Method for preventing and controlling diseases and insect pests in alfalfa field

Abstract

The invention belongs to the technical field of agricultural planting, and particularly relates to an alfalfa field disease and pest control method which comprises the following specific steps: before alfalfa seeds are planted, deeply ploughing soil by 30-50 cm, exposing the soil to the sun for 7-10 days, and cooperatively applying quick lime to kill grubs, cutworms and other underground insect eggs and root rot pathogenic bacteria in the soil; prevention and early monitoring before planting can avoid large-scale outbreak of diseases and insect pests, leaf gnawing, stalk rotting and root system damage are reduced, the yield of fresh grass is directly increased, and the yield can be increased by 15%-30%; physical and biological control reduces the use of chemical pesticides, avoids residual pollution, ensures the crude protein content of alfalfa, and reduces protein degradation caused by plant diseases and insect pests; disease control can avoid generation of pathogenic bacteria toxins, pest control can reduce fecula and honeydew pollution, and palatability is improved; crop rotation, deep ploughing and other measures reduce the cardinal number of diseases and pests, continuous cropping obstacles are avoided, and the yield stability of subsequent crops for rotation is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of agricultural planting technology, in particular to a method for preventing and treating diseases and pests in alfalfa field. BACKGROUND

[0002] Alfalfa is a high-quality legume forage originating from Iran, which is widely distributed all over the world. The life cycle of alfalfa varies under different conditions, generally 5-7 years, and can reach 25 years under some conditions. Alfalfa prefers warm and semi-arid climate, adapts to neutral and slightly acidic soil, and can grow in various soil types, and is suitable for growing in areas with annual precipitation of 250-800mm and long frost-free period, but not suitable for areas with high groundwater level, poor drainage or annual precipitation exceeding 1000mm. The nutritional composition of alfalfa is rich, including crude protein, minerals (without phytic acid phosphorus) and vitamins, and contains essential amino acids and trace elements required by animals. In addition, the root system of alfalfa is particularly developed, which can reach 10 meters deep into the ground, so it can effectively utilize the water in the lower layer of soil, which makes it perform well in the northern arid or semi-arid areas, with excellent drought resistance. At present, the planting area of alfalfa in North China is increasing; However, the effect of disease and pest control is limited in the process of alfalfa planting, and the growth process is easily disturbed by diseases and pests, which directly affects the yield and quality of alfalfa.

[0003] Therefore, the present application provides a method for preventing and treating diseases and pests in alfalfa field to solve the above problems. SUMMARY

[0004] The present application aims to provide a method for preventing and treating diseases and pests in alfalfa field to solve the problems in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for preventing and treating diseases and pests in alfalfa field, the specific steps of which are as follows: Step 1, prevention before planting: before planting alfalfa seeds, plow the soil to 30-50cm, expose to sunlight for 7-10 days, and apply lime to kill grubs, wireworms and other underground pest eggs and root rot pathogens; detect the pH of the soil, if the soil is acidic, apply lime to adjust the pH; if the soil is alkaline, apply organic fertilizer; Step two, growth period prevention and treatment: when the alfalfa grows and reaches the regreening period, observe the growth every 3-5 days, observe whether the leaves have the brown spore pile of rust, the yellow greenish spot of downy mildew, the curling or yellowing caused by the gathering of aphids / thrips; observe whether the stems have the holes caused by alfalfa armyworm larvae eating, the brown rot caused by stem blight; randomly dig 5-10 plants to observe whether the roots have the brown rot caused by root rot or the wounds caused by underground pests eating; set 5-10 monitoring points in the center and around the field, investigate the number of diseases and pests in 1 m2 of each point, record the disease degree, and start prevention and control when the prevention threshold is reached; The planting density is ensured to be about 250,000 plants per mu, the ventilation and light transmission are ensured, the field humidity is reduced, the base fertilizer is selected to be organic fertilizer, the amount applied is 2000 kg / mu, and the topdressing fertilizer is selected to be phosphorus and potassium fertilizer; drain water in time after rain to avoid water accumulation to induce root rot; Step three, disease and pest outbreak period prevention and treatment: physical prevention, biological prevention and chemical prevention are cooperated, the physical prevention selects to hang yellow board in the field to kill aphids and thrips; set 1 piece of frequency vibration type insecticidal lamp every 20 mu to kill alfalfa armyworm adults; the biological prevention selects to release ladybugs to control aphids, spray bacillus thuringiensis to control alfalfa armyworm larvae, and spray springomycin to control rust and downy mildew; apply trichoderma to control root rot; the chemical prevention is that triadimefon is used for rust, and metalaxyl is used for downy mildew, and they are mixed with water for spraying, the interval is 10 days, the safety interval is more than 14 days, imidacloprid is used for aphids and thrips, and phoxim granules are used for underground pests, the safety interval is more than 7 days; Step four, post-harvest prevention and treatment: after the last harvest, remove the residues and fallen leaves in the field, concentrate and burn or high-temperature compost, deep plough the soil, turn the surface layer of the soil into the deep layer, and destroy the overwintering environment of diseases and pests.

[0006] Preferably, in the step one, the amount of quicklime applied is 40-50 kg per mu.

[0007] Preferably, in the step one, when the soil pH is less than 6.0, it is determined to be acidic, and the soil pH is adjusted by quicklime; when the soil pH is greater than 8.5, it is determined to be alkaline, and organic fertilizer is applied.

[0008] Preferably, in the step two, the recorded disease degree includes disease leaf rate and insect density, and the prevention threshold is set to be that the aphid density is greater than 10 per plant, and the rust disease leaf rate is greater than 5%.

[0009] Preferably, in the step two, the phosphorus and potassium fertilizer includes superphosphate and potassium chloride, the amount of superphosphate is 30 kg per mu, and the amount of potassium chloride is 10 kg per mu.

[0010] Preferably, in the step three, the standard of the field yellow board is 20 pieces per mu; the standard of releasing ladybugs is 1000 per mu; the spraying amount of Bacillus thuringiensis is 200g per mu; the spraying amount of kasugamycin is 50ml per mu; the application amount of Trichoderma is 200g per mu; the application amount of trifloxystrobin is 50g per mu; the application amount of metalaxyl is 80g per mu; the application amount of imidacloprid is 10g per mu; and the application amount of phoxim granules is 2kg per mu.

[0011] Preferably, in the step four, the depth of deep ploughing soil is controlled to be 25-35cm.

[0012] Compared with the prior art, the method has the following beneficial effects: 1) Reducing biomass loss: The pre-planting prevention and early monitoring can avoid large-scale outbreak of diseases and pests, reduce leaf nibbling, stem rot, root damage, and directly improve fresh grass yield, which can increase yield by 15%-30%; 2) Improving nutritional and safety quality: Physical and biological control reduces the use of chemical pesticides, avoids residue pollution, ensures the crude protein content of alfalfa, reduces protein degradation caused by diseases and pests; controlling diseases can avoid the production of pathogen toxins, and pest control reduces feces and honeydew pollution, and improves palatability; 3) Maintaining long-term productivity: Rotation, deep ploughing and other measures reduce the base number of diseases and pests, avoid continuous cropping obstacles, and ensure the yield stability of subsequent crops. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The method is a flow chart. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0015] Embodiment: Please refer to Figure 1 The present application provides a technical solution: A method for controlling diseases and pests in an alfalfa field, and the specific steps of the method are as follows: Step 1: Pre-planting prevention and control: Before planting alfalfa seeds, deep plow the soil 30cm-50cm, expose it to the sun for 7-10 days, and apply quicklime to kill grubs, cutworms, and other underground pest eggs and root rot pathogens in the soil; test the soil pH. If the soil is acidic, apply quicklime to adjust the pH and inhibit the growth of root rot fungi; if the soil is alkaline, apply organic fertilizer; Avoid continuous cropping, which can easily lead to root rot and underground pest accumulation. Rotate crops with grasses (such as corn and wheat) for 2-3 years to break the cycle of pests and diseases. Crop rotation and soil treatment can destroy overwintering / oversummering sites for pests and diseases, reduce initial infection sources, avoid post-planting outbreaks of pests and diseases, and ensure seedling survival rates. Damage to seedlings during the seedling stage can directly lead to missing seedlings and broken ridges, reducing the number of plants per unit area. Step 2: Control during the growing season: When alfalfa is growing and reaching the greening stage, observe its growth every 3-5 days to see if there are yellow-brown spore piles of rust, yellow chlorotic spots of downy mildew, curling or loss of green leaves caused by aphids / thrips; observe the stems for holes caused by the gnawed larvae of the alfalfa armyworm, or browning and rot caused by stem blight; randomly dig up 5-10 plants and observe whether the roots are browning and rotted due to root rot, or wounds caused by underground pests; set up 5-10 monitoring points around and in the center of the field, investigate the number of pests and diseases within 1 square meter at each point, record the severity of the disease, and initiate control when the control threshold is reached; The planting density should be around 250,000 plants per mu (approximately 1.5 acres). Ensure good ventilation and light transmission, reduce field humidity, and use organic fertilizer as base fertilizer at a rate of 2,000 kg per mu. For topdressing, use phosphorus and potassium fertilizers, and avoid excessive nitrogen fertilizers (to prevent excessive plant growth and reduced resistance). Drain the water promptly after rain to prevent waterlogging that can cause root rot. Dynamic monitoring allows for timely intervention in the early stages of pest and disease outbreaks (before they spread on a large scale), preventing widespread leaf loss and photosynthesis, stem rot (causing lodging), or root damage (impacting nutrient absorption), thereby reducing biomass loss and increasing yield. It also prevents pest and disease secretions (such as aphid honeydew) or pathogen toxins from contaminating plants, ensuring quality. Step 3: Prevention and control during the outbreak period of pests and diseases: Through the coordination of physical control, biological control and chemical control, physical control uses yellow boards to lure and kill aphids and thrips in the field; set up one frequency-vibrating insecticidal lamp for every 20 mu to lure and kill adult insects such as alfalfa armyworm; biological control uses the release of ladybugs to control aphids, spraying Bacillus thuringiensis to control alfalfa armyworm larvae, spraying kasugamycin to control rust and downy mildew; root irrigation with Trichoderma to control root rot; chemical control is to use triadimefon for rust and metalaxyl for downy mildew, spraying with water, at intervals of 10 days, with a safe interval of more than 14 days, aphids and thrips with imidacloprid, and underground pests with phoxim granules mixed with soil and broadcast, with a safe interval of more than 7 days; Agricultural control enhances plant resistance by optimizing growth environment, reduces disease and pest susceptibility, ensures normal photosynthesis and nutrient accumulation, and improves yield; physical and biological control can reduce the use of chemical pesticides, avoid pesticide residue pollution of alfalfa, ensure the quality of forage such as palatability, nutritional value, and protect the ecological environment; chemical control can quickly control pests in emergencies and avoid large-scale spread of diseases and pests leading to reduced yield, such as reduced photosynthetic area and yield due to leaf consumption, and scientific use of pesticides can reduce residue risk.

[0016] Step four, post-harvest control: after the last harvest, remove the field residues, fallen leaves, and concentrate them for burning or high-temperature composting, deep plowing of the soil, and turning the surface layer of the soil into the deep layer to destroy the overwintering environment of diseases and pests.

[0017] In step one, the application amount of quicklime is 40-50 kg per mu; its effects are as follows: Precise killing of diseases and pests to avoid insufficient or excessive residues: the use of 40-50 kg / mu of quicklime can form a high alkaline environment in the soil, precisely killing soil grubs, wireworm eggs, and root rot pathogens (such as fusarium and pythium). At this dosage, alkaline substances can damage the eggshell structure of pest eggs and inhibit the germination of pathogen spores, while avoiding incomplete pest control due to insufficient dosage (such as less than 30 kg / mu), leaving a recurrence of diseases and pests; if the dosage of quicklime is too high (such as more than 60 kg / mu), it will cause the soil alkalinity to be too strong (pH>9 for a long time), disrupting the balance of soil microbial communities and affecting soil fertility; while the dosage of 40-50 kg / mu can gradually buffer the pH through subsequent planting and watering after completing pest control, avoiding long-term inhibition of alfalfa seed germination and root growth; Scientifically adjusting soil pH, taking into account improvement and crop adaptability: in step one, it is clear that "when the soil is slightly acidic, apply quicklime to adjust the pH", and the dosage of 40-50 kg / mu can adjust the pH to the appropriate range of 6.5-7.5 for most acidic alfalfa fields. This dosage can correct the toxicity of acidic soil to roots (excessive acidity can cause root rot), and avoid excessive alkalinity that affects the absorption of calcium, phosphorus, and other elements; Reduce costs and environmental burden, achieve economic and ecological synergy: excessive use of quicklime will increase planting costs, and excessive alkaline substances may pollute surrounding water bodies with rainwater infiltration; while the dosage of 40-50 kg / mu takes into account the economic and environmental aspects while ensuring control effectiveness, meeting the requirements of sustainable agriculture.

[0018] In step one, when the soil pH is less than 6.0, it is determined to be acidic and adjusted by quicklime, and when the soil pH is greater than 8.5, it is determined to be alkaline and organic fertilizer is applied; its effects are as follows: Accurate adaptation of alfalfa soil pH suitable range, to ensure crop growth vigor: the most suitable alfalfa growth in pH 6.5-7.5 neutral to slightly alkaline soil, when pH < 6.0, soil acidity is too strong will inhibit root development, reduce the ability to absorb water and nutrients, while it will increase the occurrence of root rot and other soil-borne diseases. At this time, use lime to adjust, can increase the pH to the appropriate range, restore root activity and enhance plant resistance. When pH > 8.5, the soil alkalinity is too strong to cause calcium, magnesium, phosphorus and other elements to be fixed, resulting in alfalfa deficiency symptoms, while the high alkaline environment will destroy the soil aggregate structure, leading to poor aeration, indirectly inducing diseases and pests. At this time, apply organic fertilizer, which can reduce alkalinity, improve soil structure, release fixed nutrients and ensure normal growth of alfalfa through the buffering effect of organic matter; Avoid soil ecological imbalance caused by blind adjustment, and strengthen the prevention and control of diseases and pests: If the determination standard of acid soil is too wide (such as pH < 6.5, adjust), it may lead to early or excessive application of lime, resulting in a sudden increase in soil pH, which will destroy the activity of beneficial microorganisms and weaken soil fertility and disease resistance. Limiting pH < 6.0 to adjust can ensure that intervention is only performed when acid soil has a significant negative impact on crops and disease prevention, avoiding excessive adjustment. If the alkalinity determination standard is too wide, it may blindly intervene in the case of light alkaline soil, leading to excessive organic fertilizer causing seedling burn or nutrient imbalance. Limiting pH > 8.5 to adjust can precisely improve the strong alkaline soil by using organic fertilizer to buffer the alkalinity of humus, improve soil water and nutrient retention capacity, and create favorable conditions for subsequent disease and pest control (such as reducing root diseases caused by soil compaction); Standardized operation process to improve prevention and control efficiency and stability: Clear pH determination threshold can reduce human error, allowing growers to quickly determine the adjustment measures through simple pH detection, avoiding operational confusion caused by ambiguous "acid / alkaline" definition. This standardized operation can ensure that the soil environment is always conducive to alfalfa growth and not conducive to the breeding of diseases and pests, reducing the risk of disease and pest outbreaks from the foundation, and ultimately achieving yield improvement and quality improvement through stable growth environment; In step two, the recorded disease incidence includes disease leaf rate and insect density, and the set control threshold is aphid insect density > 10 heads / plant and rust disease leaf rate > 5%; Its role is as follows: Accurate prevention and control to avoid blind use of pesticides: Clear quantitative indicators (such as "10 heads / plant" and "5% disease leaf rate") replace subjective judgments such as "obvious disease" and "more pests", which can accurately determine whether the disease and pest have reached the level that requires intervention. If the threshold is not met, chemical control or high-intensity intervention can be temporarily avoided to reduce pesticide misuse and waste of manpower and resources; If the threshold is exceeded, timely prevention and control can be performed to avoid the spread of diseases and pests; Protect the ecological balance in the field: when below the threshold, the number of pests and diseases is within the natural controllable range, and natural enemies such as ladybugs can play a natural regulatory role to maintain ecological balance. Avoiding early intervention to kill natural enemies, which may disrupt the ecological chain and make it more difficult to control subsequent pests and diseases (such as the secondary outbreak of aphids caused by the accidental killing of aphid natural enemies). Reduce costs and improve prevention and control efficiency: precise threshold setting can reduce unnecessary prevention and control operations (such as frequent pesticide spraying and natural enemy release), reduce pesticide and labor costs, and focus on intervention at key nodes when pests and diseases are about to break out, which can greatly improve prevention and control efficiency and avoid "small disease treatment" or "big disease misdiagnosis". Ensure alfalfa yield and quality: when the aphid population density is >10 per plant, the harm of sap sucking and virus transmission will significantly affect alfalfa growth (such as leaf curling and nutrient loss); when the rust leaf rate is >5%, the pathogen will spread rapidly, causing leaf yellowing and shedding, and photosynthesis will be inhibited.

[0019] In step two, the phosphorus and potassium fertilizers include superphosphate of lime and potassium chloride, the amount of superphosphate of lime is 30 kg / acre, and the amount of potassium chloride is 10 kg / acre; the functions are as follows: Enhance plant disease resistance and reduce the risk of disease and pest infection: the role of superphosphate of lime (phosphorus fertilizer): phosphorus fertilizer is a key element for alfalfa cell wall synthesis, nucleic acid metabolism, and energy transfer. The use of 30 kg / acre can ensure that the thickness of the plant cell wall increases, forming a physical barrier to reduce the piercing harm of piercing pests such as aphids and thrips, and inhibit the invasion of pathogens such as rust and stem rot. In addition, phosphorus fertilizer can promote root development and enhance resistance to root rot pathogens in the soil; The role of potassium chloride (potassium fertilizer): potassium fertilizer can increase the osmotic pressure of alfalfa cell sap, increase the toughness of leaves and stems, and increase the difficulty of pests such as aphids and alfalfa moths to feed (taste becomes hard), while promoting the synthesis of disease-resistant substances such as phenols and flavonoids in the plant body, and improving the resistance to rust and downy mildew. The use of 10 kg / acre can avoid the weak growth and poor resistance caused by insufficient potassium fertilizer, or the nutrient imbalance caused by excessive use (such as affecting the absorption of calcium and magnesium).

[0020] In step three, the standard for hanging yellow plates in the field is 20 per acre; the standard for releasing ladybugs is 1000 per acre; the spraying amount of Bacillus thuringiensis is 200 g / acre; the spraying amount of kasugamycin is 50 ml / acre; the application amount of Trichoderma is 200 g / acre; the application amount of triadimefon is 50 g / acre; the application amount of metalaxyl is 80 g / acre; the application amount of imidacloprid is 10 g / acre; the application amount of phoxim granules is 2 kg / acre.

[0021] In step four, the depth of deep plowing the soil is controlled at 25-35 cm; the functions are as follows: Precise destruction of overwintering environment of pests and diseases: Many pests and diseases (such as root rot pathogens, eggs or larvae of underground pests) will overwinter in the surface soil of alfalfa fields. Deep plowing to a depth of 25-35 cm can effectively turn the surface soil containing pathogens and pests into the deep layer, making these pests and diseases lose their suitable living environment, thereby reducing their overwintering survival rate and reducing the initial infestation source of pests and diseases in the next year; Balancing soil structure protection and operation efficiency: If the deep plowing is too shallow (less than 25 cm), it is difficult to turn the large amount of surface residues, fallen leaves and soil with pests and diseases into the deep layer, which cannot fully destroy the overwintering sites of pests and diseases, and the control effect will be greatly reduced. If the deep plowing is too deep (more than 35 cm), not only the energy consumption and cost of agricultural machinery operation will increase, but also the original soil aggregate structure may be damaged, leading to soil fertility decline and affecting the growth of subsequent alfalfa. The depth of 25-35 cm can balance the soil protection and operation efficiency while ensuring the control effect.

[0022] Example two: Summary of application effect test of comprehensive pest and disease control technology in alfalfa field I. Basic information of the test Test name: Effect of comprehensive pest and disease control technology in alfalfa field on yield and quality; Test site: Shunyi District, Beijing; Test variety: Wobuzi No. 2; II. Test design and method Test group: Use the "comprehensive pest and disease control method in alfalfa field" provided by the user, the specific measures are as follows: Step one, prevention before planting: Before planting alfalfa seeds, deep plow the soil to 30-50 cm, expose to sunlight for 7-10 days, and sprinkle with quicklime to kill soil grubs, ground beetles and other underground pest eggs and root rot pathogens; Test the acidity and alkalinity of the soil, if the soil is acidic, sprinkle quicklime to adjust the pH, if the soil is alkaline, apply organic fertilizer; Step two, control during growth period: Observe the growth every 3-5 days during the growth and regreening period of alfalfa, observe whether the leaves have rust disease spore piles, downy mildew yellow green spots, aphid / leafhopper aggregation leading to curling or loss of green; observe whether the stems have holes bitten by alfalfa armyworm larvae, brown rot caused by stem rot; randomly dig 5-10 plants and observe whether the roots have brown rot caused by root rot or wounds caused by underground pests; Set up 5-10 monitoring points around the field and in the center, investigate the number of pests and diseases in 1 square meter at each point, record the disease degree, and start control when the control threshold is reached; The planting density is guaranteed to be about 250,000 plants per mu, ensuring ventilation and light penetration, reducing field humidity, and using organic fertilizer for base fertilizer at a rate of 2000 kg / mu, and using phosphorus and potassium fertilizer for topdressing; drain water in time after rain to avoid water accumulation to induce root rot; Step three, disease and pest control: through physical control, biological control and chemical control, physical control selects yellow board hanging in the field to kill aphids and thrips; every 20 mu sets up 1 piece of frequency vibration type insecticidal lamp to kill adult alfalfa moth; biological control selects releasing ladybugs to control aphids, spraying bacillus thuringiensis to control alfalfa moth larvae, and spraying springomycin to control rust and downy mildew; root irrigation of trichoderma to control root rot; chemical control is rust with triadimefon and downy mildew with metalaxyl, mixed with water and sprayed, with a safety interval of 10 days and more than 14 days, aphids and thrips with imidacloprid, and subterranean pests with phoxim granules to mix soil and apply, with a safety interval of more than 7 days; Step four, post-harvest control: after the last harvest, remove the field residues and fallen leaves, concentrate on burning or high-temperature composting, deep ploughing the soil, turning the surface layer of the soil into the deep layer, and destroying the overwintering environment of diseases and pests; Control group: using local conventional control method (only spraying pesticide when disease and pest is obvious, without systematic deep ploughing, crop rotation and biological control); Test design: each group has 3 repetitions, with an area of 30 square meters, arranged randomly in groups, and the field management (except for disease and pest control) is consistent; Three, investigation content and method Yield index: Fresh grass yield: measure the fresh weight of each plot when harvesting, and convert it into yield per mu (kg / mu); Dry grass yield: take fresh grass samples to measure moisture content, calculate dry grass rate (dry grass weight / fresh grass weight x 100%), and then convert it into dry grass yield per mu; Growth traits: measure plant height (cm) and number of branches per plant, take 10 samples randomly from each plot, and take the average value.

[0023] Quality index: crude protein content: determined by Kjeldahl method; crude fiber content: determined by Van Slyke extraction method; sensory quality: observe leaf integrity (proportion of insect damage and disease spots), and stem color (whether yellowing).

[0024] Disease and pest occurrence: Incidence rate: disease leaf rate (%) = number of disease leaves / total number of leaves x 100%; Insect population decline rate: (insect population density before control-insect population density after control) / insect population density before control x 100%.

[0025] Four, test results and analysis Yield comparison:

[0026] Analysis: The fresh grass and dry grass yield per mu of the test group is significantly higher than that of the control group, with an increase of 31.7%. The reason is that the integrated control effectively controls the damage of rust (disease leaf rate <3% vs. 15% of the control group), aphids (insect density <5 heads / plant vs. 20 heads / plant of the control group), etc., reduces leaf abscission and stem decay, and at the same time promotes plant growth through reasonable water and fertilizer (phosphorus and potassium fertilizer), increases plant height and branch number, and more sufficient biomass accumulation.

[0027] Quality comparison:

[0028] Analysis: The test group has higher crude protein content, light disease and pest damage, and complete leaf retention (high photosynthetic efficiency and sufficient protein synthesis); the crude fiber content is reduced, and the palatability is better. The control group has damaged leaves due to insect damage and disease spots, resulting in loss of crude protein, and the plant increases the synthesis of crude fiber to resist diseases and pests, resulting in a decrease in quality; Disease and pest control effect: The test group has a disease incidence rate of rust and downy mildew reduced by more than 70% compared with the control group, and the insect population of aphids and alfalfa night moth is reduced by more than 90%, and the amount of chemical pesticides is reduced by 40% (the proportion of biological control and physical control is increased); Five, conclusion After using the "alfalfa field disease and pest integrated control method", the yield of fresh grass and dry grass is significantly improved (the increase is more than 30%), the plant height and branch number are obviously increased, mainly due to the systematic control of diseases and pests, the unimpeded growth of the plant, the great improvement of alfalfa quality, the increase of crude protein content, the decrease of crude fiber, the good integrity of leaves, and the higher safety due to the reduction of chemical pesticide use, which is more suitable for high-quality feed.

[0029] The method realizes the "yield and quality double improvement" through the whole process management of "prevention-monitoring-comprehensive control-post-production cleaning", which can efficiently control pests and promote plant healthy growth, and is suitable for popularization and application in alfalfa producing areas.

[0030] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. It is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any figure reference in the claims should not be regarded as limiting the claims involved.

[0031] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A method for controlling diseases and insect pests in alfalfa fields, characterized in that: The specific steps of the alfalfa field pest control method are as follows: Step 1: Pre-planting control: Before planting alfalfa seeds, deep plow the soil 30cm-50cm, expose it to the sun for 7-10 days, and apply quicklime to kill grubs, cutworms, and other underground pest eggs and root rot pathogens in the soil; test the soil pH. If the soil is acidic, apply quicklime to adjust the pH; if the soil is alkaline, apply organic fertilizer; Step 2: Control during the growing season: When alfalfa is growing and reaching the greening stage, observe its growth every 3-5 days to see if there are yellow-brown spore piles of rust, yellow chlorotic spots of downy mildew, curling or loss of green leaves caused by aphids / thrips; observe the stems for holes caused by the gnawed larvae of the alfalfa armyworm, or browning and rot caused by stem blight; randomly dig up 5-10 plants and observe whether the roots are browning and rotted due to root rot, or wounds caused by underground pests; set up 5-10 monitoring points around and in the center of the field, investigate the number of pests and diseases within 1 square meter at each point, record the severity of the disease, and initiate control when the control threshold is reached; The planting density should be around 250,000 plants per mu, ensuring good ventilation and light transmission, and reducing field humidity. Organic fertilizer should be used as base fertilizer at a rate of 2,000 kg per mu, and phosphorus and potassium fertilizers should be used as topdressing fertilizers. Drain the water promptly after rain to avoid waterlogging that may cause root rot. Step 3: Prevention and control during the outbreak period of pests and diseases: Through the coordination of physical control, biological control and chemical control, physical control uses yellow boards to lure and kill aphids and thrips in the field; set up one frequency-vibrating insecticidal lamp for every 20 mu to lure and kill adult insects such as alfalfa armyworm; biological control uses the release of ladybugs to control aphids, spraying Bacillus thuringiensis to control alfalfa armyworm larvae, spraying kasugamycin to control rust and downy mildew; root irrigation with Trichoderma to control root rot; chemical control is to use triadimefon for rust and metalaxyl for downy mildew, spraying with water, at intervals of 10 days, with a safe interval of more than 14 days, aphids and thrips with imidacloprid, and underground pests with phoxim granules mixed with soil and broadcast, with a safe interval of more than 7 days; Step 4. Post-harvest prevention and control: After the last harvest, remove the stumps and fallen leaves in the field, burn them or compost them at high temperature, plow the soil deeply, and turn the surface contaminated soil into the deep layer to destroy the overwintering environment of pests and diseases.

2. The method for controlling pests and diseases in alfalfa field according to claim 1, wherein: In the step 1, the amount of quicklime applied is 40-50 kg per mu.

3. The method for controlling pests and diseases in alfalfa field according to claim 1, wherein: In the step 1, when the soil pH is less than 6.0, it is determined to be acidic and is adjusted with quicklime. When the soil pH is greater than 8.5, it is determined to be alkaline and organic fertilizer is applied.

4. The method for controlling pests and diseases in alfalfa fields according to claim 1, wherein: In the step 2, the recorded disease severity includes the diseased leaf rate and insect population density, and the set control thresholds are aphid population density>10 heads / plant and rust diseased leaf rate>5%.

5. The method for controlling pests and diseases in alfalfa fields according to claim 1, wherein: In the step 2, the phosphorus and potassium fertilizers include superphosphate and potassium chloride, the amount of superphosphate used is 30kg / mu, and the amount of potassium chloride used is 10kg / mu.

6. The method for controlling pests and diseases in alfalfa fields according to claim 1, wherein: In the step three, the standard for hanging yellow boards in the field is 20 pieces / mu; the standard for releasing ladybugs is 1,000 per mu; the spraying amount of Bacillus thuringiensis is 200 g / mu; the spraying amount of kasugamycin is 50 ml / mu; the application amount of Trichoderma is 200 g / mu; the application amount of triadimefon is 50 g / mu; the application amount of metalaxyl is 80 g / mu; the application amount of imidacloprid is 10 g / mu; and the application amount of phoxim granules is 2 kg / mu.

7. The method for controlling pests and diseases in alfalfa fields according to claim 1, wherein: In the step 4, the depth of deep tillage of the soil is controlled to be 25-35 cm.

Images