Composition for preventing and controlling rice root-knot nematodes during rice seedling stage, preparation method and application thereof

Abstract

The present invention discloses a composition for controlling rice root-knot nematodes during the rice seedling stage, as well as its preparation method and application, and belongs to the field of agricultural technology. The composition of the present invention comprises a hemp fiber film adsorbed with fluopyram for wrapping rice seedling trays, a nematode-resistant rice seedling substrate, and a rice seed coating agent; the seedling substrate comprises biochar, mineral-derived potassium humate, plant nutrient soil, perlite, vermiculite, rice straw fiber adsorbed with avermectin, amino oligosaccharide powder, and tea seed meal; and the coating agent comprises Purpurosporium lilacinum, a biomimetic component of PDA potato dextrose agar culture medium, and a viscous dispersant. The present invention also discloses a preparation method for the composition and its application for controlling rice root-knot nematodes during the rice seedling stage. Using the composition of the present invention for rice seedling cultivation results in strong soil-breaking ability of rice sprouts, high soil-breaking rate and germination rate, high seedling survival rate, uniform and good growth, and reduced root-knot nematode infestation.

Description

Technical Field

[0001] The invention belongs to the technical field of agriculture, and particularly relates to a composition for preventing and controlling rice root-knot nematodes during the rice seedling stage, and a preparation method and application thereof. Background Art

[0002] Plant-parasitic nematodes (PPNs) cause over $80 billion in economic losses to global agriculture annually. Meloidogyne spp. and Heterodera spp. are particularly devastating, causing both socioeconomic losses and crop yield losses. The main Meloidogyne spp. species that damage rice include M. graminicola, M. incognita, M. javanica, M. oryzaeh, M. arenaria, and M. salasi. These species are considered the most threatening to rice, causing severe plant diseases and economic losses.

[0003] The root-knot nematode (M. graminicola) of the Poaceae family, commonly known as the rice root-knot nematode, is the main pathogenic nematode that causes rice root-knot nematode disease. It is the most common plant-parasitic nematode in rice systems and the plant-parasitic nematode that has the most serious impact on rice yield.

[0004] The root-knot nematode (Meloidogyne graminicola) is a sedentary endoparasitic nematode that adapts to flooding. It can survive in both dryland and irrigated rice plants, as well as in deepwater ecosystems, where it is one of the three main pathogenic nematodes. In rice, infection by the root-knot nematode induces the formation of root knots, primarily a characteristic hook-shaped knot at the root tip, which severely impairs root growth and development.

[0005] Rice root-knot nematode disease affects approximately 50% of rice plants and can result in a 30% reduction in crop yield. Due to the destruction of the root vascular system, water and nutrient transport is inhibited, leading to symptoms such as stunting, yellowing, and loss of vigor in rice plants, ultimately resulting in poor crop growth and significant yield losses. In deepwater rice fields, it can cause rice plants to drown, resulting in severe yield losses. Infected seedlings cannot grow above the water surface, leaving patches of open water in flooded paddies. Studies have shown that under simulated dryland or intermittent flooding conditions, yield losses caused by root-knot nematodes in the Poaceae family range from 20% to 80% and 11% to 73%, respectively.

[0006] The root-knot nematode (M. graminicola) is well adapted to flooding and can survive for long periods in moist soil as oocysts or larvae. Its population declines rapidly after four months in the soil, but some oocysts can remain viable for at least 14 months in flooded soil. It can also survive for at least five months in soil flooded to a depth of one meter. However, it cannot invade rice plants under flooded conditions. When the soil is drained, it rapidly invades rice plants and thrives within the roots of infected plants. The optimal soil moisture for its growth and development is 20%-30%. Dry conditions also favor its growth and reproduction during the tillering and heading stages of rice. The nematode population gradually increases as infected rice plants grow. Temperatures between 22-29°C are most conducive to the spread of the root-knot nematode.

[0007] The root-knot nematode (MPN) undergoes four molts throughout its life cycle. The first molt occurs within the egg, and the newly hatched second-instar larvae (J2) are the active instars for infesting the host, typically congregating around the elongation zone of rice roots. Many larvae also hatch within the roots and re-infest by migrating within the roots to new feeding sites within the same root system. Female M. graminosa remains within the root knots, where eggs are deposited as egg sacs within the root cortex. Studies have found up to 50 egg-laying females in a single root knot, suggesting that the number of nematodes infesting each root system can be very high.

[0008] 1. Symptoms of Rice Root-Knot Nematode Disease

[0009] The root tips are affected, becoming twisted and thickened, swelling to form nodules. Initially oval and white, the nodules develop into oblong shapes with slightly pointed ends. They range in color from brownish-yellow to brownish-brown, and even black, measuring 3 x 7 mm. They gradually soften and rot, and the outer bark easily cracks. When nodules appear on one-third of the root system during the seedling stage, the plant is weak, with pale leaves and a slow return to green. During the tillering stage, the number of nodules increases significantly, resulting in stunted plants with yellow leaves, thin stems, short roots, and weak growth. During the heading stage, the plant is dwarfed, with fewer and shorter ears, often half-enclosed or with leaves enclosing the ear nodes. The fruit set rate of those that can produce ears is low, and many grains are barren.

[0010] 2. Transmission routes of rice root-knot nematode disease and factors affecting its incidence

[0011] The primary sources of rice root-knot nematode infection are diseased soil and seedlings. The disease can be spread by water, fertilizer, farm tools, people, and livestock. First- and second-instar larvae overwinter in root nodules. The second-instar larvae invade the rice roots in the following year, stimulating the formation of root nodules. After maturing, female worms lay eggs in the nodules, which then form first-instar larvae. After a single molt, the second-instar larvae emerge from the nodules, leaving the nodules and roaming in the soil and water, invading new roots. Infection is most severe during periods of high root production. The nematodes only infect new roots. The disease is most severe in acidic and sandy soils. Continuous cropping of rice is more severe, while rotational rice cultivation is less severe. Paddy fields are more susceptible, while dry land is less susceptible. Aside from seedlings, the main infection periods are the tillering and panicle differentiation stages. The tillering stage, when roots are abundant, is ideal for infection and results in severe damage. Furthermore, different rice varieties vary significantly in their resistance to nematode infection.

[0012] 3. Methods for controlling rice root-knot nematode disease in existing technologies

[0013] 1. Strictly prevent diseased seedlings from spreading to disease-free areas. Liming diseased fields can significantly reduce nematode infestation, but the timing of application is crucial. Apply 75-100 kg of lime per mu before planting or after the plants have returned to green. Applying lime before rice tillers is most effective in protecting new roots and reducing infection.

[0014] 2. Practice a wet-dry rotation in rice fields. After harvesting rice, plant non-host plants to reduce the insect source and mitigate disease. This is the most economical and effective measure. For severely infested fields, a wet-dry rotation approach, planting peanuts and sweet potatoes for six months, can significantly reduce soil insect populations. However, crop rotation alone cannot completely cure the disease, and it can easily lead to recurring root-knot nematode infections.

[0015] 3. Conventional chemical control: Because rice root-knot nematodes are more damaging at the beginning and end of the year than in the middle, chemical control should focus on the rice seedling stage and the post-harvest rice stubble stage. Nematicides are typically applied to the rice seedling field.

[0016] For seedling control, mix 1.5% avermectin granules or 10% thiazolyl granules with the bottom seedbed soil and cover with a layer of soil before sowing. For fields affected by rice root-knot nematodes, soak the roots with pesticides before transplanting. Use thiazolyl, fluopyram, or Paecilomyces lilacinus.

[0017] Field control: In the early stage of the disease, 3-4 kg of 0.5% avermectin granules, 1.5-2 kg of 10% thiazolinone granules, or 50 ml of 41.7% fluopyram suspension concentrate can be applied to the paddy field with 15-30 kg of soil to make poisoned soil for application. There should be a shallow water layer in the field.

[0018] The aforementioned control methods using chemical pesticides are difficult to achieve below the economic threshold due to the complex soil environment and limited exposure to the pesticide. Effective control results in overdose, which can lead to pesticide damage and potentially impact the safety of humans, livestock, poultry, and fisheries. Therefore, providing a composition for controlling rice root-knot nematodes during the rice seedling stage that not only effectively controls rice root-knot nematodes but also promotes the growth and development of rice sprouts has become a pressing issue for those skilled in the art. Summary of the Invention

[0019] One of the purposes of the present invention is to provide a composition for controlling rice root-knot nematodes during the rice seedling raising stage. When the composition is used for rice seedling raising, the rice sprouts have strong soil-breaking ability, high soil-breaking rate and germination rate, high seedling survival rate, uniform and good growth condition, and the root system is less susceptible to root-knot nematode infection.

[0020] A second object of the present invention is to provide a method for preparing the composition.

[0021] The third object of the present invention is to provide an application of the composition.

[0022] A fourth object of the present invention is to provide a method for controlling rice root-knot nematodes during the rice seedling stage, using the above composition.

[0023] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0024] The present invention discloses a composition for preventing and controlling rice root-knot nematodes during the rice seedling raising period, comprising a drug-carrying hemp fiber film for wrapping a rice seedling raising tray, a nematode-resistant rice seedling raising matrix, and a rice seed coating agent;

[0025] The drug-carrying hemp fiber membrane is a hemp fiber membrane adsorbed with fluopyram;

[0026] The nematode-proof rice seedling medium comprises, by weight, 35-45% biochar, 2.0-3.0% mineral potassium fulvic acid, 15-25% plant nutrient soil, 3-8% perlite, 2.0-3.0% vermiculite, 15-25% rice straw fiber adsorbed with avermectin, 3-8% amino oligosaccharide raw powder, and 3-8% tea meal.

[0027] The rice seed coating agent is used for coating soaked rice seeds. Calculated based on 1 kg of dry rice seeds, the rice seed coating agent comprises 8-12 g of purpurogenous fungi, 15-25 g of a biomimetic component of a PDA potato dextrose agar medium, and 8-12 g of a viscous dispersant.

[0028] In some embodiments of the present invention, the nematode-proof rice seedling medium includes, by mass, 40% biochar, 2.5% mineral potassium humate, 20% plant nutrient soil, 5% perlite, 2.5% vermiculite, 20% rice straw fiber adsorbed with avermectin, 5% amino oligosaccharide raw powder, and 5% tea meal.

[0029] The biochar of the invention comprises walnut shell biochar and coconut shell biochar, and the mass ratio thereof is 12-18:22-28.

[0030] In some embodiments of the present invention, a method for preparing rice straw fibers adsorbed with avermectin comprises the following steps: soaking the rice straw fibers in a mixture of avermectin emulsifiable concentrate and water to fully soak the fibers, then removing the fibers and drying them in the shade;

[0031] Preferably, the length of the rice straw fiber is 0.8 to 1.2 cm;

[0032] Preferably, at least 1 kg of a mixture of avermectin emulsifiable concentrate and water is used for every 1 kg of rice straw fiber;

[0033] Preferably, the mixture of avermectin emulsifiable concentrate and water is prepared by mixing 10-20 ml of avermectin emulsifiable concentrate with 400-500 ml of water, and the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %;

[0034] In some embodiments of the present invention, based on 1 kg of dry rice seeds, the rice seed coating agent includes 10 g of Purpurosporium lilacinum, 20 g of PDA potato dextrose agar medium biomimetic component, and 10 g of a viscous dispersant.

[0035] In some embodiments of the present invention, the biomimetic components of the PDA potato dextrose agar medium contain, by mass percentage, 55-65% potato flour, 30-40% glucose powder, and 3-8% polyacrylamide;

[0036] Preferably, it contains 60% potato flour, 35% glucose powder and 5% polyacrylamide.

[0037] In some embodiments of the present invention, the effective viable count of the Pseudomonas lilacinus is ≥ 200 million / g.

[0038] The viscous dispersant includes glutinous rice flour.

[0039] The present invention discloses a method for preparing a composition for controlling rice root-knot nematodes during the rice seedling stage, comprising the following steps:

[0040] Step 1. Prepare drug-coated hemp fiber membrane: soak the hemp fiber membrane in a diluted solution of fluopyram suspension, take it out, and air-dry it naturally;

[0041] Preferably, the diluent of the fluopyram suspension concentrate is 0.1-0.5 ml of fluopyram suspension concentrate diluted with water to 15-60 ml;

[0042] Preferably, a 60cm*60cm hemp fiber membrane is evenly soaked with 15-60ml of a diluent containing 0.1-0.5ml of fluopyram suspension;

[0043] More preferably, the content of fluopyram in the fluopyram suspension concentrate is 41.7%;

[0044] More preferably, a 60 cm*60 cm hemp fiber membrane is evenly soaked with 30 ml of a diluent containing 0.2 ml of a fluopyram suspension;

[0045] Step 2. Prepare the nematode-proof rice seedling medium: uniformly mix the components of the nematode-proof rice seedling medium according to a certain proportion;

[0046] Step 3. Prepare the rice seed coating agent: uniformly mix the components of the rice seed coating agent according to a certain proportion.

[0047] The invention discloses an application of the composition in preventing and controlling rice root-knot nematodes during the rice seedling raising stage.

[0048] The invention discloses a method for preventing and controlling rice root-knot nematodes during the rice seedling raising stage, which is carried out by adopting the above-mentioned composition.

[0049] In some embodiments of the present invention, a method for controlling rice root-knot nematodes during the rice seedling stage comprises the following steps: coating soaked rice seeds with the rice seed coating agent; growing rice seedlings with the coated seeds using a nematode-resistant rice seedling substrate; and covering the bottom and inner sides of the rice seedling tray with a layer of drug-coated hemp fiber membrane.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The present invention is scientifically designed and ingeniously conceived. It creatively utilizes drug-containing hemp fiber membranes, anti-nematode rice seedling substrates, and rice seed coating agents to exert multi-angle and multi-level effects, jointly playing the role of preventing and controlling rice root-knot nematodes. The key stage for preventing and controlling rice root-knot nematodes is the seedling stage. Rice seedlings that are not infected by root-knot nematodes during the seedling stage are not easily infected in water after transplanting and can grow normally and healthily. When the composition of the present invention is used for rice seedling cultivation, the rice sprouts have strong soil-breaking ability and can all break through the soil within three days. The soil-breaking rate and budding rate are both as high as 100%. The seedlings have strong root systems and a high survival rate, which can be as high as 100%. The growth condition is uniform and good, and the root system reduces the infection of root-knot nematodes by more than 80%. After 24 days of seedling cultivation, the rice can be planted by machine transplanting, which is worthy of market promotion and application.

[0052] The present invention adopts the hemp fiber membrane double layer that is adsorbed with fluopyram to cover the bottom of the seedling tray. The hollow part can be breathable and water-permeable, does not affect the normal oxygen and water supply of rice seedlings, and can form two layers of protective barriers again, which can double (twice) prevent the rice root-knot nematode in the seedling field from invading the root system of the rice seedlings. In addition, the hemp fiber is complicated and confusing. After being soaked in water, the surface of the hemp fiber membrane will be drawn into a dense mesh, which will stick to and restrain the rice root-knot nematode that wants to migrate into the seedling tray. This mesh adhesion can delay the time when nematodes enter the seedling tray, and on the other hand, nematodes stay on the surface of the hemp fiber membrane and allow fluopyram liquid to contact nematodes for a longer time, which greatly enhances the nematode killing effect of fluopyram liquid and can greatly reduce the application amount of fluopyram liquid. Hemp fiber is environmentally friendly and biodegradable, and environmentally friendly without residue. The invention fully solves the problem in the prior art that fluopyram liquid is conventionally used by spraying or root irrigation, both of which work in the substrate soil. However, the soil composition and structure are complex, and the nematodes have limited opportunities to come into contact with fluopyram liquid, so the nematicidal effect is greatly reduced.

[0053] The seedling culture medium of the present invention includes rice straw fibers adsorbed with avermectin, which can simulate the root system of rice seedlings and absorb root secretions, attracting rice root-knot nematodes to actively approach. As a result, the nematodes attach to the rice straw fibers and come into contact with the avermectin agent. This not only greatly enhances the nematode-killing effect of avermectin but also attracts the rice root-knot nematodes, preventing them from finding the actual rice seedling roots and reducing their invasion and damage to the roots.

[0054] The seedling culture medium of the present invention includes amino oligosaccharide raw powder. The amino oligosaccharide plays the following roles: (1) It induces crops to produce chitinase, decomposes and absorbs chitosan oligosaccharides in nematodes and egg shells, dissolves the nematode body wall and egg shell, and thus causes the rice root-knot nematodes and eggs to die. The early and frequent use of amino oligosaccharides on crops can induce the number of chitinases to remain at a high level for a long time, thereby achieving the purpose of preventing nematodes. (2) After amino oligosaccharides are applied to the soil, a large number of beneficial bacteria such as actinomycetes can be cultivated in a short period of time. The large amount of antibiotic substances and resistance enzymes (chitinase, etc.) secreted by these beneficial bacteria can directly inhibit nematodes and eggs, and at the same time inhibit harmful bacteria such as Pythium, Phytophthora, Rhizoctonia, Fusarium oxysporum, mold, Fusarium, etc., thereby reducing the complex infection of harmful bacteria caused by nematodes. (3) Amino oligosaccharides have a strong rooting and root nourishing effect, promote the division of root cells, rapidly increase the number of capillary roots, reduce the occurrence of rotten roots, dead roots and rotten roots, and promote the development of the root system. Even if rice root-knot nematodes damage the root system, the root system can be restored to life and maintain normal growth, thus reducing the losses caused by the nematode damage.

[0055] The seedling culture medium of the present invention includes tea meal, also known as tea seed cake, which is a by-product left after oil is squeezed from tea fruit. It contains about 12wt.% of tea saponin (a mixture of pentacyclic triterpenoid saponins), has a good lethal effect on rice root-knot nematodes, and also has the function of high-end plant-based fertilizer.

[0056] The coating after soaking the seeds of the present invention is more effective than the coating of dry seeds in reducing the loss of effective ingredients and biocontrol bacteria, and the activity of the biocontrol bacteria is better maintained due to the fresh coating.

[0057] The seed coating of the present invention includes PDA potato dextrose agar culture media-mimicking ingredients: potato flour, glucose powder, and polyacrylamide. This series of components mimics PDA potato dextrose agar culture media, forming a fungal culture zone around the seed surface, allowing the fungus to expand around the seed, increasing its effective population and nematicidal activity.

[0058] The seed coating agent of the present invention includes glutinous rice flour, which serves as a dispersing and supplementing component of the coating agent and has viscosity, so that the coating component can be firmly attached to the surface of the rice seeds. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below in conjunction with specific examples, which are provided to explain the present invention rather than to limit it. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturer of the reagents or instruments is not specified, the products are conventional products that can be purchased commercially.

[0060] The Purpurogenum lilacinum described in the embodiment of the present invention is Nongxuwang brand, and the effective viable bacteria count is ≥200 million / g.

[0061] The fluopyram suspension concentrate described in the examples of the present invention has a brand name of "Lu Fu Da" and a fluopyram content of 41.7 wt.%.

[0062] The bast fiber membranes described in the embodiments of the present invention are commercially available products.

[0063] The avermectin emulsifiable concentrate described in the embodiment of the present invention is a commercially available product, and the avermectin content in the avermectin emulsifiable concentrate is 1.8 wt %, and is produced by Hebei Weiyuan Biochemical Co., Ltd.

[0064] The organic matter content of the plant nutrient soil described in the embodiment of the present invention is ≥30%.

[0065] The rice straw fibers described in the embodiments of the present invention have a fiber length of 0.8 to 1.2 cm.

[0066] Example 1

[0067] This embodiment discloses the composition and preparation method of the composition of the present invention.

[0068] The composition of the invention comprises a drug-carrying hemp fiber film for wrapping a rice seedling tray, a nematode-resistant rice seedling matrix and a rice seed coating agent.

[0069] 1. The preparation method of the drug-coated hemp fiber membrane comprises the following steps: soaking the hemp fiber membrane in a diluent containing a fluopyram suspension for 12 hours, taking it out, and air-drying it naturally.

[0070] The preparation method of the dilution containing the fluopyram suspension concentrate is as follows: take 0.2 ml of the fluopyram suspension concentrate, add water to 30 ml, and mix well.

[0071] A 60 cm x 60 cm hemp fiber membrane was soaked with 30 ml of a diluent containing a fluopyram suspension.

[0072] 2. The preparation method of the nematode-proof rice seedling substrate is as follows: the raw materials of the nematode-proof rice seedling substrate are uniformly mixed according to a proportion to obtain the nematode-proof rice seedling substrate.

[0073] The mass percentages of the raw materials of the nematode-proof rice seedling medium are: 40% biochar (15% walnut shell biochar + 25% coconut shell biochar), 2.5% mineral potassium humate, 20% plant nutrient soil, 5% perlite, 2.5% vermiculite, 20% rice straw fiber adsorbed with avermectin, 5% amino oligosaccharide raw powder, and 5% tea meal.

[0074] The preparation method of rice straw fiber adsorbed with avermectin is as follows: taking rice straw fiber, soaking it in a mixture of avermectin emulsifiable concentrate and water for 12 hours, taking it out, and air-drying it naturally;

[0075] The mixture of avermectin emulsifiable concentrate and water is prepared by mixing 15 ml of avermectin emulsifiable concentrate with 450 ml of water, wherein the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %.

[0076] The amount of the mixture of avermectin emulsifiable concentrate and water used for every 100g of rice straw fiber is 120ml.

[0077] 3. The preparation method of the rice seed coating agent is as follows: the raw materials of the rice seed coating agent are mixed uniformly according to a certain proportion to obtain the rice seed coating agent.

[0078] Calculated based on 1 kg of dry rice seeds, the rice seed coating agent includes 10 g of Pseudomonas lilacinus, 20 g of PDA potato dextrose agar medium biomimetic component, and 10 g of glutinous rice flour.

[0079] The mass ratio of the biomimetic components of the PDA potato glucose agar culture medium is: 60% potato flour, 35% glucose powder, and 5% polyacrylamide.

[0080] Example 2

[0081] This embodiment discloses the composition and preparation method of the composition of the present invention.

[0082] The composition of the invention comprises a drug-carrying hemp fiber film for wrapping a rice seedling tray, a nematode-resistant rice seedling matrix and a rice seed coating agent.

[0083] 1. The preparation method of the drug-coated hemp fiber membrane comprises the following steps: soaking the hemp fiber membrane in a diluent containing a fluopyram suspension for 0.5 hours, taking it out, and air-drying it naturally.

[0084] The preparation method of the dilution containing the fluopyram suspension concentrate is as follows: take 0.1 ml of the fluopyram suspension concentrate, add water to 20 ml, and mix well.

[0085] A 60 cm x 60 cm hemp fiber membrane was soaked with 20 ml of a diluent containing a fluopyram suspension.

[0086] 2. The preparation method of the nematode-proof rice seedling substrate is as follows: the raw materials of the nematode-proof rice seedling substrate are uniformly mixed according to a proportion to obtain the nematode-proof rice seedling substrate.

[0087] The mass percentages of the raw materials of the nematode-proof rice seedling medium are: 35% biochar (12% walnut shell biochar + 23% coconut shell biochar), 3% mineral potassium humate, 25% plant nutrient soil, 5% perlite, 2% vermiculite, 15% rice straw fiber adsorbed with avermectin, 8% amino oligosaccharide raw powder, and 7% tea meal.

[0088] The preparation method of rice straw fiber adsorbed with avermectin is as follows: taking rice straw fiber, soaking it in a mixture of avermectin emulsifiable concentrate and water for 0.5 hours, taking it out, and air-drying it naturally;

[0089] A mixture of avermectin emulsifiable concentrate and water is prepared by adding 450 ml of water to 10 ml of avermectin emulsifiable concentrate, wherein the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %.

[0090] The amount of the mixture of avermectin emulsifiable concentrate and water used for every 100g of rice straw fiber is 150ml.

[0091] 3. The preparation method of the rice seed coating agent is as follows: the raw materials of the rice seed coating agent are mixed uniformly according to a certain proportion to obtain the rice seed coating agent.

[0092] Calculated based on 1 kg of dry rice seeds, the rice seed coating agent includes 12 g of Pseudomonas lilacinus, 15 g of PDA potato dextrose agar medium biomimetic component, and 12 g of glutinous rice flour.

[0093] The mass ratio of the biomimetic components of the PDA potato glucose agar culture medium is: 65% of potato flour, 30% of glucose powder, and 5% of polyacrylamide.

[0094] Example 3

[0095] This embodiment discloses the composition and preparation method of the composition of the present invention.

[0096] The composition of the invention comprises a drug-carrying hemp fiber film for wrapping a rice seedling tray, a nematode-resistant rice seedling matrix and a rice seed coating agent.

[0097] 1. The preparation method of the drug-coated hemp fiber membrane comprises the following steps: soaking the hemp fiber membrane in a diluent containing a fluopyram suspension for 2 hours, taking it out, and air-drying it naturally.

[0098] The preparation method of the dilution containing the fluopyram suspension concentrate is as follows: take 0.4 ml of the fluopyram suspension concentrate, add water to 60 ml, and mix well.

[0099] A 60 cm x 60 cm hemp fiber membrane was soaked with 60 ml of a diluent containing a fluopyram suspension.

[0100] 2. The preparation method of the nematode-proof rice seedling substrate is as follows: the raw materials of the nematode-proof rice seedling substrate are uniformly mixed according to a proportion to obtain the nematode-proof rice seedling substrate.

[0101] The mass percentages of the raw materials of the nematode-proof rice seedling medium are: 45% biochar (18% walnut shell biochar + 27% coconut shell biochar), 3% mineral potassium humate, 15% plant nutrient soil, 3% perlite, 3% vermiculite, 25% rice straw fiber adsorbed with avermectin, 3% amino oligosaccharide raw powder, and 3% tea meal.

[0102] The preparation method of rice straw fiber adsorbed with avermectin is as follows: taking rice straw fiber, soaking it in a mixture of avermectin emulsifiable concentrate and water for 6 hours, taking it out, and naturally air-drying it;

[0103] The mixture of avermectin emulsifiable concentrate and water is prepared by mixing 20 ml of avermectin emulsifiable concentrate with 500 ml of water, wherein the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %;

[0104] The amount of the mixture of avermectin emulsifiable concentrate and water used for every 100g of rice straw fiber is 130ml.

[0105] 3. The preparation method of the rice seed coating agent is as follows: the raw materials of the rice seed coating agent are mixed uniformly according to a certain proportion to obtain the rice seed coating agent.

[0106] Calculated based on 1 kg of dry rice seeds, the rice seed coating agent includes 8 g of Pseudomonas lilacinus, 25 g of PDA potato dextrose agar medium biomimetic component, and 8 g of glutinous rice flour.

[0107] The mass ratio of the biomimetic components of the PDA potato glucose agar culture medium is: 55% of potato flour, 40% of glucose powder, and 5% of polyacrylamide.

[0108] Example 4

[0109] This embodiment discloses the composition and preparation method of the composition of the present invention.

[0110] The composition of the invention comprises a drug-carrying hemp fiber film for wrapping a rice seedling tray, a nematode-resistant rice seedling matrix and a rice seed coating agent.

[0111] 1. The preparation method of the drug-coated hemp fiber membrane comprises the following steps: soaking the hemp fiber membrane in a diluent containing a fluopyram suspension for 0.5 hours, taking it out, and air-drying it naturally.

[0112] The preparation method of the dilution containing the fluopyram suspension concentrate is as follows: take 0.5 ml of the fluopyram suspension concentrate, add water to 50 ml, and mix well.

[0113] A 60 cm x 60 cm hemp fiber membrane was soaked with 50 ml of a diluent containing a fluopyram suspension.

[0114] 2. The preparation method of the nematode-proof rice seedling substrate is as follows: the raw materials of the nematode-proof rice seedling substrate are uniformly mixed according to a proportion to obtain the nematode-proof rice seedling substrate.

[0115] The mass percentages of the raw materials of the nematode-proof rice seedling medium are: biochar 40% (walnut shell biochar 18% + coconut shell biochar 22%), mineral potassium humate 2%, plant nutrient soil 20%, perlite 8%, vermiculite 2%, rice straw fiber adsorbed with avermectin 17%, amino oligosaccharide raw powder 3%, and tea meal 8%.

[0116] The preparation method of rice straw fiber adsorbed with avermectin is as follows: taking rice straw fiber, soaking it in a mixture of avermectin emulsifiable concentrate and water for 8 hours, taking it out, and naturally air-drying it;

[0117] The mixture of avermectin emulsifiable concentrate and water is prepared by mixing 17 ml of avermectin emulsifiable concentrate with 420 ml of water, wherein the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %.

[0118] The amount of the mixture of avermectin emulsifiable concentrate and water used for every 100g of rice straw fiber is 140ml.

[0119] 3. The preparation method of the rice seed coating agent is as follows: the raw materials of the rice seed coating agent are mixed uniformly according to a certain proportion to obtain the rice seed coating agent.

[0120] Calculated based on 1 kg of dry rice seeds, the rice seed coating agent includes 8 g of Pseudomonas lilacinus, 20 g of biomimetic components of PDA potato dextrose agar medium, and 10 g of glutinous rice flour.

[0121] The mass ratio of the biomimetic components of the PDA potato glucose agar culture medium is: 58% potato flour, 34% glucose powder, and 8% polyacrylamide.

[0122] Example 5

[0123] This embodiment discloses the composition and preparation method of the composition of the present invention.

[0124] The composition of the invention comprises a drug-carrying hemp fiber film for wrapping a rice seedling tray, a nematode-resistant rice seedling matrix and a rice seed coating agent.

[0125] 1. The preparation method of the drug-coated hemp fiber membrane comprises the following steps: soaking the hemp fiber membrane in a diluent containing a fluopyram suspension for 0.5 hours, taking it out, and air-drying it naturally.

[0126] The preparation method of the dilution containing the fluopyram suspension concentrate is as follows: take 0.2 ml of the fluopyram suspension concentrate, add water to 15 ml, and mix well.

[0127] A 60 cm x 60 cm hemp fiber membrane was soaked with 15 ml of a diluent containing a fluopyram suspension.

[0128] 2. The preparation method of the nematode-proof rice seedling substrate is as follows: the raw materials of the nematode-proof rice seedling substrate are uniformly mixed according to a proportion to obtain the nematode-proof rice seedling substrate.

[0129] The mass percentages of the raw materials of the nematode-proof rice seedling medium are: biochar 40% (walnut shell biochar 12% + coconut shell biochar 28%), mineral potassium humate 3%, plant nutrient soil 15%, perlite 3%, vermiculite 2%, rice straw fiber adsorbed with avermectin 25%, amino oligosaccharide raw powder 8%, and tea meal 4%.

[0130] The preparation method of rice straw fiber adsorbed with avermectin is as follows: taking rice straw fiber, soaking it in a mixture of avermectin emulsifiable concentrate and water for 24 hours, taking it out, and air-drying it naturally;

[0131] The mixture of avermectin emulsifiable concentrate and water is prepared by mixing 12 ml of avermectin emulsifiable concentrate with 400 ml of water, wherein the concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %.

[0132] The amount of the mixture of avermectin emulsifiable concentrate and water used for every 100g of rice straw fiber is 150ml.

[0133] 3. The preparation method of the rice seed coating agent is as follows: the raw materials of the rice seed coating agent are mixed uniformly according to a certain proportion to obtain the rice seed coating agent.

[0134] Calculated based on 1 kg of dry rice seeds, the rice seed coating agent includes 10 g of Pseudomonas lilacinus, 15 g of PDA potato dextrose agar medium biomimetic component, and 12 g of glutinous rice flour.

[0135] The mass ratio of the biomimetic components of the PDA potato glucose agar culture medium is: 60% potato flour, 37% glucose powder, and 3% polyacrylamide.

[0136] Comparative Example 1

[0137] Compared with Example 1, this comparative example 1 does not contain the hemp fiber membrane with medicine.

[0138] Comparative Example 2

[0139] Compared with Example 1, in Comparative Example 2, the nematode-resistant rice seedling medium was replaced with a common seedling medium. The seedling medium in this comparative example was a rice machine-transplanted seedling medium of the brand name "Xiangzheng Agricultural Science", produced by Hunan Xianghui Agricultural Technology Development Co., Ltd.

[0140] Comparative Example 3

[0141] Compared with Example 1, this comparative example does not contain the rice seed coating agent.

[0142] Test Example 1

[0143] This test example discloses an experiment on using the composition of the present invention to control rice root-knot nematodes during the rice seedling stage.

[0144] Test rice: The rice variety is Sichuan Kang You Si Miao, bred by the Crop Research Institute of Sichuan Academy of Agricultural Sciences. The test site is located in Xigao Town, Guanghan City, Sichuan Province. Dryland seedlings are raised on light soil with medium fertility. In previous years, rice root-knot nematodes were more serious. The land was plowed and leveled on April 15, 2022. Each treatment had 10 seedling trays per replicate, with 4 replicates per treatment, arranged in random blocks. Seeds were soaked and germinated on April 22, with a sowing rate of 80g per seedling tray. During the trial, the paddy soil was kept moist, and water conservation was not required. Fertilization and pest and disease control were the same as other local farmland.

[0145] Conventional pesticide: 41.7% fluopyram suspension was sprayed on the soil three times in a row.

[0146] Thirty-five days after sowing, five-point sampling was used, with four plants sampled at each point, for a total of 20 rice plants and their rhizosphere soils per plot. The rice roots were washed and the number of root nodes in the rice root system was counted.

[0147] The experimental design included a total of 6 treatments (4 treatments + blank control + conventional drug control).

[0148] Table 1 Grouping table for the experiment on controlling rice root-knot nematodes during rice seedling stage

[0149]

[0150] The commercially available rice seedling raising substrate described in this test example is: a rice machine-transplanted seedling raising substrate with the brand name "Xiangzheng Agricultural Science", produced by Hunan Xianghui Agricultural Technology Development Co., Ltd.

[0151] 1. Treatment 1 Experimental operation: Coating rice seeds, wrapping rice seedling trays with medicated hemp fiber film, spreading rice seedling matrix on the rice seedling trays, and then evenly spreading the coated seeds in the seedling trays.

[0152] 1.1 Coating operation is:

[0153] (1) Seed soaking: Select seeds that are full and free of pests and diseases, remove impurities and broken seeds to ensure the purity and quality of the seeds, soak them in room temperature water for 12 hours, take them out and drain the water.

[0154] (2) Seed coating after soaking: Take a rice seed coating agent, add 5 times the amount of water to prepare a coating solution, use a rice coating machine to coat the soaked seeds, and place the coated rice seeds in a ventilated, cool and dry place. Based on 1 kg of dry rice seeds, the rice seed coating agent includes 10g of Pseudomonas lilacinus (effective viable count ≥ 200 million / g), 20g of PDA potato dextrose agar medium biomimetic component, and 10g of glutinous rice flour.

[0155] 1.2 The specific operation of wrapping the rice seedling tray with the medicated hemp fiber film in Treatment 1 is as follows: wrap the medicated hemp fiber film on a 60cm*25cm commercially available rice seedling tray, lay it flat and tighten it so that the hemp fiber film is close to the inside of the tray, and use cable ties to fix the fiber film at the eight top corners of the inner layer of the hole tray, so that the inner and outer layers of the bottom of the seedling tray are each covered with a layer of medicated hemp fiber film.

[0156] 1.3 The specific operation of using nematode-resistant rice seedling matrix for seedling cultivation in treatment group 1 was as follows: evenly spread 2 cm thick rice seedling matrix on the rice seedling tray wrapped with medicated hemp fiber film, and then evenly spread the soaked and coated seeds in the seedling tray and covered with a thin layer of soil.

[0157] 2. Experimental operation of treatment group 2: Compared with treatment group 1, treatment group 2 directly used rice seedling trays for seedling cultivation, and the rice seedling trays were not wrapped with any materials.

[0158] 3. Experimental operation of treatment group 3: Compared with treatment group 1, treatment group 3 adopts the composition of comparative example 2.

[0159] 4. Experimental operation of treatment group 4: Compared with treatment group 1, the rice seeds in treatment group 4 were not coated.

[0160] 5. Conventional control group operation: 41.7% fluopyram suspension was sprayed on the soil three times in a row: the test agent fluopyram suspension was diluted 1000 times at a dosage of 0.03 ml / seedling tray / time, and then sprayed on the soil on the day of sowing, 14 days after sowing, and 28 days after sowing.

[0161] 6. Experimental operation of blank control group: rice seedling trays were not wrapped with any materials, commercially available rice seedling substrate was used, and rice seeds were not coated.

[0162] The results are shown in the following table:

[0163] Table 2 Results of the experiment on controlling rice root-knot nematodes during the rice seedling stage

[0164]

[0165] Note: In this table, different letters a, b, c, d, and e indicate significant differences, P < 0.05.

[0166] The above results show that the horticultural traits (aboveground and underground parts) of rice seedlings treated with all the components of the composition of the present invention (the bottom of the rice seedling tray is wrapped with a hemp fiber film adsorbed with fluopyram, the seedling tray is applied with a nematode-proof rice seedling matrix, and the rice seeds are coated with biocontrol bacteria and the biomimetic components of the culture medium after soaking) all performed best, with the least number of root knots on the root system and the highest root knot inhibition rate. In addition, it can be seen that the root knot inhibition rate of the rice seedlings not coated with the hemp fiber film adsorbed with fluopyram is significantly lower than that of the rice seedlings not containing the nematode-proof seedling matrix and not coated with biocontrol bacteria, but is significantly higher than the conventional prevention and control methods and CK treatment. The above experimental data show that the three major components of the present invention are indispensable, and their organic combination and synergistic application can not only promote the healthy growth of rice seedlings, but also significantly reduce the infection of rice root-knot nematodes on the roots of rice seedlings. It is an effective method for preventing and controlling rice root-knot nematodes during the rice seedling stage.

[0167] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composition for controlling rice root-knot nematodes during the rice seedling stage, characterized in that: The invention is composed of a hemp fiber film with medicine for wrapping a rice seedling tray, a nematode-proof rice seedling matrix and a rice seed coating agent; The drug-carrying hemp fiber membrane is a hemp fiber membrane adsorbed with fluopyram; The nematode-proof rice seedling medium is composed of the following components in percentage by mass: 35-45% biochar, 2.0-3.0% mineral potassium humate, 15-25% plant nutrient soil, 3-8% perlite, 2.0-3.0% vermiculite, 15-25% rice straw fiber adsorbed with avermectin, 3-8% amino oligosaccharide raw powder, and 3-8% tea seed meal; The rice seed coating agent is used to coat soaked rice seeds. Calculated based on 1 kg of dry rice seeds, the composition of the rice seed coating agent is: 8-12 g of Pseudomonas lilacinus, 15-25 g of biomimetic components of PDA potato dextrose agar medium, and 8-12 g of a viscous dispersant. The PDA potato dextrose agar culture medium biomimetic component consists of the following components in percentage by mass: 55-65% potato flour, 30-40% glucose powder, and 3-8% polyacrylamide.

2. The composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 1, characterized in that: The nematode-proof rice seedling medium is composed of the following components in percentage by mass: 40% biochar, 2.5% mineral potassium humate, 20% plant nutrient soil, 5% perlite, 2.5% vermiculite, 20% rice straw fiber adsorbed with avermectin, 5% amino oligosaccharide raw powder, and 5% tea meal.

3. A composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 1 or 2, characterized in that: The preparation method of rice straw fiber adsorbed with avermectin comprises the following steps: soaking the rice straw fiber in a mixture of avermectin emulsifiable concentrate and water to fully soak the fiber, then taking it out and drying it in the shade; The length of rice straw fibers ranges from 0.8 to 1.2 cm; The mixture of avermectin emulsifiable concentrate and water is prepared by mixing 10-20 ml of avermectin emulsifiable concentrate with 400-500 ml of water. The concentration of avermectin in the avermectin emulsifiable concentrate is 1.8 wt %. For every 1 kg of rice straw fiber, use at least 1 kg of a mixture of avermectin emulsifiable concentrate and water.

4. A composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 1 or 2, characterized in that: Calculated based on 1 kg of dry rice seeds, the composition of the rice seed coating agent is: 10 g of Pseudomonas lilacinus, 20 g of PDA potato dextrose agar medium biomimetic component, and 10 g of a viscous dispersant.

5. The composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 4, characterized in that: The PDA potato dextrose agar culture medium biomimetic component consists of the following components in percentage by mass: 60% potato flour, 35% glucose powder, and 5% polyacrylamide.

6. A composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 1 or 2, characterized in that: The effective viable bacteria count of the purpurogenous fungus is ≥ 200 million / g; The viscous dispersant includes glutinous rice flour.

7. The method for preparing a composition for controlling rice root-knot nematodes during the rice seedling stage according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1. Prepare drug-coated hemp fiber membrane: soak the hemp fiber membrane in a diluted solution of fluopyram suspension, remove it, and air-dry it naturally; The diluent of the fluopyram suspension concentrate is 0.1-0.5 ml of fluopyram suspension concentrate diluted with water to 15-60 ml; A 60 cm × 60 cm hemp fiber membrane was evenly soaked with 15–60 ml of the diluted solution of fluopyram suspension; The content of fluopyram in the fluopyram suspension concentrate is 41.7%; Step 2. Prepare the nematode-resistant rice seedling medium: Mix the components of the nematode-resistant rice seedling medium evenly according to the proportions. Step 3. Prepare the rice seed coating agent: uniformly mix the components of the rice seed coating agent according to a certain proportion.

8. The method for preparing a composition for controlling rice root-knot nematodes during the rice seedling stage according to claim 7, characterized in that: A 60 cm × 60 cm hemp fiber membrane was evenly soaked with 30 ml of a dilution solution containing 0.2 ml of fluopyram suspension.

9. Use of the composition according to any one of claims 1 to 6 for controlling rice root-knot nematodes during the rice seedling stage.

10. A method for controlling rice root-knot nematodes during the rice seedling stage, characterized in that: The method is carried out using the composition according to any one of claims 1 to 6.

11. The method for controlling rice root-knot nematodes during the rice seedling stage according to claim 10, characterized in that: The method comprises the following steps: coating soaked rice seeds with the rice seed coating agent; growing rice seedlings with the coated seeds using a nematode-resistant rice seedling matrix; and covering the bottom and inner sides of the rice seedling tray with a layer of hemp fiber film with medicine.

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