CN114902903B - Green prevention and control method for lemon round spot - Google Patents

Abstract

The invention discloses a green prevention and control method for lemon round spot, which belongs to the technical field of prevention and control for the lemon round spot and comprises the following steps: s1, reasonably fertilizing and cultivating the tree vigor; s2, reasonably trimming and keeping the new shoots; s3, reasonably loading and timely harvesting; s4, thoroughly cleaning the garden comprehensively; s5, precise chemical prevention and treatment. The invention improves the soil fertility by reasonable fertilization, strengthens the tree vigor, enhances the cold resistance and the disease and pest resistance of the tree body, ensures proper planting density by reasonable pruning, has good ventilation and light transmission of the tree crowns, reduces disease occurrence, reduces the burden of the tree body by reasonable load and timely harvesting, avoids providing favorable conditions for pathogen infection, thoroughly and thoroughly clears the garden in winter, spring and each time of tip drawing, reduces the disease base number of the coming year, reduces the severity of disease in the coming year, and can effectively prevent and control the lemon round spot by combining with accurate chemical control.

Description

Green prevention and control method for lemon round spot

Technical Field

The invention relates to the technical field of prevention and control of lemon round spot, in particular to a green prevention and control method of lemon round spot.

Background

The lemon round spot is a new fungal disease in lemon producing area, is a low-temperature infection disease, and is usually infected in early winter and spring to damage lemon leaves, branch tips and fruits. Symptoms begin to appear in the middle ten days of 12 months and become worse gradually, the disease peak is from the last 2 months to the middle ten days of 3 months, and the disease leaves basically fall off in the last 3 months. The disease is the heaviest in the early winter and spring, and the disease is not usually generated in the high-temperature season. The method is also called as a destructive disease because of quick spread, serious harm, more damage to lemon varieties and difficult prevention and control, and huge economic loss is easily caused to lemon growers.

In recent years, the lemon round spot disease occurs more frequently in China, and in Chongqing Wanzhou in the abdomen-heart city of three gorges reservoir area, the lemon is generally damaged by the round spot disease, and the disease area is from 8000 mu in 2019 to nearly 10 ten thousand mu in 2022. Once the lemon round spot disease occurs, the leaf spots on the leaf surfaces of the branches and the leaves, a large number of fallen fruits and even absolute production are caused, and the yield and the quality of the lemon are threatened. According to the previous research, the spreading of the lemon round spot disease is mainly based on wind and rain, and the influence of wounds, insect pests and the like is small, so that the prevention and treatment of the round spot disease mainly surrounds the two main parts of cutting off a spreading chain for reducing the spreading adverse factors of the wind and rain, preventing infection and timely preventing and treating after the infection. Flowers or fruits are arranged on the annual tree of the lemon, the flowers and fruits are not arranged in 12-3 months except for the most serious disease occurrence in the whole year, and the rest time is represented by the same flower and fruit tree, so that the method has extremely high requirements on the disease prevention and control technology of the round spot disease. Because the occurrence time of the round spot disease and other fungi is different in occurrence severity, the round spot disease belongs to new diseases, and the related prevention and control experience is lacking. At present, the resistance identification of the lemon round spot is not provided with a set of perfect and feasible prevention and control technical system, which also causes the disease of the lemon round spot to be destructive hazard, has very little prevention and control effect and has slow breeding process of disease-resistant varieties.

Therefore, through research, tracking and experimental study in 2019, according to the occurrence condition of the lemon leaf spot in the area of Chongqing in Wanzhou, a green prevention and control method for the lemon leaf spot is developed, and the lemon leaf spot can be effectively prevented and controlled.

Disclosure of Invention

The invention aims to provide a green prevention and control method for lemon round spot so as to realize effective prevention and control of the lemon round spot.

In order to achieve the above purpose, the present invention provides the following technical solutions:

a green prevention and control method for lemon round spot comprises the following steps:

s1, reasonably fertilizing and cultivating the tree vigor: applying 2 jin of high nitrogen sprouting fertilizer per plant for 2-3 months, and additionally spraying leaf fertilizer and brassin for 1 time; applying 2 jin of fruit strengthening fertilizer per plant in the last ten days of 6 months, and spraying foliar fertilizer for 1 time; applying 1.0-1.5 jin of still positive fertilizer after each batch of fruit picking after 8 months; applying 5 jin/plant of organic fertilizer for 9-10 months, and spraying foliar fertilizer for 1 time; 1 time of fruit picking fertilizer 1.5 jin/plant is added after pruning for 11-12 months, and brassin and foliar fertilizer are sprayed for 1-2 times;

s2, reasonably trimming, and guaranteeing new tips: adopting a natural open heart tree shape, and cutting, thinning, retracting and sawing big branches of a fruiting tree from the time of fruit picking in winter to the time of sprouting in spring in the next year; the proportion of spring tips to flower buds and young fruits is regulated by partially overlapping and crossing branches through short cuts in spring; in summer, bud picking, tip placing and core picking are carried out on the young tree, flower buds and young fruits are removed in time, xia Shao is carried out on the adult fruit tree, and excessive flower branches are removed; erasing scattered early autumn tips in autumn and carrying out trunk girdling, putting the early autumn tips in 8 months in the middle and late days, picking the core when the early autumn tips grow to 6-8 leaves, and erasing late autumn tips sprouting after 9 months in the middle;

s3, reasonable load and timely harvesting: removing residual fruits, undersize fruits and top fruits before bagging, controlling the fruit retention amount to be about 2000 kg/mu, wherein the fruit retention part is suitable for the inner chamber and the middle lower part of the tree body; harvesting each batch of fruits in time, and finishing harvesting in the middle ten days of 11 months;

s4, comprehensively and thoroughly cleaning a garden: spraying 25% prochloraz 1500 times liquid in whole garden in the middle and upper 11 months after fruit picking, and spraying one-time Baume 1 degree lime sulfur or 0.5% -0.8% Baume liquid in whole garden after extreme low temperature in winter to realize winter garden cleaning; spraying 40% of tebuconazole and prochloraz 800 times or 97% of mineral oil 150-200 times or 40% of pyridaben and etoxazole 5000 times or 22.4% of spirotetramat 5000 times compound medicine in middle ten days to realize garden cleaning in spring;

s5, precise chemical prevention and treatment: 25% of silazol, prochloraz or 40% of penconazole, prochloraz or 2% of amino oligosaccharin plus 0.5% of urea or 60% of benzol, propiconazole or 30% of difenoconazole or 45% of prochloraz or 3% of Zhongshengmycin or 40% of pyraclostrobin, and difenoconazole are sprayed on tree crowns, tree trunks and the ground for 1 time respectively in the middle and the last ten days of 3 months and before flowers, and in the summer of 5-6 months and in the autumn of 7-8 months. For orchards with serious disease, after 11-12 months fruit picking and before low temperature comes, the preparation is sprayed once again before the orchards are cleaned in winter.

Further, the step S1 further includes: 10 months to 12 months, spraying Shi Shuguan with 2 permillage urea, 2 permillage potassium dihydrogen phosphate, 2000 times calcium magnesium boron and 1500 times brassinolide for one time, spraying for 10-15 days, and continuously spraying for 2-3 times, and mulching.

Further, applying fruit-strengthening fertilizer 3-5 days before spraying fruit-protecting agent and insecticidal bactericide, spraying fruit-protecting agent and insecticidal bactericide when the diameter of the fruit is about 40mm, and bagging after the sprayed agent and dew are dried.

Further, the step S4 further includes: scraping off the lesions, moss and cocked skin on the trunk and the main branch, and then mixing 10 parts of quicklime, 2 parts of lime-sulfur mixture, 1 part of salt and 10 parts of clear water to obtain pasty liquid for whitening the trunk.

Further, the step S4 further includes: after fruit picking in winter and before germination, and before each new shoot extraction, the secondary fruit, the diseased leaf and the diseased branch of the tree are cut off in time, and the dead branch, the fallen leaf, the rotten fruit and the dead branch in the garden are removed, and are buried deeply or burnt intensively.

The beneficial effects of the invention are as follows:

by reasonable fertilization and balanced nutrition, the invention improves soil fertility, strengthens tree vigor, and enhances the cold resistance and insect resistance of the tree body; the young shoots are well protected through reasonable pruning, so that the planting density is proper, the ventilation and light transmission of the crowns are good, and the internal and external flowering and layering three-dimensional results are achieved, so that the occurrence of diseases is reduced; by reasonable load and timely harvesting, the tree body burden is reduced, and favorable conditions for pathogen infection are avoided; the disease severity in the next year is reduced by comprehensively and thoroughly cleaning the garden, and reducing the bacterial cardinality in the next year; chemical control is performed timely according to high-temperature and high-humidity climates in the three gorges reservoir area, different tip drawing periods and result characteristics of the lemon, so that a good control effect is achieved, and the chemical control effect is further improved through alternate rotation and compound medication.

Drawings

Fig. 1 is a flowchart of a green prevention and control method for lemon round spot according to an embodiment of the present invention;

FIG. 2 is a diagram showing lemon fruit at the onset of round spot;

FIG. 3 is a view showing the serious defoliation of fruit trees in the incidence of round spot disease;

FIG. 4 is a view showing the tips of fruit tree branches at the time of onset of round spot.

Detailed Description

The invention is described in further detail below with reference to the attached drawings and embodiments:

analysis of cause of disease of round spot

1. Variety resistance

Resistance differences between different citrus varieties. The current disease-causing varieties mainly comprise Xingjin, gong Chuan, wenzhou mandarin orange, kumquat, you Like mandarin orange, vone segment navel orange, granulated sugar orange, beijing orange and other varieties, the early disease resistance identification proves that 091 is free of citrus fruits and other miscellaneous citrus fruits are relatively most susceptible to diseases, the resistance of oranges, tangerines and tangerines is inferior, and the resistance of the shaddock varieties is strongest.

2. Geographical climate conditions

According to investigation, the first place where citrus round spot occurs, such as urban solid county of Shanxi is a periodical ice and snow disaster and frost serious area, and the Chongqing Wanzhou white sheep town is that in winter, although there is no serious frost, the duration of bright frost is long. Therefore, low temperature locations such as windward slopes at elevations of 500 meters or more, valley depressions, paddy fields and tuyere locations, or cold damage due to low temperature wind damage are the main causes of serious wheel spotting.

3. Mismanagement of

Excessive load, improper wet damage and fertilization, neglecting the protection of the young shoots and cleaning the garden, and causing serious occurrence of the lemon round spot.

And (II) a round spot disease prevention and control method:

s1, reasonably fertilizing and cultivating and strengthening tree vigor

By investigation and analysis of the fertilization conditions of lemon gardens with different tree vigor, the lemon round spot disease belongs to weak parasitic bacteria like anthracnose, and can only happen greatly under the condition of debilitation of lemon trees. 2019. 2021 is light in winter frost, most of lemon gardens with serious morbidity are farmer pipe-loss orchards, the tree vigor is serious, the orchards of enterprises with good management are strong, and the morbidity is relatively light. Farmers lose the pipe orchard, the nitrogen fertilizer is excessively applied, the organic fertilizer is less in dosage, the phosphorus-potassium fertilizer is insufficient in dosage, and the nutrient proportion is seriously disregulated, so that branches grow vigorously, branch tips and leaves develop inadequately and inadequately, and a large number of favorable conditions are provided for invasion hazard of alternaria.

The organic matters of the soil are increased, the balanced application of nitrogen, phosphorus and potassium fertilizers and trace element fertilizers is emphasized, the soil is loosened, the nutrition is balanced, and the soil fertility is improved. Applying 2 jin of high nitrogen (nitrogen content is more than or equal to 20%) sprout fertilizer for 2-3 months, and supplementing leaf fertilizer and brassin containing boron, zinc, magnesium and other medium trace elements for 1 time; applying 2 jin of strong fruit fertilizer (the potassium content is more than or equal to 20 percent) per plant in 6 to 7 months, and spraying foliar fertilizer containing potassium, magnesium and zinc elements on the leaf surface for 1 time; applying 5 jin/plant of organic fertilizer for 9-10 months, and spraying foliar fertilizer containing phosphorus, potassium, boron, zinc and magnesium elements for 1 time; after pruning for 11-12 months, 1 time of sun-returning fertilizer (low-nitrogen high-phosphorus potassium fertilizer) 1.5 jin/plant is added, and brassin and leaf fertilizer containing boron, zinc and magnesium elements are sprayed for 1-2 times.

Aiming at the current high-incidence situation of the ten thousand state lemon round spot, large-area branches and leaves are withered and fallen, even dead trees are caused, and the method is characterized in that 2 permillage urea, 2 permillage of dihydrogen phosphate, 2000 times of potassium, calcium, magnesium and boron and a certain proportion of plant growth regulators such as brassin are sprayed for Shi Shuguan and 10-15 days for one time before winter of 10 months (before and after fruit picking) to 12 months in the same year, and the spraying is carried out for 2-3 times continuously. The plant mulching and the pest control are enhanced in winter, the blade resistance is improved, and the morbidity and fallen leaves can be effectively reduced.

1. Experimental protocol

2021-2022, in the area of the disease of the white sheep town Bai Yancun in the Wanzhou area of Chongqing, three consecutive years, a winter leaf-protecting test was carried out, and the period of time for spraying the medicine and the climate are shown in the following table one within 7 hours after the medicine is applied.

List one

The pesticide application adopts a 3WBD-16HBA type backpack electric sprayer of Taizhou city road-bridge Fuda sprayer factory, double hollow cone spray heads are used for operation, the spraying liquid amount is 50 kg/treatment until the inside and outside of the tree crowns are uniformly sprayed, 3 trees are treated each, 3 repeats are arranged, and 9 trees are treated each. Each cell is randomly distributed. Lemon is in the lowest temperature period of ten thousand states at the time of administration and begins to appear with round spots and fallen leaves. During the test, the test area was cleared in winter and a lime sulfur mixture was applied once.

Treatment 1: crown is sprayed with 2 permillage urea, 2 permillage monopotassium phosphate and 1500 times brassinolide for 10-15 days before winter (before and after fruit picking) to 12 months, and the crown is sprayed for 10-15 days for 2-3 times continuously.

Treatment 2: spraying crown with 2%urea + 2%monopotassium phosphate +1500 times brassinolide for 10-15 days before winter (before and after fruit picking) to 12 months, spraying once for 10-15 days, and continuously spraying for 2-3 times, and mulching.

Treatment 3: spraying tree crowns with 2%urea + 2%monopotassium phosphate + 2000 times calcium magnesium boron +1500 times brassinolide for 10-12 months before winter (before and after fruit picking), spraying for 10-15d for 2-3 times continuously, covering with plastic film for 12 months, and removing dead branches and fallen leaves in the garden after fruit picking for 11 months, and burning or deeply burying the rotten fruits in a concentrated way. 10 parts of quicklime, 2 parts of lime-sulfur mixture, 1 part of salt and 10 parts of clear water to prepare a pasty whitewashing agent for brushing.

Treatment 4: and (5) removing dead branches and fallen leaves in the garden after 11 months of fruit picking, and intensively burning or deeply burying the rotten fruits. 10 parts of quicklime, 2 parts of lime-sulfur mixture, 1 part of salt and 10 parts of clear water are mixed into pasty liquid for whitening the trunk.

Treatment 5: spraying clean water.

The medicaments used are shown in Table II.

Watch II

2. Investigation method

The control effect is investigated for 20 days in 3 months when the disease of the round spot is basically stable. Every 3 fruit trees are repeatedly investigated, 5 points are investigated according to 5 directions in the north and south of the east, 1 tip is investigated for each point, 15 tips are all investigated for each tip, the number of harmful blade stages is recorded, and the blade harmful index and the blade protecting effect are calculated.

Leaf disease grading standard: grade 0, no disease; 1 grade, the area of the disease spots accounts for less than 5% of the whole leaf area; stage 3, the area of the lesion accounts for 6% -10% of the whole leaf area; stage 5, the area of the disease spots accounts for 11% -25% of the whole leaf area, and stage 7, the area of the disease spots accounts for 36% -50% of the whole leaf area; grade 9, the area of the disease spots accounts for more than 51% of the whole leaf area.

The drug effect calculation method comprises the following steps: disease index = Σ [ leaf number of each stage disease (fruit) x relative stage number ]/(total leaf number of investigation x 9] ×100)

Prevention effect (%) = [ control area disease index-treatment area disease index ] +% control area disease index×100

Statistical data were analyzed using the SPSS 20 software system and differential significance analysis was performed using the danken new complex polar error method (DMRT).

3. Test results

Investigation result table of winter nutrition leaf-protecting test (Table III)

The results show that the tree crown is sprayed with 2 permillage urea, 2 permillage monopotassium phosphate, 2000 times of calcium magnesium boron and 1500 times of brassinolide for 10-15d for one time, and is continuously sprayed for 2-3 times before winter, and the tree trunk is brushed white, so that the tree body resistance can be effectively enhanced, fallen leaves and morbidity can be reduced, and the control effect can reach 87.71%. The measures are particularly important for orchards with serious diseases, and can help to resist the outbreak of the upcoming round-spotted disease in the late 12 months and reduce the disease incidence degree.

S2, reasonably trimming and keeping the new shoots

According to the early observation, the leaf spot of the lemon is mainly generated in winter, and the leaves, fruits and branches of the whole tree can be damaged, and the leaves, fruits and branches which are not mature in winter and the leaf blade of the middle and lower part of the tree body are particularly serious. In order to reduce the occurrence of diseases, the tree crowns are kept to be ventilated and light-transmitting, key young shoots are kept, and summer shoots are treated in time. Aiming at the climate situation that the three gorges reservoir area is high in temperature and wet and fog is too much, the lemon adopts a natural open-heart tree shape, and is subjected to chopping, thinning, retraction, sawing of big branches, pruning of withered branches, pest branches, weak bore branches, random branches, overgrowth branches and the like until the budding of the next spring, and the like, so as to prevent the closing. The pruning in other seasons takes the flower quantity into full consideration, mainly takes light pruning as a main part, and in spring, according to the size of the tree and the tree vigor, the proportion of spring tips, flower buds and young fruits is adjusted by partially overlapping and crossing branches in a short section, so that the fruit retaining quantity is determined, and the purpose of strengthening the tree vigor is achieved; in summer, bud picking, tip placing and core picking are carried out on the young tree, flower buds and young fruits are removed in time, xia Shao is carried out on the adult fruit tree, and excessive flower branches are removed; and (3) erasing scattered early autumn tips and trunks in autumn, girdling, advancing the tip placing time to 8 months, placing the early autumn tips in order, picking the tips timely when the early autumn tips grow to 6-8 leaves, enhancing fertilizer and water management, and spraying 1-2 times of monopotassium phosphate to enable the early autumn tips to be lignified. And the late autumn tips sprouted in the middle ten days of 9 months are timely erased, the malformed fruits and the excessively dense fruits are dredged, and the cold resistance and the disease resistance are enhanced. Aiming at saplings, the cultivation of crowns is mainly carried out, and the saplings can be cut off to a long length and summer tops with little or no cutting, and the saplings can be cultivated early, so that enough good fruiting parent branches can be cultivated.

Meanwhile, aiming at the orchard with overlarge density in early stage orchard establishment, reasonable interval cutting, spacing plant or interlaced interval cutting is adopted, and ventilation and light transmission of the tree body are enhanced.

S3, reasonable load and timely harvesting

Lemon has the characteristics of flowering and fruiting in four seasons and long picking period. According to the previous investigation, the white sheep in the Wanzhou area blindly pursues the current annual output, the output is often more than 3000 kg/mu, the higher output is more than 3500 kg/mu, and the load capacity of the tree body is exceeded for a long time, so that serious defoliation, weakening of the tree body and serious reduction of resistance to various diseases are caused.

1. Reasonable load, adjust yield

In order to reduce the occurrence of diseases, proper planting density is maintained, and the tree crowns are ventilated and transparent, and flower in and out and layered three-dimensional results are obtained. The residual fruits, the undersize fruits and the top fruits of the lemon are removed before bagging so as to control the fruit remaining amount, and the fruit remaining amount is controlled to be about 2000 kg/mu, so that the tree vigor is recovered, the years are lightened, and the high yield and stable yield are ensured. The fruit retention part is the inner chamber of the tree body and the middle lower part.

2. Timely harvesting after the fruit is ripe

In the ten thousand state lemon producing area under the unique geographical climate condition of the three gorges reservoir area, flowers and fruits are bloomed four seasons for one year, and are harvested for 3 times, namely spring flowers and fruits, xia Huaguo and autumn flowers and fruits, mature fruits, immature fruits, young fruits and flowers exist in each season at the same time, the picking workload is large, and the fruits are often difficult to distinguish, so that the early and middle matured varieties such as lemon, vone navel orange, granulated sugar orange and the like are timely picked in each batch, the early and middle matured varieties are finished in the last middle ten days of 11 months, firstly, the tree burden is reduced for timely picking, secondly, the later low-temperature coming is avoided, the round spot bacteria show spots on the fruit surfaces, and the commodity of the fruits is reduced. And after harvesting, removing the unpicked residual fruits and winter flowers and fruits of the hanging tree in time, thereby avoiding providing favorable conditions for pathogen infection.

3. Enhanced post-harvest management

And (3) applying a positive fertilizer of 1.0-1.5 jin/plant in time after each fruit picking, and supplementing nutrients to the tree body so as to be beneficial to restoring the tree vigor and enhancing the disease resistance of the tree body. If the young shoots are sucked out in Qiu Xin, the young shoots are timely aged by being matched with spraying foliar fertilizer to supplement phosphorus, potassium, calcium, magnesium, boron and other medium trace elements, if the young shoots are sucked out in summer, the young shoots are timely wiped out, the young shoots can be picked up or cut off to promote the growth of regular autumn shoots, and good fruiting parent shoots are cultivated.

S4, comprehensively and thoroughly cleaning garden

1. And (5) centralized treatment of the diseased tissue. Orchards with lemon round spot, after fruit picking in winter and before sprouting, and before each new tip extraction, the secondary fruit, diseased leaf and diseased branch of the tree are cut off in time, and the dead branches, fallen leaves, rotten fruits and dead branches in the orchards are removed, and are buried deeply or burnt intensively.

2. And cleaning the garden with the medicament in winter. According to early observation, the disease of the round spot of the lemon is mainly generated in winter, the leaves, fruits and branches of the whole tree can be damaged, the branches, the leaves and the fruits which are not mature in winter, and the disease of the leaves at the middle and lower part of the tree body in spring and autumn are particularly serious, and the disease severity of the round spot of the current year can not be reduced by the agent cleaning in winter, but the disease base of bacteria in the next year is reduced, and the disease severity in the next year is reduced. Spraying 1500 times of 25% prochloraz in whole garden after fruit picking (11 months and ten days), spraying 1-degree Baume lime sulfur or 0.5-0.8% time of Baume liquid in whole garden after extremely low temperature in winter, thoroughly spraying crowns and floors, scraping off lesions, moss and cocktail on trunks and main branches, and mixing 10 parts of quicklime, 2 parts of lime sulfur, 1 part of salt and 10 parts of clear water into pasty liquid trunk for whitening. By doing so, the sterilization is facilitated, the warming and warming effects can be achieved, and the freezing injury is reduced.

3. The medicament is used for cleaning the garden in spring. The spring garden cleaning of the lemon round spot is important for reducing the occurrence severity of the round spot. The disease time of the lemon round spot is from the middle 12 months of the first year to the middle 3 months of the next year, and the disease is not further extended. In winter, germs in the first year infest tissues in the extraction period of various tips such as spring, summer, autumn and the like, and the damage is only outbreak when the temperature is reduced, and the spraying of more medicaments at the moment can not prevent the development of the germs in the current year. Therefore, the cleaning of the garden in spring is more critical than the cleaning of the garden in winter. In the middle ten days of 2 months before lemon sprouting, namely the disease degree caused by the first year of round spot bacteria is fixed, the extension is not continued, and when new shoots are not extracted in the year, 40% of tebuconazole, 800 times or 97% of mineral oil, 150-200 times of liquid or 40% of pyridaben, 5000 times or 22.4% of spirotetramat are sprayed for spring garden cleaning. Note that the alternate rotation and the compound medication improve the prevention and treatment effects of the medicament.

S5, precise chemical agent control

According to a large quantity of investigation of the occurrence condition of the early-stage orchard round-spotted disease, the disease features of the round-spotted disease of the lemon in the special climate of the three gorges reservoir area are mainly represented by the fact that the disease period is from 12 middle ten days to 3 middle ten days, the disease spots are basically not continuously spread after 3 middle ten days, and the severity is stable. The affected parts are mainly represented by spring tips, autumn tips, aged leaves, summer tips, un-aged late autumn tips and leaves at the middle and lower parts of the tree body. If fruits are not picked in winter, the fruits are infected with round spot disease, including mature fruits and partial immature young fruits. Therefore, the prevention and treatment of the lemon round spot disease takes prevention as a main principle and comprehensive prevention and treatment as a principle, and chemical prevention and treatment are timely and accurately carried out aiming at different tip drawing periods and result characteristics.

In the year 2019 to 2022, field efficacy tests are carried out in Huimin villages, double-stone communities and Bai Yancun of white sheep, 4 effective medicaments are screened, 4 combinations with better prevention effect are screened, the screened effective medicaments are recommended to farmers nearby a base at present, better prevention and control effects are shown compared with the traditional medicaments, the farmers can receive more than 500kg of yield per mu from the best, and better economic benefits are shown. The specific scheme is as follows:

1. pesticide application method

Different medicaments are selected, and the crown, the trunk and the ground are sprayed for 1 time in the spring tip extraction period and the pre-flowering period in the middle and the last ten days, the summer tip extraction period of 5 to 6 months, the autumn flowering period and the autumn tip extraction period of 7 to 8 months, and the crown, the trunk and the ground are sprayed for 5 to 6 times in total after fruit picking of 11 to 12 months and before low temperature comes.

2. Investigation method

Investigation was conducted when the onset was stable and no further expansion was continued. 3 trees per cell, 3 replicates per treatment. Sampling at 4 points of east, south, west and north, and randomly investigating at least 30 leaves of 1-2 branches at each point. Calculating disease index and preventing and treating effect.

Leaf disease grading standard: grade 0, no disease; 1 grade, the area of the disease spots accounts for less than 5% of the whole leaf area; stage 3, the area of the lesion accounts for 6% -10% of the whole leaf area; stage 5, the area of the disease spots accounts for 11% -25% of the whole leaf area, and stage 7, the area of the disease spots accounts for 36% -50% of the whole leaf area; grade 9, the area of the disease spots accounts for more than 51% of the whole leaf area.

Disease index = Σ [ leaf number of each stage disease (fruit) x relative stage number ]/(total leaf number of investigation x 9] ×100)

Prevention effect (%) = [ control area disease index-treatment area disease index ] +% control area disease index×100

Table four

Data of field control effect investigation of different medicament treatments on lemon round spot (Table five)

Leaf disease is stable after 3 months and 25 days, the disease symptoms of the round spots are obvious, and the expansion is stopped, so that the investigation is easy to conduct. From the investigation data, the medicament selected in the test has a certain prevention effect on the lemon round spot disease, wherein the treatment 16>4>14>11>1>5>6>8>3>17>2>9>10>12>13>7>15>18, the highest prevention effect of 25% of the prochloraz is 94.73%, the highest prevention effect of 40% of the prochloraz is achieved by the treatment of 40% of the prochloraz and 2% of the amino oligosaccharin plus 0.5% of urea, the prevention effect of 91.63% of the prochloraz and the second of 60% of the benzol propiconazole is 91.51%, the prevention effect of 5 medicament of 80% -89% is achieved, and the medicament further comprises 3% of the mesogen and 29% of the lime sulfur agent/99% of mineral oil treatment. Both the two medicaments are green prevention and control main pushing medicaments, are cost-saving and efficiency-increasing medicaments and are green environment-friendly medicaments, and can be widely popularized and used for production as long as the administration period is well mastered. 4 medicines with the control effect of 60% -70% comprise 2%.8 hundred million/gram of Jinggang, ceriporia and novel plant immunity protein regulator, and the pesticide composition is also a biological inoculant and a nutrition supplementing product with relatively good control effect. The result of the control effect again proves that the control effect of the lemon round spot is to be improved, and the control effect can be improved from the aspects of supplementing plant nutrition and increasing stress resistance. The control effect is below 60% of the medicines, namely, the medicines are common in production, the control effect of 13% of thiabendazole is 59.91%, but the control effects of 70% of thiophanate-methyl, 25% of pyraclostrobin and 33% of chunleisu are below 32%, and the control effect is poor.

The results show that the prevention effect is more than 90% in the spring tip extraction period and the pre-flowering period in the middle and the last ten days, the summer tip extraction period of 5 to 6 months, the autumn flowering period of 7 to 8 months and the autumn tip extraction period, and after 11 to 12 months of fruit picking and before low temperature comes in the orchard with serious disease, 25% of silazol, prochloraz or 40% of tebuconazole, prochloraz or 2% of amino-oligosaccharin plus 0.5% of urea or 60% of benzol, propiconazole, wherein the prevention effect of 25% of silazol, prochloraz is the highest and reaches 94.73%. The difenoconazole has high prevention effect up to more than 85% by adopting 30% difenoconazole or 45% prochloraz or 3% Zhongshengmycin and 40% pyraclostrobin. Alternating and compound medication are noted, medium trace elements are reasonably supplemented, and the control effect of the medicament is improved. Therefore, in the prevention and control of the lemon round spot, the optimal prevention and control period is selected, the medicament with good prevention and control effect is used alternately, and the medicament is matched with auxiliary agents such as mineral oil or vegetable oil and the like, and the medicament is used alternately and the nutrition is supplemented, so that the good prevention and control effect can be achieved.

The foregoing is merely exemplary of the present invention, and specific technical solutions and/or features that are well known in the art have not been described in detail herein. It should be noted that, for those skilled in the art, several variations and modifications can be made without departing from the technical solution of the present invention, and these should also be regarded as the protection scope of the present invention, which does not affect the effect of the implementation of the present invention and the practical applicability of the patent. The protection scope of the present application shall be subject to the content of the claims, and the description of the specific embodiments and the like in the specification can be used for explaining the content of the claims.

Claims (4)

1. The green prevention and control method for the lemon round spot is characterized by comprising the following steps of:

s1, reasonably fertilizing and cultivating the tree vigor: applying 2 jin of high nitrogen sprouting fertilizer per plant for 2-3 months, and additionally spraying leaf fertilizer and brassin for 1 time; applying 2 jin of fruit strengthening fertilizer per plant in the last ten days of 6 months, and spraying foliar fertilizer for 1 time; applying 1.0-1.5 jin of still positive fertilizer after each batch of fruit picking after 8 months; applying 5 jin/plant of organic fertilizer for 9-10 months, and spraying foliar fertilizer for 1 time; 1 time of fruit picking fertilizer 1.5 jin/plant is added after pruning for 11-12 months, and brassin and foliar fertilizer are sprayed for 1-2 times; 10 months to 12 months, spraying Shi Shuguan with 2 permillage urea, 2 permillage potassium dihydrogen phosphate, 2000 times calcium magnesium boron and 1500 times brassinolide for one time, spraying for 10-15 days, and continuously spraying for 2-3 times, and mulching;

s2, reasonably trimming, and guaranteeing new tips: adopting a natural open heart tree shape, and cutting, thinning, retracting and sawing big branches of a fruiting tree from the time of fruit picking in winter to the time of sprouting in spring in the next year; the proportion of spring tips to flower buds and young fruits is regulated by partially overlapping and crossing branches through short cuts in spring; in summer, bud picking, tip placing and core picking are carried out on the young tree, flower buds and young fruits are removed in time, xia Shao is carried out on the adult fruit tree, and excessive flower branches are removed; erasing scattered early autumn tips in autumn and carrying out trunk girdling, putting the early autumn tips in 8 months in the middle and late days, picking the core when the early autumn tips grow to 6-8 leaves, and erasing late autumn tips sprouting after 9 months in the middle;

s3, reasonable load and timely harvesting: removing residual fruits, undersize fruits and top fruits before bagging, controlling the fruit retention amount to be about 2000 kg/mu, wherein the fruit retention parts are the inner chamber and the middle lower part of the tree body; harvesting each batch of fruits in time, and finishing harvesting in the middle ten days of 11 months;

s4, comprehensively and thoroughly cleaning a garden: spraying 25% prochloraz 1500 times liquid in whole garden in the middle and upper 11 months after fruit picking, and spraying one-time Baume 1 degree lime sulfur or 0.5% -0.8% Baume liquid in whole garden after extreme low temperature in winter to realize winter garden cleaning; spraying 800 times of 40% tebuconazole prochloraz or 150-200 times of 97% mineral oil or 5000 times of 40% pyridaben etoxazole or 5000 times of 22.4% spirotetramat to clear the garden in spring in the middle ten days of 2 months, and taking care of alternate rotation and compound medication;

s5, precise chemical prevention and treatment: 25% of silazole, prochloraz or 40% of penconazole, prochloraz or 2% of amino oligosaccharin plus 0.5% of urea or 60% of benzol, propiconazole or 30% of difenoconazole or 45% of prochloraz or 3% of zhongshengmycin or 40% of pyraclostrobin, and difenoconazole are sprayed on tree crowns, tree trunks and the ground for 1 time respectively; for the orchard with serious disease, after 11-12 months fruit picking and before low temperature comes, the preparation is sprayed for 1 time before the orchard is cleaned in winter.

2. The green prevention and control method for lemon round spot according to claim 1, which is characterized in that: applying fruit strengthening fertilizer 3-5 days before spraying fruit protecting agent and pesticide, spraying fruit protecting agent and pesticide when the diameter of fruit is about 40mm, and bagging after the sprayed liquid medicine and dew are dried.

3. The green prevention and control method for lemon round spot according to claim 1, which is characterized in that: the step S4 further includes: scraping off the lesions, moss and cocked skin on the trunk and the main branch, and then mixing 10 parts of quicklime, 2 parts of lime-sulfur mixture, 1 part of salt and 10 parts of clear water to obtain pasty liquid for whitening the trunk.

4. The method for controlling and controlling the lemon round spot according to claim 1, wherein the step S4 further comprises: after fruit picking in winter and before germination, and before each new shoot extraction, the secondary fruit, the diseased leaf and the diseased branch of the tree are cut off in time, and the dead branch, the fallen leaf, the rotten fruit and the dead branch in the garden are removed, and are buried deeply or burnt intensively.

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