WO2019239888A1

WO2019239888A1 - Method for controlling diseases and pests in tea

Info

Publication number: WO2019239888A1
Application number: PCT/JP2019/021198
Authority: WO
Inventors: 耕司石上; 光吉田
Original assignee: 株式会社伊藤園
Priority date: 2018-06-15
Filing date: 2019-05-29
Publication date: 2019-12-19
Also published as: JP7065182B2; JPWO2019239888A1

Abstract

A novel method is provided for controlling diseases and pests in tea without using chemicals, with which it is possible to more effectively control diseases and pests in tea. The method for controlling diseases and pests in tea is characterized by comprising a process for bringing a mixed cooling water vapor into contact with tea leaves and plants, the mixed cooling water vapor obtained by mixing saturated steam and air in a volume ratio of 1:1 to 1:4.

Description

Tea pest control method

The present invention relates to a tea pest control method for controlling or controlling pests in tea plants.

Since various pests occur in fields such as tea gardens, pest control is indispensable for healthy cultivation of tea trees. Traditionally, tea producers have appropriate types and amounts of drugs at appropriate times. It has been dealt with by spraying.

With regard to a method for controlling tea by spraying such a chemical, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 7-31350), in the control or control work of shellworms attached to branches or the like in a tea tree, the drug is introduced into the tea tree. As a device for spraying evenly and efficiently in a short time, a large number of nozzles project from the lower surface of a substantially arc-shaped substrate with a handle, and the drug is supplied to each nozzle. A spraying device is disclosed.

Patent Document 2 (Japanese Patent Application Laid-Open No. 7-289057) discloses that a plucking mechanism that moves along a teacup and picks tea leaves and a medicine adhering means that attaches the medicine to the tea tree are configured integrally. Discloses a method for controlling pests of tea trees by means of a tea leaf plucking device in which a drug attaching means attaches a drug to a plucking cut of tea trees immediately after plucking the tea leaves.

By the way, control methods using chemicals such as chemical fertilizers and pesticides are concerned with adverse effects on human health and environmental pollution. Therefore, in recent years, pest control has been controlled with little or no use of chemical fertilizers and pesticides. How to do is being studied. Especially for tea, about 100 kinds of pesticide ingredients are currently set for tea in Japan, while in other countries, pesticide ingredients are not approved or the residue pesticide standards are set very low. In many cases, considering the export of tea, there was an urgent need to consider a pesticide-free control method.

Regarding control methods that do not use pesticides, for example, in Patent Document 3 (Japanese Patent Laid-Open No. 2016-152794), hot water is sprayed on specially prepared fields, and pest eggs, larvae, and adults are removed from crops. A hot water control method for controlling pests and insects by spraying a solution for organic farming on the leaf surface when adhering to water is disclosed.

Patent Document 4 (Japanese Patent Application Laid-Open No. 2016-158522) provides a wetness degree sensor at a position close to the parasitic environment of an anaerobic pest in the field, and waters the field according to the detection value of the wetness degree sensor. There is disclosed a method for controlling an anaerobic pest characterized by revealing a repellent situation of an anaerobic pest and / or a situation where it is difficult to survive.

In Patent Document 5 (Japanese Patent Application Laid-Open No. 2011-212012), a saturated water vapor flow adjusted to a required temperature is generated in a treatment space surrounding a plant seedling so as to flow horizontally above the plant seedling, There is disclosed a method for controlling pests of plant seedlings, wherein the plant seedlings are exposed to a saturated steam flow for a time within a range not subject to thermal injury.

In Non-Patent Document 1, when a plant such as a strawberry is heated to a high temperature of 40 to 50 ° C. for several tens of seconds to several minutes, the plant undergoes various reactions and induces resistance to diseases, such as udon. It is disclosed that there is a phenomenon that makes it difficult to get sick such as gonorrhea.

Japanese Unexamined Patent Publication No. 7-31350 JP-A-7-289057 Japanese Unexamined Patent Publication No. 2016-152794 Japanese Unexamined Patent Publication No. 2016-158522 JP 2011-212012 A1

Among the perennial crops, tea is a special crop and has the characteristic of harvesting tea leaves multiple times a year. The picking time varies depending on the region. For example, in Shizuoka Prefecture, after the first tea was picked between mid-April and mid-May, 45-50 days after the first tea picking, the next buds It is normal to wait for the tea to grow and then pluck the second tea, and then wait about three months until autumn before plucking the autumn / winter bancha.
In this way, for tea trees that are harvested multiple times during the year, it is necessary to carry out control several times for each harvesting period. In some cases, the pesticides sprayed on the tea leaves remained and the type and concentration of the pesticides contained in the tea leaves increased. Moreover, since the frequency | count of the use of an agrochemical increases, it may be expensive compared with a common crop. Therefore, an effective new method for controlling pests without using pesticides has been demanded.

Therefore, the present invention is a tea pest control method that does not use pesticides, and is intended to provide a new tea pest control method that can more effectively control tea pests.

The present invention is a tea characterized in that wet air (referred to as “mixed cooling steam”) in which saturated steam and air are mixed at a volume ratio of 1: 1 to 1: 4 is brought into contact with tea leaves or tea plants. We propose a method for controlling pests.

According to the tea pest control method proposed by the present invention, it is possible to effectively control tea pests using mixed cooling steam that can be obtained by mixing saturated steam and the atmosphere without using pesticides. Can do.

Next, the present invention will be described based on an embodiment. However, the present invention is not limited to the embodiment described below.

<This control method>
A method for controlling pests of tea according to an example of an embodiment of the present invention (referred to as “the present control method”) uses mixed cooling steam obtained by mixing saturated steam and air in a volume ratio of 1: 1 to 1: 4. A method for controlling tea, characterized by performing a treatment of bringing into contact with tea leaves or tea trees.

(Target tea)
The tea targeted by this control method may be any tea that is cultivated for the purpose of extracting the picked tea leaves or processed tea leaves into a liquid and drinking the liquid. Tea cultivated for the purpose of eating edible tea leaves may also be used.
Specifically, for example, tea cultivating sencha, strawberry tea, gyokuro, oolong tea, black tea, and other tea for beverages can be mentioned.

This control method is a technology especially suitable for large-scale production such as “tea garden”. Specifically, this is a technique suitable for a tea garden having a tea garden area of 1 ha or more. For example, in the method of showering water or spraying hot water, a large amount of water is sprayed on the tea plantation, which is not only difficult in terms of equipment, but also causes drainage and excessive water damage, The growth of new shoots will deteriorate, yield and quality will both decline, and adult leaves may become yellowed and fallen. On the other hand, since this prevention | control method uses water vapor | steam, it can suppress the spraying quantity of water so that it may mention later, and can solve this subject.

(Target disease and insect damage)
Examples of diseases that can be targeted by the present control method include anthracnose, ring spot disease, leaf blight, net blast, and leprosy. Examples of insect pests include Chanomidori Himekobai (hereinafter referred to as “Unka”), Kanzawa spider mite, stag beetle, chanterelle thrips, chinook cricket, chanohosoga and the like. However, it is not limited to these.

(Saturated water vapor)
The saturated water vapor may be water vapor produced using any water such as tap water and well water. If necessary, it may be water vapor prepared using water to which a drug is added.

Saturated steam can be produced by a commercially available steam boiler, and it is preferable to use saturated steam at 0.1 to 1.0 MPa and 98 to 180 ° C., among which 0.1 to 0.5 MPa at 99 to 140 ° C., Among them, it is more preferable to use saturated water vapor at 100 ° C. at 0.1 MPa.

(atmosphere)
The atmosphere may be normal air, and the temperature of the atmosphere may change depending on the temperature. This is because the temperature of the mixed cooling water vapor can be adjusted by adjusting the mixing ratio of the saturated water vapor and the atmosphere.

(Mixed cooling steam)
The saturated water vapor and the air are preferably mixed at a volume ratio of 1: 1 to 1: 4 to prepare a mixed cooling water vapor, preferably 1: 1 to 1: 3, more preferably 1: 1 to 1: 2. It is more preferable that the mixed cooling water vapor is produced by mixing with the above.
The mixed cooling water vapor produced in this way is mist-like water.

More specifically, for example, saturated water vapor produced with a steam boiler and air (atmosphere) taken from the outside may be mixed in the chamber, and the pressure in the chamber is 0.1 to 1.0 MPa, Among these, it is preferable to adjust to 0.1 or more and 0.5 or less, and in particular, to 0.1 or more and 0.2 or less.
By bringing the mixed cooling water vapor mixed at the above ratio into contact with tea leaves or tea trees, it becomes possible to control diseases and pests without attaching excessive moisture.
The method of bringing mixed cooling water vapor into contact with tea leaves or tea trees is rapidly cooled by the surrounding air after a predetermined time treatment, compared with the control method by soaking in hot water or showering, causing thermal injury. It is particularly effective for tea shoots and leaf edges that are easy to break.

(Method of bringing mixed cooling water vapor to tea leaves or tea trees)
The mixed cooling steam is preferably brought into contact with tea leaves on the surface of the leaf layer of at least tea plant and tea leaves, and more preferably, the mixed cooling steam is brought into contact with tea leaves in the bud part to be picked.
By bringing mixed cooling water vapor into contact with the tea leaves on the surface of the leaf layer, it is possible to control the conidia and pests that are present around the bud and affect the growth and quality of the disease. Moreover, buds can be controlled directly by bringing mixed cooling water vapor into contact with the tea leaves of the buds to be plucked.
Among them, it is preferable to bring the mixed cooling water vapor into contact with the cut surface of the stem, and it is preferable to bring the mixed cooling water vapor into contact with the young leaves where the hair follicles exist. Further, it is preferable that the mixed cooling water vapor is also contacted with the hardened leaf below the plucked surface generally referred to as “parent leaf”, and it is further preferable that the mixed cooling water vapor is contacted with the branch. It is preferable to bring mixed cooling water vapor into contact with the trunk.
It is possible to effectively control ring rot by bringing mixed cooling water vapor into contact with the cut surface of the stem, and effectively controlling anthracnose by bringing it into contact with young leaves with hair follicles. be able to. In addition, the mixed cooling water vapor is brought into contact with the parent leaves, branches, and trunks, so that conidia and pests attached thereto can be controlled.

The contact time for contacting the tea leaves is preferably 1 to 10 seconds, more preferably 2 seconds or more and 8 seconds or less, and particularly preferably 3 seconds or more and 6 seconds or less.
The contact time refers to the time during which the mixed cooling water vapor contacts the tea leaf or tea tree, in other words, the time during which the mixed cooling water vapor is sprayed on the same location of the tea leaf or tea tree. For example, it means the time of contact with tea leaves or tea plants at 45 to 55 ° C.
For example, as described below, when spraying means is provided across the side of a self-propelled device such as a tractor, and the mixed cooling water vapor spraying device is sprayed on tea trees while moving the self-propelled device In this case, the passage time from the front to the rear of the tractor is the time when the mixed cooling steam maintained at the predetermined temperature comes into contact, that is, the contact time.

As specific means for bringing the mixed cooling water vapor into contact with tea leaves or tea trees, for example, a self-propelled device such as a tractor is equipped with a mixed cooling water vapor production and distribution device equipped with a steam boiler, a chamber and a spraying means. A method of spraying a mixed cooling water vapor spraying device on the tea tree while moving it and bringing the mixed cooling water vapor into contact with tea leaves or tea trees can be mentioned. However, it is not limited to such a method.

The amount of mixed cooling water vapor contacted with tea leaves or tea trees is preferably 100 to 3000 L / min of mixed cooling water vapor per 1 m ³ , particularly 120 L / min or more or 1500 L / min or less. Of these, it is more preferable to contact 150 L / min or more or 1000 L / min or less of mixed cooling water vapor.

Further, it is preferable to contact mixed cooling water vapor in an amount corresponding to saturated water vapor of 50 to 1000 L / min to tea leaves or tea trees per 1 m ³ , particularly 160 L / min or more or 800 L / min or less, and particularly 170 L / min. It is more preferable to contact the mixed cooling water vapor in an amount corresponding to saturated water vapor of min or more or 500 L / min or less.

Further, it is preferable that 20 to 300 g of mixed cooling steam is brought into contact with tea leaves or tea trees per 1 m ³ , particularly 30 g or more or 200 g or less, particularly 40 g or more or 100 g or less of mixed cooling steam. Is more preferable.
As described above, the present control method can suppress the amount of water sprayed on the tea garden as compared to the method of showering water or spraying hot water, so that the facility can be simple. Or, it can prevent the occurrence of moisture damage due to drainage and excessive water volume, and prevent the growth of new shoots, thus preventing decline in yield and quality. Can be suppressed.

(Control time)
From the viewpoint of effectively controlling anthracnose, ring spot disease, etc., the above-mentioned treatment of bringing mixed cooling water vapor into contact with tea leaves (referred to as “main control treatment”) is performed from the time of plucking or branching tea leaves. It is preferable to carry out within one week, particularly within one week, and within one day.

The tea leaf plucking is not particularly limited as long as it is plucking for harvesting tea leaves. Especially, it is preferable that it is plucking for harvesting the first tea or the second tea.
In addition, the branching of the tea leaves means a pruning operation of the plucked surface performed after plucking the tea leaves. Among them, the branching after the first tea picking or the branching after the second tea picking is preferable.

Among these, it is preferable to apply the present control treatment after plucking the first tea and before plucking the second tea. However, it may be performed before plucking the first tea or after plucking the second tea.
Among them, it is preferable to carry out the present pest control treatment between the day 1 of picking or the day of branching and the day of branching to 14 days, among which the day of picking or branching day to day 7 and the day of picking or branching day to day 3 or less It is even more preferable to carry out this control treatment.
Since the tea tree is damaged by plucking or pruning, conidia or the like of ring spot disease may enter from the wound. Therefore, it is preferable to control immediately after plucking or branching tea, and it is possible to reduce the conidia of the anthracnose before germination and to reduce the planthopper.

Furthermore, from the viewpoint of preventing the occurrence of anthracnose and planthopper etc., the most effective second tea buds are cultivated for 10 to 25 days from the date of first tea picking or branching, and in particular the day of picking or branching. It is particularly preferred to carry out between 15 and 20 days.

On the other hand, from the viewpoint of preventing ring disease, since the wounded part by the blade of the plucking machine that tends to become an infection source of ring spot disease becomes an infected part, the above process, that is, the process of bringing mixed cooling water vapor into contact with the tea leaves, It is preferable to carry out within 24 hours, especially within 18 hours, especially within 12 hours from the time of plucking or branching tea leaves.

<Tea production method>
Tea plants are grown while applying this control method, and 2-4 of the first tea (March to May), Nibancha (June to July), Sanbancha (July to August), and fall / winter bancha (autumn) Plucking may be performed at intervals and intervals.
For example, in Kagoshima Prefecture, the first tea is picked from mid-April to late May. Wait 45-50 days after picking the first tea and wait for the next bud to grow before serving the second tea. In general, the third tea is picked 40 to 45 days after the second tea is picked, and the fourth tea is picked 50 to 60 days after the third tea is picked.

A series of picked tea leaves are steamed with steam to inactivate (kill blue) the oxidase contained in fresh tea leaves, and then infused and dried with coarse koji, bonito, medium-plumbing, and spirits. After being processed into crude tea through the above process, it may be further processed according to the application.

<Explanation of words>
In the present specification, when expressed as “X to Y” (X and Y are arbitrary numbers), “X is preferably greater than X” or “preferably Y”, with the meaning of “X to Y” unless otherwise specified. It also includes the meaning of “smaller”.
In addition, when expressed as “X or more” (X is an arbitrary number) or “Y or less” (Y is an arbitrary number), it is “preferably greater than X” or “preferably less than Y”. Includes intentions.

Hereinafter, the present invention will be described in further detail based on the following examples and comparative examples.

<Test 1>
Mixed cooling steam was prepared by changing the mixing ratio of saturated steam and air, and the control effect when the mixed cooling steam was brought into contact with tea trees and tea leaves was verified.

In a field in Shizuoka Prefecture, for the tea variety “Yabukita”, the mixed cooling water vapor shown in Table 1 was used for tea trees and tea leaves using a commercially available nozzle (20 heads) that uses mixed cooling water vapor for tea control. On the other hand, the control process which inject | pours only the processing time shown in Table 1 was implemented within 24 hours (June 13) after the 2nd tea picking.

At this time, the mixed cooling water vapor is a saturated water vapor of 0.1 MPa and 100 ° C. prepared using a commercially available boiler SB-110 (manufactured by Marubun Seisakusho) and an atmosphere of 15 ° C. and 0.1 MPa in a volume ratio in the chamber. Mix at a ratio of 1: 1 to 1: 4, measure the temperature of the gas mixture in the vapor atmosphere discharged from the nozzle, and adjust the amount of air taken in by the mixer based on the measured temperature to achieve the desired mixing Cooled steam was obtained.
The leaf surface temperature of the tea leaf was measured by using an infrared radiation thermometer (SK-8700II, manufactured by Sato Keiki Seisakusho Co., Ltd.) and the surface temperature of the parent leaf located on the leaf layer surface. The same applies to the case described later.

The “saturated water vapor amount (L / min)” and “outside air amount (L / min)” shown in the table are the amounts of 0.1 MPa (atmospheric pressure) saturated water vapor and atmospheric air supplied into the chamber per minute. is there.
The “saturated water vapor contact amount”, “mixed cooling water vapor contact amount”, and “water content” shown in the table are the volume or mass per unit time sprayed on tea leaves or tea trees per 1 m ³ , respectively. The same applies to the case described later.

Then, on the day of picking the third tea (July 29), the occurrence of “anchovy”, “ringhole disease” and “pest” was observed. When the occurrence was confirmed, it was determined as “× (poor)”.

<Result>
From the above examples and test results carried out by the present invention until now, when mixed cooling water vapor obtained by mixing saturated water vapor and air at a volume ratio of 1: 1 to 1: 4 is brought into contact with tea tree and tea leaves, It was found that pests can be controlled.

<Test 2>
Mixed cooling steam was produced by changing the mixing ratio of saturated steam and air, and the relationship between the treatment frequency when the mixed cooling steam was brought into contact with tea trees and tea leaves and the pest control effect was verified.

In a field in Shizuoka Prefecture, a mixed cooling steam produced in the same manner as in Test 1 is sprayed on tea cultivar “Yabukita” to tea trees and tea leaves for the processing time shown in Table 2 as in Test 1. Was carried out a total of 11 times every 10 days after the second tea was picked (June 13 to October 13).
Three insect pest traps (Bug-Scan, manufactured by Biobest, 10 cm × 13 cm) were placed in each test section on August 22 during the treatment period, and collected on October 13. Table 2 shows the results of counting the number of pests adhering to the trap and verifying the effect of controlling pests on tea plants or tea leaves.
As for the pests, the pesticide that is a representative pest in tea leaves or tea trees is selected, and the pest control effect is determined from the average number of the pesticides attached to the three pest traps installed in each test area. The presence or absence of was judged.

<Result>
In all the test plots where mixed cooling steam was brought into contact with the tea tree and tea leaves, the average population of Chanomidorihimebikobai was lower than that in the test plots where customary control was carried out. It was confirmed that the insect-repellent effect was obtained by bringing mixed cooling water vapor obtained by mixing 1: 1 to 1: 4 into tea tree and tea leaves.

<Test 3>
It verified about the suitable time which implements the prevention process which makes mixed cooling steam contact with a tea leaf.

In the field in Shizuoka Prefecture, mixed cooling water vapor obtained by mixing saturated water vapor and air at a volume ratio of 1: 2 for tea variety “Yabukita” was applied to tea trees and tea leaves in the same manner as in Test 1. Within 24 hours (May 7) after the pruning for the purpose of leveling the plucked surface after the first tea plucking (April 23), the first leaf stage (May 21), Miba Each period (June 13) was implemented.
In addition, on the date of picking the second tea (June 26), the presence or absence of the occurrence of “anchovy” that is likely to occur in second tea in Yabukita, “ring spot disease” and “pest” that are more susceptible to Yabukita When observed, it was determined as “good” when they did not occur, and “× (poor)” when occurrence was confirmed.

The mixed cooling water vapor is a saturated water vapor of 0.1 MPa and 100 ° C. produced using a commercially available boiler SB-110 (manufactured by Marubun Seisakusho) and an atmosphere of 0.1 ° C. and 10 ° C. in a volume ratio in the chamber. It was prepared by mixing at a ratio of 1: 2.

<Result>
The test groups 16 to 22 were able to obtain a control effect equivalent to the conventional control of the test group 24, and it was confirmed that the control process in which the mixed cooling steam was brought into contact with the tea leaves was effective at any time.
On the other hand, in the test zone 23, which is an untreated zone, the damage of the leafhopper was remarkable in 1 core 4 to 5 leaves, which is the second tea, and 90% was damaged. For this reason, the occurrence of anthracnose and ring spot disease could not be confirmed directly, but anthracnose and ring spot disease were observed at the edge of the fence, where conventional control was insufficient in the surrounding fields. It was. Considering that anthracnose spreads conidia due to raindrops, and ring spot disease spreads by conidial dispersion due to rainfall and conidia adhering to a plucking machine, control treatment that makes mixed cooling water vapor contact with tea leaves is effective. I found out.

Next, the flow until the onset of each disease and the time when steam control is most preferable were examined.
Anthracnose is a disease that infects hair follicles in young buds, and develops after an incubation period of 14 to 20 days (8 to 15 days at the shortest) after attachment to hair follicles.
It has been found that such an anthracnose control method is most effective when it is carried out at the leaf opening stage of the buds with hair folds (within 2 weeks from the most tea picking or branching).
On the other hand, ring spot disease is a disease mainly transmitted from the wound surface at the time of plucking. Conidia germinate 2 to 3 hours after attachment, and become ill after a incubation period of 5 to 10 days. In conventional practice control, it is necessary to control (spray medicine) within 1 day after plucking, and it has been said that the effect decreases as the period increases.
It can be considered that it is most effective to control ring rot disease within one day after plucking or pruning.
Since the planthopper sucks only young shoots, it is most effective to do it during the bud opening stage (within 2 weeks from the first tea harvest).

The control treatment of bringing the mixed cooling water vapor into contact with tea leaves or tea trees is effective even when performed outside the above period (such as the test sections 17 and 18), and these can be considered as follows.
Pesticides can be broadly distributed with “preventive agents” and “therapeutic agents”. Within one day from the above plucking, within two weeks from the first tea, etc. are all aimed at “prevention”, and it is based on the idea that prevention of disease leads to obtaining good quality tea leaves. However, even if pest control can cause disease, therapeutic agents are used in conventional pest control, but pesticides are used for a specific period of time, and the preventive agent is generally a therapeutic agent up to 30 days before the second tea extraction. Can generally only be used up to 14 days prior to picking Nibancha. For this reason, until a certain period before plucking, pesticides could not be sprayed and the disease spread. However, according to the control treatment in which the mixed cooling water vapor is brought into contact with tea leaves or tea trees, since no agricultural chemical is used, the treatment can be performed at a necessary time.

<Test 4>
Mixed cooling water vapor was sprayed on the tea plant during the germination period of No. 1 tea, which is the most vulnerable to the external environment, and the conditions that did not cause thermal injury were verified.

In a field in Shizuoka Prefecture, for tea varieties “Yabukita”, using a commercially available nozzle (20 heads) that uses mixed cooling steam for tea control, for 3 to 10 seconds against tea trees and tea leaves The jet was sprayed and observed for thermal injury.

At this time, as shown in Table 4 below, the mixed cooling water vapor is a saturated water vapor of 0.1 MPa and 100 ° C. generated using a commercially available boiler SB-110 (manufactured by Marubun Seisakusho), and an air of 10 ° C. at 0.1 MPa. Were mixed in the chamber at a volume ratio of 1: 1 to 1: 4. The temperature of the gas mixture in the vapor atmosphere discharged from the nozzle was measured, and the amount of atmospheric air taken in by the mixer was adjusted based on the measured temperature to obtain the desired mixed cooling water vapor.

The leaf surface temperature of the tea leaf was measured by using an infrared radiation thermometer (SK-8700II, manufactured by Sato Keiki Seisakusho Co., Ltd.) and the surface temperature of the parent leaf located on the leaf layer surface.
The determination of the presence or absence of thermal injury is based on thermal injury if there is a state in which the leaf has fallen without progressing, such as the leaf falling so that it melts or the leaf turns red and black. If such a state is observed only in a part, it is determined that there is a thermal injury “partial”, and if such a state is not observed anywhere, it is determined that there is no thermal injury. did.

<Result>
When contacted with mixed cooling water vapor in which saturated water vapor and air were mixed at a volume ratio of 1: 1 to 1: 4, no thermal injury occurred even when applied for a long time (10 seconds). When the mixed cooling water vapor in which the saturated water vapor and the atmosphere were mixed at a volume ratio of 1: 1 was brought into contact, a partial thermal injury occurred in 10 seconds. Moreover, since the mixed cooling water vapor mixed at a volume ratio of 1: 0.8 exceeded 60 ° C., thermal injury occurred in a shorter time.

Claims

A method for controlling pests of tea, characterized by performing a treatment in which wet air (referred to as “mixed cooling steam”) in which saturated steam and air are mixed at a volume ratio of 1: 1 to 1: 4 is brought into contact with tea leaves or tea trees. .
The method for controlling pests of tea according to claim 1, wherein mixed cooling water vapor in an amount corresponding to 50 to 1000 L / min of saturated water vapor is brought into contact with tea leaves or tea trees per 1 m 3 .
The method for controlling pests of tea according to claim 1 or 2, wherein 100 to 3000 L / min of mixed cooling water vapor is brought into contact with tea leaves or tea trees per 1 m 3 .
4. The method for controlling pests of tea according to claim 1, wherein 20 to 300 g of mixed cooling steam is brought into contact with tea leaves or tea trees per 1 m 3 .
The method for controlling pests of tea according to any one of claims 1 to 4, wherein the mixed cooling water vapor is brought into contact with tea leaves or tea trees for 1 to 6 seconds.
The method for controlling pests of tea according to any one of claims 1 to 5, wherein the treatment of bringing the mixed cooling water vapor into contact with tea leaves or tea trees is performed twice or more every 1 to 14 days.
A method for producing tea, characterized in that a mixed cooling steam obtained by mixing saturated steam and air in a volume ratio of 1: 1 to 1: 4 is brought into contact with tea leaves or tea plants.