be both sexual reproduction, can also be parthenogenetic reproduction, each egg sac has 300 ~ 800 eggs, a year can breed 5-10 generations, and generations overlap
2, insect eggs survive strongly, not easy to kill: although a large number of chemical control agents kill the nematodes adults, but the eggs are only poisoned into the dormant period, in the right temperature environment, and can resume growth, re-infect the harmful crops, some people use to reduce or increase the soil temperature, kill nematodes, but some cystic nematode eggs, can also survive in the soil for 2-5 years, some nematode eggs can survive for 28 years in the absence of a host in cold areas.
3, the expansion of the breeding environment: there are many vegetables, orchards use unripe organic fertilizer, especially chicken manure, containing a large number of nematode eggs, while the greenhouse for the nematodes to provide breeding places, so that the nematodes have a suitable winter habitat, so that the nematodes team gradually expanded, the harm is serious year by year!
4. Cultivated varieties do not have strong resistance to line: cucurbitum, watermelon, melon, loofah, bitter melon, etc., including grafted rootstock, have no line resistance varieties. Legume vegetables (kidney beans, carobs, lentils, knife beans, etc.) also have no line varieties.
5, farmers have poor awareness of prevention and control: nematode disease focuses on prevention, not treatment. The initial symptoms of nematode disease are in the underground part, which is easily ignored by farmers, and when it is found, the symptoms are already more serious, and it is difficult to prevent and control! Most of the chemical control agents are to kill adult nematodes, and the killing of insect eggs is not strong. And the next generation of nematodes will become resistant and resistant to chemical pesticides!
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Commonly used prevention and control methods
First, agricultural control (insect eggs are basically not dead)
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Use "insect-free soil" seedlings
Reduce the density of the worm population
Remove the seedlings or remove the "nodules" during transplanting, remove the remnants of the insects, reduce the density of the insect mouth, and burn the roots of the insects after drying.
Deep turn the soil
Because root-knot nematodes are mainly distributed in the topsoil of 3-10 cm, turning the topsoil below 25 cm can reduce the occurrence of insect pests.
Take turns to prevent insects
In fields where nematodes occur a lot, it is possible to reduce the occurrence of nematodes by changing to insect-resistant crops such as grasses, green onions, garlic, leeks, peppers, kale, cauliflower, etc., or planting aquatic vegetables.
High (low) temperature suppressor
Taking advantage of the summer high temperature leisure season, the ridge is filled with mulch film and the shed is closed for two weeks. The use of low temperature freeze in winter can inhibit the occurrence of nematodes.
Second, the electrical treatment method (the cost is too high, it is not easy to operate)
It can be controlled by soil electric disinfection method or soil electric treatment technology. Root knot nematodes have weak resistance to current and voltage, and the use of electric treatment machines to apply voltages of 30-800 volts in the soil, the current exceeds 50A/㎡ can effectively kill the root knot nematodes in the soil.
III. Prevention and control of microbial bacteria (recommended)
Purple spore fungus
Using the hyphae produced by the germination of purpurea, it penetrates the egg shell of the nematode, the wall of the larvae and the female adult, and the hyphae absorb nutrients in their bodies, reproduce, and secrete toxins and chitinase at the same time, destroying the normal physiological metabolism of eggs, larvae and female adults, resulting in the death of nematodes.
Complex microbial bacteria
The complex microbial flora of compound purple purpuria and Trichoderma harzum has a strong affinity for nematode egg protein, and its unique hyphae can penetrate the egg epidermis within 24 hours, so that the lipid layer and chitin disintegrate, the egg epidermis and somatic cells rapidly shrink and dehydrate, and then die and dissolve, using Trichoderma hatha to produce antibiotics, increase permeability to dry out the fungal spores, destroy the growth of the spore germination tube by destroying the cell membrane, inhibit the growth and colonization of pathogenic bacteria, and block the transmission of energy required for the reproduction and growth of pathogenic bacteria. It can not only significantly inhibit the infestation of nematodes, but also promote the growth of plants and plant vegetative organs, improve the microenvironment of the root system, and improve the soil environment.
Up and down (biological defense line)
Can be flushed and drip irrigated
This product is composed of Coccidioides albicans, Pachychia pachyderma and other active ingredients, Coccidioides albicans is a broad-spectrum insecticidal fungus that destroys the insect tissue by penetrating the body wall of insects and infecting the odd main body. Rotunda pachyderma is a facultative parasitic bacterium, which is applied to the soil to quickly germinate nematode bacteria to form hyphae, and puncture the eggs and nematodes of nematodes to achieve the purpose of preventing and controlling nematodes.
Advanced carrier, double bacteria, one fertilizer, three effects in one, rich in mineral-derived fulvic acid, carbonase proto-powder, amino acids, alginic acid and other crop active genes and large, medium and trace elements. And can quickly replenish the organic matter in the soil, loosen the soil, drought resistance and water retention, promote root growth, seedlings and seedlings increase crop photosynthesis, improve crop disease resistance, stress resistance, and significantly reduce the phenomenon of dead seedlings and rotten roots, roots, rotten heads, dead trees and so on. Promote the healthy growth of plant roots, resist heavy stubble, improve quality, increase production and income. The adsorption carrier is rich in marine refining and double-acting bacteria, which can effectively prevent underground pests from invading the plant.
Nematodes that have invaded the body of plants can also be effectively repelled and have a strong inhibitory effect.
It has the characteristics of efficient control of nematodes, resistance to heavy stubble, and control of soil-borne diseases