CN110521511B - Pitaya brown rot comprehensive prevention and control method based on precise pesticide application and application thereof - Google Patents

Abstract

The invention discloses a comprehensive prevention and control method for pitaya brown rot based on precise pesticide application and application thereof. According to the method, based on continuous research on the catastrophe rule of the dragon fruit brown rot disease and screening of a sterilization agent with long lasting period and good systemic property, according to the characteristic that pathogenic bacteria are mainly harmful to young and tender tips, a prevention and control point is placed on the protection tender tips to be accurately applied, the disease prevention and control period is moved forward, the initial infection source is reduced, diseased fruit bearing branches are gradually replaced, the fruit damage rate is reduced, and the purpose of effectively controlling the orchard with serious dragon fruit brown rot disease is achieved. Through years of field tests and demonstration, the method can effectively control the occurrence and damage of the brown rot of the dragon fruits in the field, and greatly reduce the pesticide application times and the labor and drug cost.

Description

Pitaya brown rot comprehensive prevention and control method based on precise pesticide application and application thereof

Technical Field

The invention belongs to the technical field of plant protection, and particularly relates to a comprehensive prevention and control method for pitaya brown rot based on precise pesticide application and application thereof.

Background

Pitaya (Hylocereus undatus) is a perennial fleshy plant of Cactaceae family, genus Petasites, and is native to Central America, such as Brazil, Mexico, and the like. In the early 90 s of the 20 th century, Taiwan in China introduced into mainland after successful introduction of a test species. At present, the dragon fruits are planted in large areas in places such as Guangxi, Guangdong, Hainan, Fujian, Guizhou, Yunnan and the like in China, and the dragon fruits become one of important economic crops for farmers to lose poverty and become rich.

The brown rot, also called canker, of dragon fruit caused by the infection of new phaeosporium dimyridum is a devastating fungal disease that seriously threatens the development of the dragon fruit industry. The disease causes the fruit peel to be pitted so as to reduce the commodity value, and causes the stalks and the fruits to be rotten and dead so as to cause the average yield loss to be generally 20 to 30 percent and to be more than 50 percent when the disease is serious, even the garden is damaged. The perennial climate characteristics of high temperature and high humidity in the south China are very favorable for the outbreak and the prevalence of the dragon fruit brown rot.

At present, the prevention and treatment of the pitaya brown rot mainly depends on chemical pesticides, however, the selection of the pesticide with good prevention effect is not many, fruit growers often use a plurality of bactericides in a mixed mode, the chemical pesticides are sprayed almost once every week at the peak of disease occurrence, a large amount of financial and material waste and environmental pollution are caused, and the long-term use of the chemical pesticides is easy to cause the risk of drug-resistant wind. In addition, 4-6 batches of dragon fruits can be hung in one year, the fruits which just bloom in the same orchard are ripe, the chemical application time is not easy to select, the pesticide residue of the fruits is easy to exceed the standard, and the quality safety is affected. The whole growing season of the pitaya can be affected by brown rot, the most serious disease in south China is 5-9 months per year, the season is often high-temperature rainy, the field prevention and control effect which depends on chemical pesticides alone is poor, and a precise, efficient and safe comprehensive prevention and control method for the brown rot of the pitaya is urgently needed in production.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, advocates reasonable use of chemical pesticides according to the plant protection policy of prevention-oriented and comprehensive control, adheres to the control principle of agricultural and physical control-oriented and chemical control-oriented, and provides a comprehensive prevention and control method for the brown rot of pitaya based on precise pesticide application. Based on continuous research on the catastrophe rule of the pitaya brown rot and screening of a sterilization agent with long lasting period and good systemic property, according to the characteristic that pathogenic bacteria are mainly harmful to young and tender tips, the prevention and control stress point is placed on accurate pesticide application for protecting the tender tips, the disease prevention and control period is moved forward, the initial infection source is reduced, diseased fruit bearing branches are gradually replaced, the disease branch and fruit damage rate is reduced, and the aim of effectively controlling an orchard with serious pitaya brown rot is fulfilled. The method can effectively control the occurrence and damage of the brown rot of the dragon fruits in the field through field tests and demonstration for many years, and greatly reduces the pesticide application times and the labor and drug cost.

The invention also aims to provide application of the comprehensive prevention and control method for the pitaya brown rot based on precise pesticide application in pitaya cultivation.

The purpose of the invention is realized by the following technical scheme:

a comprehensive prevention and control method for pitaya brown rot based on precise pesticide application comprises the following steps:

(1) cleaning the garden after fruit picking in winter, cutting out diseased residual branches, scraping diseased residual spots, taking the diseased residual branches and the diseased residual spots out of the orchard, and spraying a bactericide in the whole garden; after clearing the garden, applying sufficient fertilizer;

(2) after the young shoots of the first batch of young shoots grow out in the beginning of spring, accurately applying the pesticide for multiple times until the young shoots are aged to serve as fruit bearing branches; during the sprout germination period, field management is enhanced;

(3) if the orchard is old, removing all grown non-bearing branch young shoots after the first young shoots are aged; if the orchard is newly built, the orchard is enabled to sprout new shoots again through conventional management, the new shoots are accurately applied with the pesticide again and protected until the new shoots are converted into mature shoots, the young shoots are used as fruit bearing branches, the number of the reserved young shoots is determined according to the tree vigor and the management level, and then all the young shoots of the non-fruit bearing branches growing subsequently are removed; after each batch of pitaya is successfully pollinated, if disease spots appear on the pitaya fruits at a proper disease period, a bactericide is sprayed in time for preventing and treating the disease spots;

(4) during the fruiting period of each batch of dragon fruits, field management is enhanced, a ventilated and light-transmitting growing environment is created, fruit bearing branches of old and weak diseases are gradually eliminated, and strong tree vigor is cultivated until fruit picking is finished all the year round.

The bactericide in the step (1) is preferably tebuconazole, iprodione, flusilazole, prothioconazole or fludioxonil, and is prepared for use in clear water; if the bactericide is sprayed for multiple times, the medicaments are alternately used, and only one medicament is applied each time.

The concentration of the active ingredients of the bactericide in the step (1) is preferably 500-1000 mg/kg. The high-concentration pesticide is applied to orchards with serious diseases, and the low-concentration pesticide is applied to orchards with light diseases.

The spraying frequency of the bactericide in the step (1) is preferably 1-2, and the whole plant is sprayed completely, thoroughly and uniformly; more preferably, the fertilizer is sprayed 1 time immediately after the diseased branches and the diseased spots are brought out of the orchard, and is sprayed 1 time again in 1 month the next year.

The fertilizer in the step (1) comprises an organic fertilizer and a compound fertilizer. And (4) fertilizing by adopting a conventional fertilizing mode and method.

The organic fertilizer is preferably at least one of high-quality organic fertilizer, decomposed chicken manure and peanut bran fertilizer with registration certificate.

The amount of the organic fertilizer is preferably 2-5 kg.

The compound fertilizer is preferably Norwegian ternary compound fertilizer (N-P-K: 15-15-15).

The amount of the compound fertilizer is preferably 0.1-0.25 kg of the plant application amount.

Accurately applying the pesticide for many times in the step (2), and spraying the pesticide on the whole plant when the tender tips do not exceed 5cm long; individual new branches can be cut off earlier so that the new branches grow uniformly and are convenient to manage.

The step (2) of accurately applying the medicine for multiple times comprises the following steps: the medicament is preferably tebuconazole, iprodione, flusilazole, prothioconazole, fludioxonil or propiconazole and is prepared in clear water; the preparation can be applied alternately by one preparation at a time.

The propiconazole has an inhibiting effect on the growth of young shoots and needs to be used after the young shoots are aged.

The step (2) of accurately applying the medicine for multiple times comprises the following steps: the concentration of the effective component of the medicament is preferably 500-1000 mg/kg.

The step (2) of accurately applying the medicine for multiple times comprises the following steps: the application time is preferably one time per interval of 15-25 d. The orchard with serious morbidity takes high-concentration pesticide application, and the pesticide application interval time is short; the orchard is applied with low-concentration pesticide with light morbidity, and the pesticide application interval is long.

The old orchard in the step (3) is an orchard which has fruit bearing for more than 2 years and has disease index rate or disease fruit rate of more than 40%, and the newly-built orchard is an orchard which has no fruit bearing or little fruit bearing within 2 years.

The bactericide in the step (3) is preferably tebuconazole, iprodione, flusilazole, prothioconazole or fludioxonil, and is prepared for use in clear water; if the bactericide is sprayed for multiple times, the medicaments are alternately used, and only one medicament is applied each time.

The spraying time of the bactericide in the step (3) is preferably from the initial flowering stage to the initial fruiting stage of each batch of pitaya.

The spraying frequency of the bactericide in the step (3) is preferably 1-2, and the whole plant needs to be sprayed completely, thoroughly and uniformly.

The concentration of the active ingredients of the bactericide in the step (3) is preferably 100-250 mg/kg. The high-concentration pesticide is applied to the orchard with serious morbidity for 2 times; the low-concentration pesticide is applied to the orchard with light morbidity for 1 time.

And (4) determining the number of the retained young shoots according to the tree vigor and the management level in the step (3), and preferably retaining 6-10 young shoots per plant.

The step (4) of gradually eliminating fruit bearing branches of old and weak diseases is realized through a conventional orchard management mode, and specifically comprises the following steps: 1) arranging 6-10 bearing branches of each plant in the fruiting period of the dragon fruit, erasing buds and flowers of other branches, reducing the growth angle of the branches, promoting vegetative growth, and culturing into strong prepared bearing branches; 2) in the flowering and fruiting period, cutting off redundant nutrient branches to reduce nutrient consumption and increase sunlight irradiation; in order to ensure the fruit quality, artificial flower thinning is carried out 7-8 days after buds appear, and 3-4 full buds are reserved on each bearing branch of each batch of flowers; after flowers withering for 5-7 days, selecting and reserving 2-3 healthy fruits which are successfully pollinated for each branch, and uniformly pruning the other fruits; the preserved fruits can be bagged by kraft paper, so that the uniform maturity and the consistent commodity of the fruits can be ensured, the biting of insects and bees can be avoided, and the requirements of pollution-free edible safety standards can be met; 3) after fruit picking, weak branches and strong branches are removed, old branches with 2-3 years old and more fruits, insect-disease branches and bottom-layer weak branches are removed, and nutrition accumulation of mother branches in the next round of fruit picking is facilitated.

The enhanced field management in the method provided by the invention is all conventional management measures for an orchard, and comprises management of water fertilizer, weeding, insect pests and the like, and specifically comprises the following steps: 1) water content management: in the fruit expansion period, the soil is kept moist to facilitate the growth of fruits; 2) fertilization management: the fruit bearing trees mainly use organic fertilizers and auxiliary fertilizers, the fertilizers are low-nitrogen, high-phosphorus and high-potassium ternary compound fertilizers, the fertilizers are mostly applied in a broadcasting mode, ditching and deep application are avoided, roots are prevented from being damaged, 1-2 kg of organic fertilizers and 0.1-0.25 kg of ternary compound fertilizers are applied to plants in a fruit expanding period, and leaf fertilizers are sprayed outside the roots for 1-2 times after each batch of young fruits are formed, so that the fruit quality is improved; 3) weeding management: weeding by a machine preferentially, and covering the periphery of the base of the stem of the dragon fruit with cut grass; 4) insect pest management: the prevention and control of the fruit which is harmed by the eating flies are carried out by the measures of fruit bagging, yellow plate hanging, insecticide spraying and the like.

The application of the comprehensive prevention and control method for the pitaya brown rot based on accurate pesticide application in the pitaya cultivation is provided.

Compared with the prior art, the invention has the following advantages and effects:

the inventor selects a sterilization agent with long lasting period and good systemic property based on continuous research on the catastrophe rule of the dragon fruit brown rot, puts a prevention and control point on accurate pesticide application for protecting young tips according to the characteristic that pathogenic bacteria are mainly harmful to young and tender tips, reduces an initial infection source by advancing a disease prevention and control period, gradually replaces diseased fruit bearing branches, reduces the harmful rate of diseased branches and fruits, and achieves the purpose of effectively controlling orchards with serious dragon fruit brown rot.

(1) On the prevention and control way, the disease prevention and control move forward, so that tender tips are mainly protected, and the initial infection source is reduced. The method fully utilizes the catastrophe rule of the dragon fruit brown rot and a bactericidal agent with long lasting period and good systemic property, grasps the characteristic that germs are difficult to infect mature branches, puts the emphasis on disease prevention and control on the protection of young tips in spring, utilizes sufficient winter fertilizer application to promote young tips to germinate and strengthen young tips in early spring, protects young tips to be mature through the precise pesticide application mode of pesticide application and pesticide application, then cuts off the young tips of non-bearing branches grown subsequently, gradually eliminates the weak bearing branches, and can greatly reduce the dragon fruit brown rot.

(2) In the prevention and control strategy, attention is paid to strengthening water and fertilizer management, and the disease resistance of the dragon fruits is fully exerted. Strong branches are cultivated, young tips are aged more quickly, the health of the branches is guaranteed, the probability of fruit infection is reduced as much as possible, and the subsequent cost of disease control is greatly reduced. In addition, the orchard with serious disease needs to pay special attention to the prevention and control of ants, and the ants crawl around, so that pathogenic bacteria are easily infected to young shoots or fruits.

(3) In the aspect of preventing and controlling medicament selection, medicaments with strong systemic property, long lasting period and wide bactericidal spectrum are fully utilized to achieve the purposes of one-time application and other fungal diseases prevention. In the tebuconazole, iprodione, flusilazole, propiconazole, prothioconazole, fludioxonil and other medicaments selected in the invention, except fludioxonil, other medicaments have the characteristics of strong systemic property, long lasting period, wide bactericidal spectrum and the like, and are subjected to indoor determination and field prevention and control practice of the inventor, one medicament is selected for each application (wherein the propiconazole medicament is used in the middle and later growth period of young shoots), a liquid formulation product of a large foreign pesticide company is preferably selected, other application auxiliaries are not required to be added, the good prevention and control effect is achieved, the pertinence and the effectiveness of disease prevention and control are greatly improved, and the prevention and control cost of fruit growers is remarkably reduced.

(4) In the selection of the application concentration, the matching of the high and the low is noticed. When no fruit is available in the young shoot stage of the pitaya in spring or in an orchard with serious disease, the pesticide application concentration of the bactericide can be properly increased, the pesticide application frequency and concentration of the bactericide are reduced after fruit hanging, even the bactericide is not applied, the risk of exceeding the standard of pesticide residue of the fruit is greatly reduced, and the product quality safety is improved.

(5) On the aspects of operability and prevention and control effect of the prevention and control method, the comprehensive prevention and control method based on accurate pesticide application is tightly combined with the conventional management method, the pesticide application and the pesticide application are mainly repeated to protect young shoots, the young shoots of non-fruiting branches are cut off, the initial infection source is reduced, the operability is high, and the prevention and control cost of farmers is greatly reduced. For orchards with serious diseases, the disease of the current year can be effectively controlled by implementing the comprehensive prevention and control method for the pitaya brown rot, and the method can play a good role in preventing the orchards without diseases.

Drawings

Fig. 1 is a diagram of indoor bacteriostatic effect of the efficient prevention and treatment medicament for the dragon fruit brown rot, wherein a diagram (A) is the bacteriostatic effect of a tebuconazole suspending agent of 430 g/l, and a diagram (B) is the bacteriostatic effect of 50% fludioxonil wettable powder.

Fig. 2 is a graph showing the growth of dragon fruits in the old orchard in example 2, wherein the graph (a) shows the growth of dragon fruits without drug application control in the control area, and the graph (B) shows the growth of dragon fruits with drug application control in the test area.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

EXAMPLE 1 selection of the type of germicide

Selecting 16 bactericides with better antibacterial effect reported in literature or commonly used in production, adding different medicaments with the same concentration (1000mg/kg) and the same volume into a PDA flat plate hole mixed with a conidium of a pathogen (the pathogen is the new cylindrosporium dimyridum) DF-CH8 which is disclosed on GenBank and has the accession number of JX128103.1) by adopting an antibacterial ring method, culturing at 25 ℃, and measuring the duration of the different medicaments for inhibiting the growth of the hyphae of the pitaya brown rot pathogen under the in vitro condition by observing the disappearance time of the antibacterial ring, wherein the results are shown in Table 1.

The result shows that 5 medicaments such as 50 percent fludioxonil wettable powder, 250 g/L propiconazole emulsifiable solution, 40 percent propiconazole suspending agent, 430 g/L tebuconazole suspending agent, 400 g/L flusilazole emulsifiable solution and the like have large and obvious inhibition zones on the brown rot of the pitaya through observing the disappearance time of the inhibition zones, the inhibition zones do not disappear after the culture for 15 days in opposition, and the long inhibition duration is shown. Wherein, the bacteriostatic effect of the tebuconazole suspending agent of 430 g/L is shown in figure 1(A), and the bacteriostatic effect of the fludioxonil wettable powder of 50 percent is shown in figure 1 (B). The 500 g/L iprodione suspending agent has a large and obvious inhibition zone on the dragon fruit brown rot, the inhibition zone becomes small after the confronting culture is carried out for 13 days, the inhibition zone does not completely disappear after the confronting culture is carried out for 15 days, and a longer inhibition duration period is also shown. The prochloraz aqueous emulsion of 450 g/L, difenoconazole emulsifiable concentrate of 250 g/L, wettable powder of myclobutanil of 40% and other 3 medicaments have obvious inhibition zones on the brown rot of dragon fruit in early stage, and the inhibition zones disappear gradually after the confronting culture is carried out for 9-11 days, thus showing moderate inhibition duration. The early-stage inhibition zones of 3 medicaments, such as 50% carbendazim wettable powder, 40% thiabendazole wettable powder, 250 g/l azoxystrobin suspending agent and the like, on the brown rot of the pitaya are obvious, the inhibition zones gradually disappear after the confronting culture is carried out for 5-7 days, and the inhibition duration is general. 4 medicaments such as 70% propineb wettable powder, 2% kasugamycin aqueous solution, 75% chlorothalonil wettable powder, 125 g/l epoxiconazole suspending agent and the like have small inhibition zones on the brown rot of the pitaya in the early period, and the inhibition zones basically disappear after the culture for 3 days in opposition, thus showing short inhibition duration. Therefore, in the chemical control practice of the dragon fruit brown rot, the fungicide varieties with long lasting period, such as tebuconazole, propiconazole, prothioconazole, fludioxonil, iprodione, flusilazole, and the like, are preferably selected.

The radius of the inhibition zone of table 116 bactericides on the brown rot pathogen of dragon fruit and the duration of in vitro inhibition

Note: "-" indicates no zone of inhibition or disappearance of zone of inhibition

Example 2 Integrated prevention and control of Pitaya brown rot in old orchards

A20-mu orchard (variety type is red-pulp dragon fruit) in Shang-an town of Zijin county in Heyuan City of Guangdong province is built in 2012 spring, and is cultivated by cement columns, wherein 4 dragon fruits per column are cultivated by 110 cement columns per mu. Because the grower lacks the plant protection knowledge and does not know the disease control method, the brown rot of the dragon fruit is serious every year, the phenomenon of the flower skin of the fruit is prominent, the diseased tip and the diseased fruit rate almost reach 100 percent, the yield is low, and the economic benefit is poor. The inventor uses the orchard as a test demonstration point in the last 12 th month of 2016, and conducts demonstration by using the comprehensive prevention and control method for the pitaya brown rot based on accurate pesticide application. The specific operation is as follows:

(1) clearing the garden in winter and reducing the initial infection source; applying enough winter fertilizer and cultivating the strong tips in the next year.

And (3) pruning branches with serious diseases in the middle ten days of 12 months, digging out large disease spots on the aged branches, particularly, digging out the disease spots with small black spots, taking the disease spots out of the garden and burning or deeply burying and destroying the disease spots. After the garden is cleared, 500 g/L of iprodione suspension agent 500 times liquid is sprayed immediately, the pesticide is sprayed completely and uniformly, and clear water is prepared immediately before use, so that the aim of thoroughly clearing the garden is fulfilled. And spraying 1000 times of liquid of 50% fludioxonil wettable powder once again in the first ten days of 1 month in the next year. Uniformly and annularly spreading 20 jin of high-quality organic fertilizer, 1 jin of fine peanut bran powder and 0.5 jin of Norway compound fertilizer around the cement column by about 30cm, and paying attention to the fact that the fertilizer cannot contact the base of the dragon fruit stem. The middle of the two rows of cement columns is provided with a deep drainage groove, and the applied winter fertilizer is covered by soil, so that a foundation is laid for cultivating strong trees in the next year. In addition, the film is covered to prevent frost in winter frost weather.

(2) The young shoots are protected to be aged by accurate pesticide application, robust young shoots are cultivated, and the young shoots are aged.

In the first 3 th month, 430 g/L of tebuconazole 500 times liquid suspension agent is sprayed once, in the first 4 th month, 400 g/L of flusilazole 500 times liquid suspension agent is sprayed once, in the second 4 th month, 430 g/L of tebuconazole 500 times liquid suspension agent is sprayed once, and in the middle 5 th month, 250 g/L of propiconazole 500 times liquid suspension agent is sprayed once. All the medicaments are required to be sprayed completely, thoroughly and uniformly, and clear water is prepared for use. The water and fertilizer management is carried out according to a conventional method, and the specific operation is as follows: the mower mows, mows the grass to cover the periphery of the cement column, pays attention to the fact that the soil is kept moist, and norwegian compound fertilizer is applied every 20-30 days, and 0.5 jin is applied to each cement column every time. The pest control is carried out according to conventional management, and the high-efficiency cypermethrin is sprayed for controlling ant and moth larvae for one time in 3 middle and 4 middle months.

(3) And removing the young tips of the non-fruiting branches grown after the first young tips are aged, and preventing fruit infection.

And in the last 5 months, the first batch of young shoots are converted into old shoots, individual old young shoots with diseases are cut off, healthy bearing branches are remained, all grown young shoots of non-bearing branches are cut off after the first batch of young shoots are aged, and the young shoots are intensively burnt or deeply buried away from a orchard. In late ten days of 5 months, the first batch of flowers blooms, and 1000 times of solution of 20% prothioconazole suspending agent is sprayed once after the first batch of fruits successfully bear fruits; in late 7 th month, spraying 2000 times of a tebuconazole suspending agent solution of 430 g/L once after the second batch of fruits are successfully fruited; in late 8 th month, after the third batch of fruits is successfully fruited, applying 2000 times of solution of flusilazole missible oil of 400 g/L once; in the last 10 months, 2000 times of the iprodione suspending agent is sprayed once after the fourth batch of fruits (the last batch of fruits) are successfully fruited, wherein the amount of the iprodione suspending agent is 500 g/L. All the medicaments are required to be sprayed completely, thoroughly and uniformly, and clear water is prepared for use.

(4) And in the fruit bearing period, water and fertilizer management is enhanced, and fruit bearing branches of old and weak diseases are gradually eliminated.

The fruit expansion period is to keep the soil moist to facilitate the growth of the fruits. 10kg of decomposed chicken manure and 0.4kg of ternary compound fertilizer are uniformly spread on each cement column every time a batch of fruits are hung. 30-40 bearing branches are arranged on each cement column every time, and buds and flowers are removed from other branches to serve as prepared bearing branches. And manually thinning the flowers 7d after the buds emerge, and reserving 3-4 full buds on each bearing branch of each batch of flowers. And (5 d) after flowers are withered, selecting and reserving 2-3 healthy fruits which are successfully pollinated for each branch, and uniformly pruning the other fruits. The fruit is bagged by a special bagging net, so that the fruit flies are prevented from being damaged. After each fruit picking, thinning and keeping strong, shearing old branches, insect-infected branches and bottom-layer weak branches which have more fruits and are grown for 2-3 years, and gradually eliminating fruit-bearing branches with old and weak diseases.

(5) And (5) timely clearing the garden after the fruit picking is finished all the year round, applying sufficient winter fertilizer, and cultivating the strong tips of the next year.

And after the last batch of fruits is harvested, immediately starting to clear the garden, and performing garden clearing and fertilization in winter according to the method for clearing the garden and fertilizing in winter.

In the test, 1 row (10 cement columns) was left as a control zone without applying the bactericide, and the control zone was operated exactly the same except that the bactericide was not applied. The growth status of dragon fruit in the control area is shown in FIG. 2 (A).

The method is strictly carried out according to the method, the prevention and control of the dragon fruit brown rot in the fruit field have a good control effect, the diseased tip and the diseased fruit rate in the current year are greatly reduced, the diseased spot area of the disease accounts for less than 10% of the whole young tip or the whole fruit peel area, the disease is sporadically developed, and the investigation result is shown in table 2. After the comprehensive prevention and control method is used for two consecutive years, the diseased tip rate and the diseased fruit rate of the dragon fruit in the second year of the fruit field are further reduced, and the investigation result is shown in table 3. The growth conditions of the dragon fruits in the test area are shown in FIG. 2 (B). The dragon fruit brown rot of the fruit field is effectively controlled finally, and the economic benefit is obviously improved.

TABLE 2 Pitch and fruit incidence survey in dragon orchards in which the method of the invention was carried out in the first year

Note: sampling at random 5 points, investigating 20 young shoots or 20 fruits at each point, and grading according to the proportion of diseased shoots or diseased fruits. Level 0: the whole young sprout is free from disease spots or the epidermis of the fruit is free from disease spots; level 1: the lesion area accounts for less than 5% of the whole young sprout or the whole peel area; and 3, level: the lesion area accounts for 6 to 10 percent of the whole young sprout or the whole fruit peel area; and 5, stage: the lesion area accounts for 11 to 20 percent of the whole young sprout or the whole fruit peel area; and 7, stage: the lesion area accounts for 21 to 40 percent of the whole young sprout or the whole peel area; and 9, stage: the lesion area accounts for more than 41% of the whole young sprout or the whole peel area.

TABLE 3 Pitch and fruit incidence survey in Dragon orchards in which the method of the invention was carried out in the second year

Note: the investigation method is the same as in Table 2.

Example 3 comprehensive prevention and control of brown rot in newly-built dragon orchard

A50-mu orchard (the variety is red-pulp dragon fruit) is built in a subordinate district of Guangzhou city of Guangdong province at the end of 2017, transplanting is carried out at the end of 2 months in 2018, row-type cultivation is carried out, drip irrigation and spray irrigation facilities are arranged, grass is prevented by covering with a breathable plastic film, and 1000 plants are planted per mu. The grower has certain planting management experience, the management level is higher, but the grower lacks the plant protection professional knowledge, and the problems of abuse and indiscriminate use exist because a large amount of bactericide is mixed for each pesticide application. The inventor takes the orchard as a test demonstration point in the last 4 months of 2018, and the dragon fruit brown rot in the orchard happens sporadically, so that the development and spread of diseases are effectively controlled by the comprehensive prevention and control method for the dragon fruit brown rot. The specific operation is as follows:

(1) and (4) fertilizing to attack the young shoots, and protecting the new shoots until all fruits are hung and young shoots are aged.

And the water and fertilizer management is carried out according to a conventional method, the branches are trimmed according to the conventional method, and the cut branches are taken out of the garden and are intensively burnt or deeply buried. Spraying 430 g/L of tebuconazole 500 times liquid in the first ten months of 4 months, spraying 400 g/L of flusilazole emulsifiable solution 1000 times liquid in the middle ten months of 5 months, spraying 1000 g/L of iprodione suspending agent 1000 times liquid in the last ten months of 6 months, spraying 250 g/L of propiconazole emulsifiable solution 1000 times liquid in the last ten months of 7 months, spraying 3000 times liquid of 50% fludioxonil wettable powder in the last ten months of 8 months, and spraying 430 g/L of tebuconazole 1000 times liquid in the last ten months of 9 months. The bactericide is not sprayed for 10-12 months. The spraying is complete, thorough and even in each application, and the clear water is prepared for use. And during 6-9 months, spraying water mist at noon when the sun is sunned so as to reduce the field temperature and avoid the dragon fruit stalks from being burnt by the sun. The pest control is carried out according to conventional management, and the high-efficiency cypermethrin is sprayed for controlling ant and moth larvae once in the middle ten days of 4 months and 5 months.

(2) The pesticide application concentration and times are determined according to the number of brown rot spots of the dragon fruit branches in the orchard during fruit bearing.

In late 9 th month, the first batch blossoms, and after the first batch of fruits are successfully pollinated, the dragon fruits have few brown rot branches, so that no bactericide is applied. And performing water and fertilizer management, shaping and pruning, flower and fruit management and the like in the fruit bearing period according to a conventional method. The fruit is bagged by a special bagging net, so that the fruit flies are prevented from being damaged.

(3) Cleaning garden in time after picking fruit, and applying enough winter fertilizer.

And (5) cleaning the garden in time after the first fruiting and harvesting in the 12-month new garden is finished. The diseased branches are cut, large disease spots on the aged branches are dug out, particularly, disease spots with black small spots are dug out completely, and the diseased spots are brought out of the garden and are burnt or buried deeply. After the garden is cleared, a 500-time solution of 250 g/L propiconazole missible oil is sprayed once in the whole garden. 2 tons of high-quality organic fertilizer, 200 jin of peanut bran fine powder and 50 jin of Norway compound fertilizer are broadcast and applied per mu. The fertilizer does not contact the base of the dragon fruit stem, and the soil is used for covering the applied winter fertilizer, so that a foundation is laid for cultivating strong trees in the next year.

By adopting the comprehensive prevention and control method, the brown rot of the new dragon fruit garden is extremely slight, the scab of branches occurs sporadically, the incidence of fruit diseases is within 5 percent, and the occurrence and spread of the brown rot of the dragon fruit are effectively controlled.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.

Claims (5)

1. A comprehensive prevention and control method for pitaya brown rot based on accurate pesticide application is characterized by comprising the following steps: the method comprises the following steps:

(1) cleaning the garden after fruit picking in winter, cutting out diseased residual branches, scraping diseased residual spots, taking the diseased residual branches and the diseased residual spots out of the orchard, and spraying a bactericide in the whole garden; after clearing the garden, applying sufficient fertilizer;

(2) after the young shoots of the first batch of young shoots grow out in the beginning of spring, accurately applying the pesticide for multiple times until the young shoots are aged to serve as fruit bearing branches; during the sprout germination period, field management is enhanced;

(3) if the orchard is old, removing all grown non-bearing branch young shoots after the first young shoots are aged; if the orchard is newly built, the orchard is enabled to sprout new shoots again through conventional management, the new shoots are accurately applied with the pesticide again and protected until the new shoots are converted into mature shoots, the young shoots are used as fruit bearing branches, the number of the remained young shoots is determined according to the tree vigor and the management level, and then all the young shoots of the non-fruit bearing branches growing subsequently are removed; after each batch of pitaya is successfully pollinated, if disease spots appear on the pitaya fruits at a proper disease period, timely spraying 1-2 times of sterilization agent for preventing and treating;

(4) during the fruiting period of each batch of dragon fruits, field management is enhanced, a ventilated and light-transmitting growing environment is created, fruit bearing branches of old and weak diseases are gradually eliminated, and strong tree vigor is cultivated until fruit picking all year round is finished;

the bactericide in the step (1) and the step (3) is tebuconazole, iprodione, flusilazole, prothioconazole or fludioxonil, and is prepared in clear water; if the bactericide is sprayed for multiple times, the medicaments are alternately used, and one medicament is applied each time;

the concentration of the effective components of the bactericide in the step (1) is 500-1000 mg/kg;

spraying the bactericide in the step (1) for 1-2 times;

the accurate pesticide application in the step (2) is to spray the pesticide on the whole plant when the tender tips do not exceed 5cm long; individual new branches are cut earlier so that the new branches grow uniformly and are convenient to manage;

the medicament in the accurate application in the step (2) is tebuconazole, iprodione, flusilazole, prothioconazole or fludioxonil, and is prepared in clear water; the medicaments are used alternately, and one medicament is applied each time;

the concentration of the effective ingredients of the medicament in the accurate application in the step (2) is 500-1000 mg/kg;

the application time in the accurate application in the step (2) is that the application is carried out once every 15-25 d;

the concentration of the effective components of the bactericide in the step (3) is 100-250 mg/kg;

spraying the bactericide in the step (3) for 1-2 times;

and (4) spraying the bactericide in the step (3) from the initial flowering stage to the initial fruit stage of each batch of pitaya.

2. The comprehensive prevention and control method for pitaya brown rot based on precise pesticide application according to claim 1, characterized by comprising the following steps of:

the fertilizer in the step (1) comprises an organic fertilizer and a compound fertilizer;

the organic fertilizer comprises a high-quality organic fertilizer, a decomposed chicken manure fertilizer and a peanut bran fertilizer;

the compound fertilizer comprises Norwegian ternary compound fertilizer.

3. The comprehensive prevention and control method for pitaya brown rot based on precise pesticide application as claimed in claim 2, characterized in that:

the amount of the organic fertilizer is 2-5 kg of the organic fertilizer applied to the plants;

the amount of the compound fertilizer is 0.1-0.25 kg of the plant application amount.

4. The comprehensive prevention and control method for pitaya brown rot based on precise pesticide application according to claim 1, characterized by comprising the following steps of: and (4) reserving 6-10 fruit branches for each plant according to the tree vigor and the management level in the step (3).

5. The application of the pitaya brown rot comprehensive prevention and control method based on precise pesticide application in the pitaya cultivation in any one of claims 1 to 4.

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