JPWO2019239888A1 - Tea pest control method - Google Patents

Abstract

Provided is a new tea pest control method that does not use pesticides and can control tea pests more effectively. A method for controlling pests of tea, which comprises contacting tea leaves or tea plants with mixed cooling steam in which saturated steam and air are mixed at a volume ratio of 1: 1 to 1: 4.

Description

The present invention relates to a method for controlling pests of tea for exterminating or controlling pests in tea plants.

Since various pests occur in fields such as tea gardens, control of pests is indispensable for the sound cultivation of tea plants. Conventionally, tea producers have used appropriate types and amounts of chemicals at appropriate times. We have responded by spraying.

Regarding the method for controlling tea by spraying such a chemical, for example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 7-31350), in the extermination or control work of shellworms and the like adhering to branches and the like in the tea plant, the chemical is applied to the tea plant. As a device for spraying evenly and efficiently in a short time, a large number of nozzles are projected on the lower surface of a substantially arcuate substrate provided with a handle, and the chemicals are supplied to each nozzle. The spraying device is disclosed.

Further, in Patent Document 2 (Japanese Unexamined Patent Publication No. 7-289057), a plucking mechanism that is moved along a tea ridge and picks tea leaves and a drug adhering means for adhering a drug to a tea plant are integrally configured. Discloses a method for controlling pests of tea plants by a tea leaf plucking device in which a chemical adhering means attaches a chemical to the plucking cut end of the tea plant immediately after the tea leaves are picked.

By the way, control methods using chemicals such as chemical fertilizers and pesticides are concerned about adverse effects on human health and environmental pollution. Therefore, in recent years, pests and pests have been controlled with little or no chemical fertilizers or pesticides. How to do it is being considered. Especially for tea, in Japan, about 100 kinds of pesticide ingredients are currently set for tea, while in other countries, pesticide ingredients are not approved or residual pesticide standards are set extremely low. Considering the export of tea, it was urgent to consider a control method that does not use pesticides.

Regarding the control method that does not use pesticides, for example, in Patent Document 3 (Japanese Unexamined Patent Publication No. 2016-152794), warm water is sprayed on a field that has been specially maintained, and pest eggs, larvae, and adults are leaves of agricultural products. A hot water control method for controlling pests and pests is disclosed by spraying an organic farming solution on the leaf surface when the plants are attached to the plant.

In Patent Document 4 (Japanese Unexamined Patent Publication No. 2016-158522), a wetness degree sensor is provided at a position close to the parasitic environment of anaerobic pests in the field, and water is sprinkled on the field according to the detection value of the wetness degree sensor. A method for controlling a hygroscopic pest is disclosed, which is characterized in that a repellent situation of the anaerobic pest and / or a situation in which it is difficult to survive is revealed.

In Patent Document 5 (Japanese Unexamined Patent Publication No. 2011-212012), a saturated water vapor flow adjusted to a required temperature is generated in a processing space surrounding a plant seedling so as to flow horizontally on the upper side of the plant seedling. A method for controlling pests of plant seedlings is disclosed, which comprises exposing the plant seedlings to a saturated steam stream for a period of time within a range that does not cause thermal damage.

Further, in Non-Patent Document 1, when a plant such as strawberry is heated to a high temperature of 40 to 50 ° C. for several tens of seconds to several minutes, the plant causes various reactions and resistance to diseases is induced. For example, powdery mildew. It is disclosed that there is a phenomenon that makes it difficult to get sickness such as powdery mildew.

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

Tatsuo Sato "Control of plant diseases using heat shock treatment" Vegetable information. February 2013 issue

Among the long-term crops, tea is a special crop and has the characteristic of harvesting tea leaves multiple times a year. The picking time differs depending on the region. For example, in Shizuoka prefecture, after the first tea is picked between mid-April and mid-May, about 45 to 50 days have passed since the first tea was picked, and the next buds appear. It is normal to wait for the bancha to grow before picking the second tea, and then wait for about 3 months until autumn before picking the autumn / winter bancha.
In this way, for tea plants that are harvested multiple times during the year, it is necessary to control them multiple times each time they are harvested. In some cases, the pesticides sprayed on the tea leaves remained, and the types and concentrations of the pesticides contained in the tea leaves increased. In addition, since the number of times the pesticide is used increases, it may be more expensive than general crops. Therefore, there has been a demand for an effective new pest control method without using pesticides.

Therefore, the present invention is an object of providing a new tea pest control method that does not use pesticides and can control tea pests more effectively.

The present invention is characterized in that a treatment is performed in which moist 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 pest control method for tea plants.

According to the tea pest control method proposed by the present invention, tea pests can be effectively controlled by using mixed cooling steam which can be obtained by mixing saturated steam and the atmosphere without using pesticides. Can be done.

Next, the present invention will be described based on examples of embodiments. However, the present invention is not limited to the embodiments described below.

<Main control method>
In the tea pest control method (referred to as "the present control method") according to an example of the embodiment of the present invention, mixed cooling water vapor obtained by mixing saturated water vapor and the atmosphere at a volume ratio of 1: 1 to 1: 4 is used. , A method for controlling tea, which comprises performing a treatment of contacting tea leaves or tea plants.

(Target tea)
The tea targeted by this control method may be any tea that is cultivated for the purpose of extracting the plucked tea leaves or processed tea leaves into a liquid and drinking the liquid. The tea may be cultivated for the purpose of edible picked tea leaves.
Specific examples thereof include sencha, tencha, gyokuro, oolong tea, black tea, and other teas for cultivating tea for beverages.

This control method is a technique particularly suitable for large-scale production such as "tea garden". Specifically, it is a technique suitable for a tea plantation with a tea plantation area of 1 ha or more. For example, the method of showering water or spraying hot water requires spraying a large amount of water on the tea plantation, which is not only difficult in terms of equipment, but also causes moisture damage due to drainage and excessive water volume. There is a possibility that the growth of sprouts will deteriorate, the yield and quality will decrease, and the mature leaves will turn yellow and fall. On the other hand, since this control method uses water vapor, the amount of water sprayed can be suppressed as described later, and such a problem can be solved.

(Target diseases and insects)
Examples of diseases that can be targeted by this control method include charcoal disease, ring spot disease, red leaf blight, net blast disease, and white spot disease. Examples of insect-damaging insect species include Jacobiasca formidori (hereinafter referred to as planthopper), Kanzawa spider mite, scale insect, Thrips palmi Karny, Thrips palmi Karny, and Tea plant worm. However, it is not limited to these.

(Saturated water vapor)
The saturated steam may be steam produced by using arbitrary water such as tap water and well water. If necessary, it may be steam produced using water to which a drug has been added.

The 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 is 99 to 140 ° C. Among them, it is more preferable to use saturated steam at 0.1 MPa and 100 ° C.

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

(Mixed cooling steam)
It is preferable to mix the saturated steam and the atmosphere at a volume ratio of 1: 1 to 1: 4 to prepare mixed cooling steam, among which 1: 1 to 1: 3, and among them, 1: 1 to 1: 2. It is more preferable to prepare mixed cooling steam by mixing with.
The mixed cooling steam produced in this way is atomized water.

More specifically, for example, saturated steam produced in a steam boiler and air (atmosphere) taken in from the outside may be mixed in the chamber, and the pressure in the chamber is 0.1 to 1.0 MPa. Above all, it is preferable to adjust it to 0.1 or more or 0.5 or less, and among them, 0.1 or more or 0.2 or less.
By bringing the mixed cooling steam mixed in the above ratio into contact with the tea leaves or tea plants, it is possible to control diseases and pests without attaching excess water.
Compared to the control method by soaking in warm water or showering, the method of bringing the mixed cooling steam into contact with the tea leaves or tea plants causes thermal damage because it is rapidly cooled by the surrounding air after the treatment for a predetermined time. It is especially effective for easy-to-use tea sprouts and leaf edges.

(Method of bringing mixed cooling steam into contact with tea leaves or tea plants)
The mixed cooling steam is preferably brought into contact with the tea leaves on the surface portion of the leaf layer of at least the tea plant and the tea leaves, and further preferably the mixed cooling steam is brought into contact with the tea leaves on the bud portion to be plucked.
By bringing mixed cooling steam into contact with the tea leaves on the surface of the leaf layer, it is possible to control conidia and pests of diseases that exist around the buds and affect their growth and quality. In addition, the buds can be directly controlled by bringing the mixed cooling steam into contact with the tea leaves of the bud portion to be plucked.
Above all, it is preferable to bring the mixed cooling steam into contact with the cut surface of the stem, and it is preferable to bring the mixed cooling steam into contact with the young leaves in which the hair mushrooms are present. Further, it is preferable to bring the mixed cooling steam into contact with the hardened leaves below the plucked surface, which is generally called "parent leaf", and further, it is preferable to bring the mixed cooling steam into contact with the branches. It is preferable that the trunk is also brought into contact with the mixed cooling steam.
The mixed cooling steam can be effectively controlled by contacting the cut surface of the stem with the cut surface of the stem, and the anthrax can be effectively controlled by contacting the young leaves with hair mushrooms. be able to. In addition, by bringing the mixed cooling steam into contact with the parent leaves, branches, and trunks, conidia and pests adhering to them can be controlled.

The contact time for contacting the tea leaves is preferably 1 second to 10 seconds, particularly preferably 2 seconds or more or 8 seconds or less, and particularly preferably 3 seconds or more or 6 seconds or less.
The contact time refers to the time during which the mixed cooling steam contacts the tea leaves or the tea plant, in other words, the time during which the mixed cooling steam is sprayed on the same portion of the tea leaves or the tea plant, and the mixed cooling steam is particularly preferable at a predetermined temperature. 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 a spraying means is provided in the front-rear direction next to a self-propelled device such as a tractor, and the mixed cooling steam spraying device is sprayed on the tea plant while moving the self-propelled device. The passage time from the front to the rear of the tractor is the contact time of the mixed cooling steam maintained at the predetermined temperature, that is, the contact time.

As a specific means for bringing mixed cooling steam into contact with tea leaves or tea plants, for example, a self-propelled device such as a tractor is equipped with a steam boiler and a mixed cooling steam production / spraying device equipped with a chamber and spraying means, and the self-propelled device is installed. Examples thereof include a method in which a mixed cooling steam spraying device is sprayed on the tea plant while moving the mixed cooling steam to bring the mixed cooling steam into contact with the tea leaves or the tea plant. However, the method is not limited to this method.

As for the amount of the mixed cooling steam to be brought into contact with the tea leaves to the tea plant, it is preferable to bring the mixed cooling steam of 100 to 3000 L / min into contact with the tea leaves to the tea plant per ^{1 m 3, among which 120 L / min or more or 1500 L / min or less.} Among them, it is more preferable to bring the mixed cooling steam of 150 L / min or more or 1000 L / min or less into contact.

Further, 1 m ³ per tea leaves or tea tree hand, is preferably brought into contact with mixed cooling steam amount corresponding to saturated steam of 50~1000L / min, among others 160L / min or more or 800L / min or less, among them 170L / It is more preferable to contact the mixed cooling steam in an amount corresponding to saturated steam of min or more or 500 L / min or less.

Further, 1 m ³ per tea leaves or tea tree hand, it is preferably brought into contact with mixed cooling steam 20~300g as moisture content, among others 30g more or 200g or less, contacting a 40g or more, or 100g or less mixed cooling steam Among them Is even more preferable.
As described above, this control method can suppress the amount of water sprayed on the tea plantation as compared with the method of showering water or spraying hot water, so that the control method may be simple in terms of equipment. In addition, it is possible to suppress the occurrence of moisture damage due to drainage and excessive water volume, and prevent the growth of sprouts from deteriorating, so it is possible to prevent deterioration in yield and quality, and even yellowing of mature leaves. It can be suppressed.

(Pest control treatment time)
From the viewpoint of effectively controlling anthrax and ring spot disease, the above-mentioned treatment of bringing the mixed cooling steam into contact with the tea leaves (referred to as "main control treatment") is performed from the time when the tea leaves are pruned or pruned. It is preferably carried out within a week, especially within a week, and above all, within a day.

The above-mentioned plucking of tea leaves is not particularly limited as long as it is plucking for harvesting tea leaves. Above all, it is preferable to harvest the first tea or the second tea.
Further, the pruning of the tea leaves means the pruning work of the pruned surface performed after the tea leaves are pruned. Of these, pruning after pruning the first tea or pruning after pruning the second tea is preferable.

Among the above, it is preferable to apply this control treatment after the first tea is picked and before the second tea is picked. However, it may be performed before the first tea is picked, or after the second tea is picked.
Among them, it is preferable to carry out the main control treatment between the day of pruning or pruning of the first tea to 14 days, and among them, between the day of pruning or pruning to 7 days, and among them, the day of pruning or pruning to 3 days or less. It is even more preferable to carry out this control treatment.
Since the tea plant is damaged by pruning or pruning, conidia of ring spot disease may enter from the wound. Therefore, it is preferable to control the tea immediately after pruning or pruning, and it is possible to reduce conidia of anthrax before sprouting and reduce planthoppers.

Furthermore, from the viewpoint of preventing anthrax and planthoppers, the most effective second tea buds are sprouting from the first tea pruning date or the pruning date to 10 to 25 days, especially the pruning date or the pruning date. It is particularly preferable to carry out from 15 to 20 days.

On the other hand, from the viewpoint of preventing ring spot disease, the injured part by the blade of the pruning machine, which is likely to be the source of infection of ring spot disease, becomes the infected part. It is preferable to carry out within 24 hours, particularly within 18 hours, and above all, within 12 hours from the time when the tea leaves are pruned or trimmed.

<Tea production method>
Grow tea trees while applying this control method, and 2-4 of the first tea (March-May), second tea (June-July), third tea (July-August), and autumn-winter bancha (autumn) Plucking may be performed at intervals.
For example, in Kagoshima prefecture, the first tea is picked from mid-April to the end of May, and about 45 to 50 days have passed since the first tea was picked, and after waiting for the next bud to grow, the second tea is picked. It is usual that 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.

The plucked tea leaves are steamed in a rough tea factory to inactivate (blue-kill) the oxidizing enzymes contained in the fresh tea leaves, and then kneaded and dried by rough kneading, kneading, medium kneading, and fine kneading. After being processed into rough tea through the above steps, it may be further processed according to the intended use.

<Explanation of words>
When expressed as "X to Y" (X and Y are arbitrary numbers) in the present specification, unless otherwise specified, they mean "X or more and Y or less" and "preferably larger than X" or "preferably Y". It also includes the meaning of "smaller".
Further, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it means "preferably larger than X" or "preferably less than Y". Intention is also included.

Hereinafter, the present invention will be described in more 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 the atmosphere, and the control effect when the mixed cooling steam was brought into contact with tea plants and tea leaves was verified.

In the field in Shizuoka prefecture, for the tea variety "Yabukita", the mixed cooling steam shown in Table 1 is applied to tea trees and tea leaves using a commercially available nozzle (20 heads) used for tea control. On the other hand, the control treatment of spraying only the treatment time shown in Table 1 was carried out within 24 hours (June 13) after the second tea was picked.

At this time, the mixed cooling steam is a volume ratio of saturated steam at 0.1 MPa and 100 ° C. and air at 0.1 MPa and 15 ° C. produced using a commercially available boiler SB-110 (manufactured by Marubun Seisakusho) in the chamber. Mix at a ratio of 1: 1 to 1: 4, measure the temperature of the mixed gas of the steam 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.
As for the leaf surface temperature of the tea leaves, the surface temperature of the parent leaf located on the leaf layer surface was measured using an infrared radiation thermometer (SK-8700II, manufactured by Sato Keiryoki Mfg. Co., Ltd.). The same applies to the cases 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 outside air supplied into the chamber per minute. is there.
Further, as shown in Table "saturated vapor contact amount", "mixed cooling steam contact amount", "amount of water", respectively, the volume or mass per unit were injection time with respect to 1 m ³ per tea leaves to the tea plant. The same applies to the cases described later.

Then, on the third tea picking day (July 29), the presence or absence of "anthrax", "ring spot disease" and "pest" was observed, and if they did not occur, "○ (good)" was given. Judgment was made, and when the occurrence was confirmed, it was judged as "x (poor)".

<Result>
From the above examples and the test results obtained by the present invention, when the mixed cooling steam obtained by mixing saturated steam and the atmosphere at a volume ratio of 1: 1 to 1: 4 is brought into contact with tea plants and tea leaves, tea is obtained. It was found that the pests of the tea plant can be controlled.

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

In a field in Shizuoka prefecture, the mixed cooling steam produced in the same manner as in Test 1 is sprayed onto tea trees and tea leaves for the tea variety "Yabukita" for the treatment time shown in Table 2 as in Test 1. Was carried out 11 times every 10 days after the second tea was picked (June 13-October 13).
On August 22, during the treatment period, three pest traps (Bug-Scan, manufactured by Biobest, 10 cm × 13 cm) were installed in each test plot, and the traps were collected on October 13. After that, the number of pests attached to the trap was counted, and the results of verifying the pest control effect on tea plants and leaves are shown in Table 2.
As for pests, Jacobiasca foreminosa, which is a typical pest in tea leaves or tea trees, was selected, and the pest control effect was determined from the average number of Jacobiasca foreminosa attached to the three pest traps set up in each test plot. It was judged whether or not there was.

<Result>
In all the test plots where the mixed cooling steam was brought into contact with the tea trees and tea leaves, the average number of individuals of Jacobiasca fornicus was smaller than that in the test plots where the conventional control was performed. It was confirmed that the insect control effect can be obtained by bringing the mixed cooling steam obtained by mixing 1: 1 to 1: 4 into contact with the tea plant and the tea leaves.

<Test 3>
We verified the appropriate time to carry out the control treatment in which the mixed cooling steam is brought into contact with the tea leaves.

In a field in Shizuoka prefecture, mixed cooling steam obtained by mixing saturated steam and air at a volume ratio of 1: 2 for the tea variety "Yabukita" was applied to tea trees and tea leaves in the same manner as in Test 1. Within 24 hours (May 7), one-leaf stage (May 21), Mitsuha after the first tea plucking (April 23), the pest control treatment is performed for the purpose of leveling the plucked surface. It was carried out in each period (June 13th).
Then, on the day of picking the second tea (June 26), the presence or absence of "anthrax", which is more likely to occur in the second tea in Yabukita, and "ring spot disease" and "pests", which are highly sensitive to Yabukita, After observing, if each did not occur, it was judged as "○ (good)", and if it was confirmed, it was judged as "× (poor)".

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

<Result>
It was confirmed that the test groups 16 to 22 could obtain the same control effect as the conventional control of the test group 24, and that the control treatment 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 plot 23, which is an untreated plot, 90% of the 1-core 4-5 leaves, which are the second tea, were damaged by planthoppers. Therefore, the occurrence of anthrax and ring spot disease could not be confirmed directly, but the occurrence of anthrax and ring spot disease was observed at the edges of the ridges where conventional control was insufficient in the surrounding fields. It was. Considering that anthrax spreads due to the scattering of conidia due to raindrops, and ring spot disease spreads due to the dispersion of conidia due to rainfall and the adhesion of conidia to the plucking machine, the control treatment that brings mixed cooling steam into contact with the tea leaves is effective. It turned out that there was.

Next, the flow of each disease to the onset and the most preferable time for steam control were examined.
Anthrax is a disease that is transmitted from hair mushrooms on young shoots and develops after an incubation period of 14 to 20 days (8 to 15 days at the shortest) after attachment to the hair mushrooms.
It was found that such a method for controlling anthrax is most effective when the buds with hair mushrooms are in the leaf-opening stage (within two weeks after the first tea pruning or pruning).
On the other hand, ring spot disease is a disease that is mainly transmitted from the injured surface at the time of plucking. Conidia germinate 2-3 hours after attachment and develop after an incubation period of 5-10 days. In the conventional conventional control, it is necessary to control (spray the chemicals) within one day after pest control, and it has been said that the effect decreases as the period increases.
It can be considered that the control of ring spot disease is most effective within one day after pruning or pruning.
Since planthoppers suck only young shoots, it is most effective to perform them during the leaf opening period (within two weeks after the first tea is picked).

The control treatment in which the mixed cooling steam is brought into contact with the tea leaves or tea plants is effective even if it is performed outside the above period (test plots 17, 18, etc.), and these can be considered as follows.
Agricultural chemicals are roughly divided into "preventive agents" and "therapeutic agents". Within one day from the above-mentioned plucking and within two weeks from the first tea, both aim at "prevention", and it is based on the idea that prevention of the onset of disease leads to obtaining good quality tea leaves. However, since the disease may develop even if the control is performed, a therapeutic agent is used in the conventional control, but the pesticide is used at a clearly determined time, and the preventive agent is generally a therapeutic agent up to 30 days before the second tea is plucked. Can generally only be used up to 14 days before the second tea is picked. Therefore, until now, pesticides could not be sprayed before a certain period of plucking, and the disease had spread. However, according to the control treatment in which the mixed cooling steam is brought into contact with the tea leaves or tea plants, pesticides are not used, so that the treatment can be performed at a required time.

<Test 4>
During the sprouting period of No. 1 tea, which is the most vulnerable to the external environment, mixed cooling steam was sprayed on the tea plants to verify the conditions that did not cause heat damage.

In a field in Shizuoka prefecture, for the tea variety "Yabukita", use a commercially available nozzle (20 heads) used for tea control with mixed cooling steam for tea trees and tea leaves for 3 to 10 seconds. It was sprayed and the presence or absence of thermal damage was observed.

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

As for the leaf surface temperature of the tea leaves, the surface temperature of the parent leaf located on the leaf layer surface was measured using an infrared radiation thermometer (SK-8700II, manufactured by Sato Keiryoki Mfg. Co., Ltd.).
The presence or absence of thermal injury is determined by the presence or absence of thermal injury when it is observed that the leaves have fallen without progressing, such as the leaves falling to melt or the leaves turning red and black and falling off. If such a condition is observed only in a part, it is judged that there is a thermal injury, and if such a condition is not observed anywhere, it is judged that there is no thermal injury. did.

<Result>
When saturated steam and the atmosphere were brought into contact with mixed cooling steam mixed at a volume ratio of 1: 1 to 1: 4, thermal damage did not occur even when exposed for a long time (10 seconds). When saturated steam and mixed cooling steam in which the atmosphere was mixed at a volume ratio of 1: 1 were brought into contact with each other, partial thermal injury occurred in 10 seconds. Further, since the mixed cooling steam mixed at a volume ratio of 1: 0.8 exceeds 60 ° C., thermal damage occurs in a shorter time.

Claims (7)

A method for controlling pests of tea, which comprises a treatment in which moist 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. .. The method for controlling tea pests according to claim 1, wherein the tea leaves or tea plants per 1 m ³ are brought into contact with mixed cooling steam in an amount corresponding to saturated steam of 50 to 1000 L / min. The method for controlling pests of tea according to claim 1 or 2, wherein 100 to 3000 L / min of mixed cooling steam is brought into contact with tea leaves or tea plants per 1 m ^3. 1 m ³ per tea leaves or tea tree to, pest control method of tea according to claim 1, wherein contacting the mixture cooled steam 20~300g as moisture content. The method for controlling pests of tea according to any one of claims 1 to 4, wherein the time for contacting the mixed cooling steam with the tea leaves or tea plants is 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 cooled steam into contact with tea leaves or tea plants is performed twice or more every 1 to 14 days. A method for producing tea, which comprises subjecting a mixed cooling steam obtained by mixing saturated steam and the atmosphere at a volume ratio of 1: 1 to 1: 4 into contact with tea leaves or tea plants.