Seed coating agent for controlling clubroot of rape suitable for cover cropping

Abstract

The present application relates to a seed coating agent for controlling rape root rot disease in the mode of straw returning and mulching planting, and belongs to the field of rape root rot disease control. The seed coating agent for controlling rape root rot disease in the mode of mulching planting comprises, by weight, 1-5 parts of cyazofamid, 1-3 parts of prochloraz, 6-10 parts of humic acid, 80-100 parts of an auxiliary agent, 0.2-1 parts of a soluble calcium salt, 0.1-0.5 parts of a water-soluble boron compound, and 1-3 parts of imidacloprid. The present application is suitable for controlling rape root rot disease in a shady and humid environment in the mode of straw returning and mulching planting, and can also inhibit weed growth, promote seedling growth, enable the seedlings to grow rapidly and break through the mulch, and increase yield.

Description

Technical Field

[0001] This invention belongs to the field of prevention and control of clubroot disease in rapeseed, and specifically relates to a seed coating agent suitable for preventing and controlling clubroot disease in rapeseed under straw return and straw mulch planting patterns. Background Technology

[0002] Seed coating is a seed treatment technology that uses adhesives or film-forming agents, along with specific seed coating machines or mixing methods, to coat non-seed materials such as fungicides, insecticides, micronutrients, plant growth regulators, colorants, or fillers onto the outside of the seed. This aims to achieve spherical seed shape or maintain the seed's original shape, improve stress and disease resistance, accelerate germination, promote seedling establishment, increase yield, and improve seed quality. The seed coating agent solidifies rapidly into a film, making it difficult to peel off. Seeds coated with this agent typically absorb water and swell quickly after sowing. As the embryo develops and the seedling grows, the various active ingredients in the seed coating agent are slowly released and absorbed by the seedling, or slowly released into the soil near or on the seed surface. This achieves the goals of preventing seedling diseases and pests, promoting crop growth and development, and increasing crop yield. Seed coating has been listed as a key agricultural technology project promoted in my country.

[0003] Clubroot disease of rapeseed is a soil-borne disease caused by *Platycorrhizalum brassicae*, whose dormant spores can survive in the soil for 5-20 years. When cruciferous plants are grown and soil conditions are conducive to disease development, clubroot disease can severely reduce rapeseed yields or even cause total crop failure, seriously threatening rapeseed production. Currently, the main control methods for rapeseed clubroot disease are chemical irrigation, crop rotation, and soil improvement. While soil improvement (such as the application of large amounts of lime) can be effective in controlling rapeseed clubroot disease, it can easily lead to soil compaction and reduced soil fertility. Crop rotation can be used to control rapeseed clubroot disease, but its effectiveness is poor because rotating different crops cannot eliminate the growth of large numbers of cruciferous weeds in dryland fields. Chemical control mainly involves spraying and drenching with chemical pesticides. In addition to soil treatment in the seedbed and root drenching during the seedling stage, chemical spraying also requires root drenching at transplanting and seedling drenching after survival to achieve better control results. At the same time, due to the large amount of pesticides used and the high risk of environmental pollution, long-term use of chemical pesticides not only causes soil pollution but also increases the health and safety risks to humans and animals. Most importantly, farmers are unwilling to accept chemical control because of the many treatment periods.

[0004] Currently, the relatively low organic matter content and acidic soil in most vegetable and rapeseed growing areas of my country are conducive to the occurrence of clubroot disease. In addition, heavy, moist, and poorly aerated soils are more susceptible to this disease; fields with low organic matter content, excessive application of chemical fertilizers, high groundwater levels, and poor drainage have a higher incidence rate and cause more severe damage.

[0005] More importantly, due to the unique mode and timing of infection of the clubroot pathogen in rapeseed, besides primarily entering and damaging the host plant through direct infection of the root hairs during the seedling stage, the fungus can also exacerbate the occurrence of clubroot disease by infecting seeds with dust or soil. In particular, once seeds are infected, the risk of clubroot disease in rapeseed increases significantly. Even if pesticides are sprayed later, they can only treat the symptoms, not prevent them, inevitably impacting rapeseed production.

[0006] In addition, for the straw return to the field or straw mulch planting of rapeseed, the straw is very easy to carry pathogens and the moist and shady soil environment after mulch planting can easily accelerate the reproduction of pathogens. At the same time, it also provides a more humid environment for clubroot pathogens in the soil to infect and cause disease. How to find a method that is suitable for straw mulch planting areas and can also effectively prevent and control rapeseed clubroot disease is an urgent problem to be solved. Summary of the Invention

[0007] In view of the shortcomings of existing rapeseed mulch planting models and the control technologies under these models, this invention provides a seed coating agent suitable for controlling rapeseed clubroot disease in mulch planting environments or regions. This seed coating agent can effectively inhibit the infection and damage of soil-borne diseases of rapeseed in the high-humidity environment after straw is returned to the field, promote seedling growth, and suppress weed growth.

[0008] The technical objective of this invention is achieved through the following technical solution: a seed coating agent suitable for controlling clubroot disease in rapeseed grown under cover grass, comprising, by weight:

[0009] 1-5 parts of cyazofamid, 1-3 parts of imazalil, 6-10 parts of humic acid, 80-100 parts of adjuvants, 0.2-1 parts of soluble calcium salt, 0.1-0.5 parts of water-soluble boron compound, and 1-3 parts of imidacloprid.

[0010] Furthermore, the additive is at least one of diatomaceous earth and kaolin.

[0011] Furthermore, the water-soluble boron compound is at least one of boron oxide, borax, and boric acid.

[0012] Furthermore, the soluble calcium salt is at least one of calcium nitrate and calcium oxide.

[0013] Furthermore, the dosage of the seed coating agent suitable for controlling clubroot disease in rapeseed plants is 20-40g per kilogram of rapeseed.

[0014] This invention also provides a method for using the above-mentioned seed coating agent suitable for controlling clubroot disease in rapeseed cultivation, comprising the following steps:

[0015] 1) Weigh the raw materials according to the proportions, mix them evenly, and obtain the coating agent mixture;

[0016] 2) Under stirring conditions, slowly add water to the coating agent mixture obtained in step 1), stir evenly, and then coat the rapeseed seeds.

[0017] Furthermore, the weight of water added in step 2) shall not exceed twice the weight of the coating agent mixture.

[0018] The present invention also provides a coated rapeseed obtained by the above-described method, wherein the coating thickness of the coated rapeseed is less than 0.1 mm.

[0019] The present invention also provides an application of the above-mentioned coated rapeseed seeds for the prevention and control of clubroot disease in rapeseed under the cover cropping model.

[0020] Furthermore, the application method involves evenly sowing the coated rapeseed seeds onto the straw. When manually sown directly onto the straw surface, the seeds will automatically sink through the gaps in the straw, but will not all come into contact with the surface soil, thus reducing the contact rate with pathogens.

[0021] Furthermore, the straw-covered planting mode is as follows: after the grain is harvested by machine, the straw is directly crushed and spread on the surface of the farmland. The preferred grain is rice. Because the rice straw covers the surface, weeds in the field are not easy to germinate and grow, the sown rapeseed seeds germinate quickly, and there are basically no wild rapeseed or other broadleaf weeds around the rapeseed seedlings, effectively reducing the number of weeds.

[0022] Among the existing methods for controlling clubroot disease in rapeseed, as recorded in "Research on Chemical Control Technology for Clubroot Disease in Rapeseed" and "Research on Occurrence Dynamics, Harm and Control Technology of Clubroot Disease in Rapeseed", the application of chemical agents is a relatively effective control method, but it requires the application of high doses and multiple applications of agents.

[0023] Furthermore, current methods for controlling clubroot disease, aside from seed disinfection, typically have a short effective period. When new clubroot pathogens are introduced into the planting area through seeds or other means, it often leads to a significant reduction in rapeseed yield. Repeated application of chemical agents after clubroot symptoms appear is essentially ineffective in curing the disease itself, increasing planting costs and failing to eliminate tumors in the root tissue. In particular, pesticide residues increase the harm to the soil and the potential threat to human and animal health.

[0024] The researchers of this invention discovered that calcium deficiency in soil, insufficient calcium oxide, and heavy clay soils all favor the occurrence of clubroot disease. Calcium salts can, to some extent, regulate soil pH and simultaneously increase the exchangeable calcium in the soil. 2+ The concentration of Ca can thus reduce the damage caused by clubroot. In addition, adding a certain concentration of Ca to the seed coating agent... 2+At this time, it is particularly important that the soil exchangeable calcium concentration is 1.21 × 10⁻⁶. -3 mol / Kg to 1×10 -2 At concentrations of mol / kg, it can stimulate and induce the germination of clubroot spores. Applying Ca in this range during the growth period of the previous crop's non-host plants... 2+ This method can promote the early germination of dormant spores of clubroot pathogens in the soil before the plant germinates. At this time, the spores die because they cannot find a cruciferous host after germination. This method can reduce the concentration of dormant spores of clubroot pathogens in the soil, effectively reduce the primary source of infection, and reduce the incidence of clubroot disease in subsequent cruciferous crops, thereby solving the problem of clubroot disease in cruciferous crops.

[0025] When rapeseed is directly sown and then covered with rice or other crop straw, the soil environment for the rapeseed seeds becomes one of high relative humidity and low light exposure. After being covered by straw, the rapeseed seeds are placed in a high-temperature, high-humidity environment, and in acidic soil, they are more susceptible to clubroot disease. Through extensive experimentation, the inventors of this invention discovered that cyazofamid, prochloraz, humic acid, and Ca... 2+ When used in combination with adjuvants, excellent control effects can be achieved against clubroot disease in rapeseed. As shown in the embodiments of this invention, the slow-release seed coating agent of this invention can achieve a control effect of over 90% against clubroot disease in rapeseed. Cyazofamid is a sulfadiazine fungicide, a protective fungicide, and has good effects against clubroot, downy mildew, and blight. Prochloraz is a broad-spectrum systemic fungicide, highly effective against fungi of the genera *Botrytis* and *Sclerotinia*, and can control gray mold and sclerotinia rot in fruit trees and vegetable crops. It is also effective against fungi resistant to benzimidazole. It has significant control effects against diseases caused by various ascomycetes and deuteromycetes in crops, especially against sclerotinia rot in rapeseed cultivation. It provides good protection and has a long-lasting effect, preventing the development and spread of lesions. Satisfactory results can be achieved when used before or at the early stage of crop disease. It is worth mentioning that even if clubroot pathogens are artificially added 4-8 weeks later, the control effect of this invention is not affected. This is a significant improvement over conventional methods, which can only control clubroot for 2-4 weeks and require larger dosages. This is mainly due to the early application of protective agents such as cyazofamid and prochloraz to the seed surface, allowing them to enter the soil before the seeds germinate and form root hairs. This prevents clubroot pathogens near the seeds from infecting the germinating root hairs. By establishing an effective control method targeting the root hair infection pathway of clubroot pathogens during the seedling stage (clumproot pathogens mainly invade through the root hairs or young roots of rapeseed seedlings), this invention not only develops a certain level of resistance in the root hairs but also effectively prolongs the residence and action time of clubroot control agents on the rapeseed roots through the combined effect of increasing agent adhesion and reducing the ability of rainwater to wash away the agents by using mulch. This significantly improves the control effect of clubroot and makes a major contribution to completely eliminating the threat of clubroot to rapeseed cultivation.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. It can achieve a 90% control effect on clubroot disease in rapeseed under the special planting mode of shady, humid and high temperature environment with straw cover planting.

[0028] 2. Promote the healthy growth of seedlings so that they can grow tall and break through the covering grass, thus preventing yellowing of seedlings and affecting yield.

[0029] 3. While the seedlings grow healthily, they can suppress the growth of weeds. Attached Figure Description

[0030] Figure 1 The seedling emergence period for the control group planted with rapeseed seeds;

[0031] Figure 2 This refers to the germination period of rapeseed seeds planted in Example 1; Figure 1 and Figure 2 Filmed during the same period;

[0032] Figure 3 The growth of rapeseed seedlings in the control group after germination;

[0033] Figure 4 This is a description of the growth of rapeseed seedlings after germination in Example 1. Figure 3 and Figure 4 Shot at the same time, it can be seen that Figure 4 The rapeseed seedlings are growing normally. Figure 3 Rapeseed seedlings with diseased cotyledons have poor germination rates.

[0034] Figure 5 for Figure 3 The roots of the rapeseed seedlings show obvious signs of clubroot disease.

[0035] Figure 6 for Figure 4 The roots of the rapeseed seedlings; one can see Figure 6 The roots of the rapeseed seedlings grew and developed well, and there was no clubroot disease.

[0036] Figure 7 This is the growth of rapeseed in the control group; it can be seen that the rapeseed growth is uneven, and there are many weeds nearby that are growing vigorously.

[0037] Figure 8 This is the rapeseed growth situation in Example 1; it can be seen that there are very few weeds near the rapeseed and their growth is weak. Detailed Implementation

[0038] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0039] Experimental conditions: The following examples and control examples were conducted in the rice-oilseed rotation field of Longteng Agricultural Machinery Professional Cooperative, Longquan Village, Xiushui Town, Anzhou District, Mianyang City. The seed sowing method was as follows: after the mechanized harvesting of rice, the crushed straw was manually spread on the ground surface, and in mid-October 2020, rapeseed seeds were manually and evenly sown on the straw. The seed sowing rate was 300 grams per 667 square meters.

[0040] Example 1

[0041] A seed coating agent suitable for controlling clubroot disease in rapeseed grown under mulch is prepared by the following method:

[0042] 1) By weight, prepare 1 part of cyazofamid, 1 part of prochloraz, 6 parts of humic acid, 80 parts of adjuvants, 0.2 parts of soluble calcium salt, 0.1 parts of water-soluble boron compound and 1 part of imidacloprid, mix them evenly to obtain the coating agent mixture.

[0043] 2) Under stirring conditions, water is slowly added to the coating agent mixture obtained in step 1), and the mixture is stirred evenly to coat the rapeseed seeds; the mass ratio of water to the coating agent mixture is 2:1.

[0044] Example 2

[0045] A seed coating agent suitable for controlling clubroot disease in rapeseed grown under mulch is prepared by the following method:

[0046] 1) By weight, prepare 5 parts of cyazofamid, 3 parts of prochloraz, 10 parts of humic acid, 100 parts of adjuvant, 1 part of soluble calcium salt, 0.5 parts of water-soluble boron compound and 3 parts of imidacloprid, mix them evenly to obtain the coating agent mixture.

[0047] 2) Under stirring conditions, water is slowly added to the coating agent mixture obtained in step 1), and the mixture is stirred evenly to coat the rapeseed seeds; the mass ratio of water to coating agent mixture is 1.8:1.

[0048] Example 3

[0049] A seed coating agent suitable for controlling clubroot disease in rapeseed grown under mulch is prepared by the following method:

[0050] 1) By weight, prepare 3 parts of cyazofamid, 1 part of prochloraz, 8 parts of humic acid, 85 parts of adjuvants, 0.4 parts of soluble calcium salt, 0.2 parts of water-soluble boron compound and 2 parts of imidacloprid, mix them evenly to obtain the coating agent mixture.

[0051] 2) Under stirring conditions, water is slowly added to the coating agent mixture obtained in step 1), and the mixture is stirred evenly to coat the rapeseed seeds; the mass ratio of water to the coating agent mixture is 2:1.

[0052] Compare with Example 1

[0053] Except for the absence of cypermethrin, the rest is the same as in Example 1.

[0054] Compare with Example 2

[0055] Except for the absence of imazalil, the rest is the same as in Example 1.

[0056] Rapeseeds treated with the coating agents of Examples 1-3 and Control Examples 1 and 2 were used as the experimental group; the blank group consisted of rapeseed without any treatment. The control effect (cluster rot incidence) and yield results are shown in Table 1:

[0057] Table 1

[0058] Number of seedlings per square meter Plant survival rate (%) Yield (kg / mu) Example 1 33.6 92.6 161 Example 2 33.3 93.3 163 Example 3 34.0 93.6 162 Compare with Example 1 29.3 80.0 156 Compare with Example 2 28.3 74.6 152 Blank group 25.6 69.6 106

[0059] As shown in Table 1, it can be seen that the coated seeds provided by the present invention can achieve a control effect of up to 90% against clubroot disease in rapeseed, while also promoting seedling emergence and increasing yield.

[0060] Referring to the accompanying drawings, there was no significant difference in the germination speed of the seeds in the examples, comparative examples, and control group. After germination, the two cotyledons of the coated seeds prepared in the examples grew upwards quickly and basically did not die before the formation of true leaves. After germination, many seeds in the comparative examples and control group began to show diseases in the cotyledons or hypocotyls after emergence and gradually died, resulting in a significant decrease in the seedling rate. Relatively speaking, the seeds in the comparative examples and control group were still worse in terms of later growth and development and vigor, but the effect of the comparative examples was slightly better than that of the control group.

[0061] Furthermore, it should be emphasized that the coated seeds in this embodiment can effectively suppress weed growth. Specifically, because rice straw covers the ground during mulch cultivation, weeds in the soil are less likely to germinate and grow. The coated seeds in this embodiment can grow rapidly, and their growth advantage inhibits the growth of wild rapeseed and other weeds, resulting in virtually no wild rapeseed or other broadleaf weeds around the rapeseed seedlings, effectively reducing the number of weeds.

[0062] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A seed coating agent for controlling clubroot of oilseed rape suitable for cover cropping, characterized in that, By weight parts comprising: Cyazofamid 1-5 parts, prochloraz 1-3 parts, humic acid 6-10 parts, adjuvant 80-100 parts, soluble calcium salt 0.2-1 part, water-soluble boron compound 0.1-0.5 part and imidacloprid 1-3 parts.

2. The coating agent for controlling clubroot of rape for cover crop planting according to claim 1, characterized by, The adjuvant is at least one of diatomite and kaolin.

3. The coating agent for controlling clubroot of rape suitable for cover crop planting according to claim 1, characterized by, The water-soluble boron compound is at least one of boron oxide, borax and boric acid.

4. The coating agent for controlling clubroot of rape suitable for cover crop planting according to claim 1, characterized by, The soluble calcium salt is at least one of calcium nitrate and calcium oxide.

5. The coating agent for controlling clubroot of rape for cover crop planting according to any one of claims 1 to 4, characterized by, The dosage of the seed coating agent for controlling clubroot of oilseed rape suitable for no-tillage planting is 20-40 g per kilogram of oilseed rape seeds.

6. The method of using a seed coating for the control of clubroot of crucifers suitable for cover cropping according to any one of claims 1 to 5, characterized in that, Comprising the following steps: 1) Weighing raw materials according to the ratio, mixing uniformly to prepare coating agent mixture; 2) Under stirring, slowly adding water to the coating agent mixture obtained in step 1), stirring uniformly, and coating on oilseed rape seeds.

7. The method of use of claim 6, wherein, The weight of water added in step 2) is not more than 2 times the weight of the coating agent mixture.

8. The use of the seed coating agent for controlling clubroot of oilseed rape according to claim 1 for controlling clubroot of oilseed rape in no-tillage planting mode.

9. Use according to claim 8, characterized in that, The method of the use is that the oilseed rape seeds coated with the seed coating agent for controlling clubroot of oilseed rape are evenly spread on the straw.

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