JP4988643B2 - Lighting device for plant disease control - Google Patents

Description

  The present invention relates to a plant disease control lighting device for controlling plant diseases such as agricultural crops.

  Conventionally, mainly for a completely closed type plant seedling production system, a plant growing lighting device that suppresses generation of algae and mold generated on a culture medium by irradiating the plant seedling with B-region ultraviolet rays (UV-B). Is known (see, for example, Patent Document 1).

Although UV-B irradiation to plants is effective for controlling plant diseases, when the amount of solar radiation per day is small, the plant body is less resistant to UV rays and is susceptible to leaf burning due to UV irradiation. Become.
JP 2003-339236 A

  An object of the present invention is to solve the above-mentioned problems and to prevent leaf burning caused by ultraviolet irradiation in a plant disease controlling lighting apparatus that controls plant diseases by ultraviolet irradiation.

  In order to achieve the above object, an invention according to claim 1 is directed to an artificial light source that emits ultraviolet light having a wavelength range of 280 to 340 nm as a main wavelength, a control unit that controls lighting of the artificial light source, and a wavelength range of 380 to 780 nm. An illuminating device for controlling plant diseases comprising an external light sensor for measuring light intensity, wherein the control unit turns off the artificial light source when the illuminance measured by the external light sensor is approximately 1000 lux or less It is.

  The invention described in claim 2 is the lighting device for controlling plant diseases according to claim 1, further comprising an auxiliary light source for irradiating light in a wavelength range of 400 to 700 nm, wherein the control unit is measured by the external light sensor. When the illuminance is about 1000 lux or less, the auxiliary light source is turned on so that the illuminance on the plant is about 1000 lux or more.

The invention according to claim 3 further includes an ultraviolet intensity meter for measuring ultraviolet radiation of 280 to 315 nm wavelength range ultraviolet (UV-B) in the plant disease control lighting device according to claim 1, wherein the control unit If the integrated light quantity of the external light of the previous day measured by the external light sensor is approximately 12000 lux · hour or less, the integrated irradiation dose of UV-B on the day measured by the ultraviolet intensity meter is 0.2 kJm ⁻² The artificial light source is controlled to be turned on so that it is not less than day ^{−1 and not} more than 8 kJm ⁻² day ⁻¹ .

  According to the first aspect of the present invention, when the illuminance is about 1000 lux or less at which the resistance of the plant to the ultraviolet ray is low, the artificial light source is turned off and the ultraviolet ray is not irradiated, so that the leaf burn of the plant can be prevented.

  According to the invention described in claim 2, since the auxiliary light source is controlled so that the illuminance on the plant is approximately 1000 lux or more, the resistance of the plant to the ultraviolet rays is ensured and the ultraviolet irradiation schedule is observed. Therefore, the efficiency of plant disease control can be improved.

  According to the invention described in claim 3, on the next day, etc., when the cloudy weather continues to rain throughout the day, the resistance of the plant to ultraviolet rays (UV-B) is weakened, and leaf burn symptoms However, since the cumulative irradiation amount of UV-B is controlled by controlling the lighting of the artificial light source, the plant disease control effect can be maintained while preventing the leaf burn of the plant.

  Hereinafter, a plant disease control lighting device (hereinafter referred to as the present lighting device) according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a configuration of the present lighting device 10 installed in an agricultural greenhouse 20. The illuminating device 10 measures an artificial light source 11 that emits ultraviolet light having a wavelength range of 280 to 340 nm as a main wavelength, a control unit 12 that controls lighting of the artificial light source 11, and an external light intensity (illuminance) in a wavelength range of 380 to 780 nm. An external light sensor 13, an auxiliary light source 14 that irradiates light in a wavelength range of 400 to 700 nm, and an ultraviolet intensity meter 15 that measures UV-B ultraviolet radiation.

  The artificial light source 11 may be of any light source type as long as the emitted light includes light in the wavelength range of 280 to 340 nm. Examples of the light source are a fluorescent lamp, a compact fluorescent lamp, a cold cathode fluorescent lamp, a xenon lamp, a high-intensity discharge lamp, a light emitting diode (LED), and an organic EL. The artificial light source 11 is provided with devices such as a lighting starter, a ballast, and a power circuit for stably illuminating the light source. The auxiliary light source 14 may be of any light source type as long as the emitted light includes light in the wavelength range of 400 to 700 nm. The wavelength range of 400 to 700 nm is an absorption wavelength range of chlorophyll, and is included in the wavelength range of visible light (about 350 to 800 nm).

  The control unit 12 is stored in, for example, a box provided at a position independent of the artificial light source 11, and is connected to the external light sensor 13, the artificial light source 11 and the like by a cable or wirelessly. The control unit 12 may be configured integrally with the artificial light source 11, the auxiliary light source 14, the external light sensor 13, or the ultraviolet intensity meter 15.

An outside light sensor is a device that measures the amount of light (illuminance) having a spectral sensitivity that is generally matched to the wavelength perceived by a person, a light receiving unit that transmits a signal in response to light, The main body unit receives a signal, converts it into numerical data, and displays the numerical value. The spectral sensitivity of the light receiving portion of the external light sensor 13 does not need to match the spectral sensitivity of the human eye, and the photosynthetic sensitivity felt by plants in the wavelength range of 400 to 700 nm (unit: “μmol · m ⁻² S ^−1). )) Or irradiance within the range (the unit is “Wm ⁻² ”).

  The ultraviolet intensity meter is generally used for measuring ultraviolet radiation (UV) having a wavelength in the range of 100 to 400 nm, and has a spectral sensitivity peak in a range obtained by subdividing the wavelength range of 100 to 400 nm into three, The amount of radiant energy per unit area within this range is measured. Regarding the subdivision of the UV wavelength region, 315 to 400 nm is referred to as UV-A, 280 to 315 nm is referred to as UV-B, and 100 to 280 nm is referred to as UV-C. In the demonstration test of the present invention, measurement was performed using a UV-B ultraviolet intensity meter (UVR-3036 / S2 manufactured by Clinical Supply) as the ultraviolet intensity meter 15.

  It is desirable that the height of the external light sensor 13 and the ultraviolet intensity meter 15 is raised or lowered depending on the growth of the target plant. It may be fixed to the average height of the crown surface until it is shipped.

  Regarding the number of ultraviolet intensity meters 15, one ultraviolet intensity meter 15 is installed in the irradiation area of one artificial light source 11, and the light output and light of the artificial light source 11 are changed according to the ultraviolet intensity received by each ultraviolet intensity meter 15. Although it is desirable to perform lighting control of the irradiation time, at least one unit may be installed in one agricultural greenhouse, and lighting control may be performed based on the value of the ultraviolet intensity meter 15 that represents the cultivation area. The number of external light sensors 13 may be one or more.

In the present lighting device 10 configured as described above, the external light sensor 13 measures the light intensity of sunlight. The control unit 12 receives a real-time measurement value sent from the external light sensor 13 as input, and controls the artificial light source 11 to be turned on when the measurement value is larger than the threshold, and to turn off the artificial light source 11 when the measurement value is lower than the threshold. To do. As for the threshold value, in the case of illuminance, 1000 lux is set as the threshold value. However, in the case of a photosynthetic effective photon flux density having photosynthesis sensitivity, 20 μmol · m ⁻² S ⁻¹ is used, and in the case of irradiance, 4.0 Wm ^{− 2} is a threshold value. The photosynthetic photon flux density indicates the number of light quanta incident per unit time and unit area at a wavelength in the absorption wavelength region of chlorophyll.

  The plants targeted by the lighting device 10 are all crops that are generally cultivated by farmers. Specifically, fruit vegetables such as tomato, eggplant, cucumber, shiitake, green pepper, melon, watermelon, strawberry, lettuce, cabbage, Chinese cabbage, chingensai, spinach, komatsuna, perilla, etc., burdock, radish, carrot, etc. Root vegetables, soybeans such as soybeans, green beans, broad beans, peas, flowers such as chrysanthemum, roses, eustoma, carnations, and peanuts, and rice and tea.

  Each plant may be any of outdoor cultivation, greenhouse cultivation, and glass greenhouse cultivation. As for the shape of the culture medium for cultivation, even if it is shaped like a cocoon that is often found in open-field fields, soil is placed on a cultivation bench made of metal or wood, and a cocoon is formed there. Alternatively, a pot or a planter may be placed on the cultivation bench.

Specific implementation conditions for ultraviolet irradiation will be described. The artificial light source 11 is installed above or on the side of the target plant, and the plant is irradiated with light at a predetermined ultraviolet intensity. The ultraviolet intensity is 50 μW / cm ² or less. This is because, when ultraviolet radiation with a light intensity exceeding this level is used, the risk of causing burnt symptoms in the plant is extremely increased. In the verification test of the present invention, an artificial greenhouse 20 of a general agricultural greenhouse is used, and an artificial parallel to the beam 21 is provided below the beam 21 at a height of about 2 m from the surface of the agricultural greenhouse 20. As the light source 11, a fluorescent lamp type 20W appliance was installed. The ultraviolet intensity at the canopy surface of the plants on the straw 22 and the cultivation bench was about 10 kJm- ² per day.

  On the other hand, the ambient light sensor 13 (external light sensor) was installed in the vicinity of the plant planted in the greenhouse 20 for agriculture, and the real-time illuminance value in the vicinity of the plant growth point was measured. In the verification test, when the illuminance value from the external light sensor 13 is less than about 1000 lux, the test section suppresses the 280-340 nm ultraviolet radiation from the artificial light source 11 and the ultraviolet radiation even if the illuminance value is less than about 1000 lux. A control plot was set up that would not hold down. The plant was a strawberry.

  The photograph which image | photographed the strawberry leaf in a demonstration test is shown in FIG.2 and FIG.3. FIG. 2 is a photograph of a strawberry leaf cultivated in the test area, showing healthy leaves without leaf burn symptoms. FIG. 3 is a photograph of a strawberry leaf cultivated in the control group, in which a part of the leaf is discolored and leaves with larger irregularities appearing on the surface than normal. That is, the leaves of strawberries cultivated in the control group showed leaf burning (formation of anthocyanin having a red pigment on the surface of the leaves) due to ultraviolet radiation of 280 to 340 nm, and no leaf burning was observed in the test group. Table 1 summarizes the test results. It was confirmed that the plant disease control effect by turning on the artificial light source 11 and the prevention of leaf burn by turning off the artificial light source 11 were confirmed.

  As described above, when the illuminance is approximately 1000 lux or less where the resistance of the plant to the ultraviolet rays is reduced, the lighting device 10 can turn off the artificial light source 11 and does not irradiate the ultraviolet rays. .

  Here, the principle of plant disease control by ultraviolet irradiation will be described. By irradiating plants with UV-B, disease control is performed based on the following two principles.

  One of the principles of plant disease control is to make plants difficult to get sick. Normally, when a plant is infected with a disease-causing bacterium, an induced resistance expression against a pathogenic bacterium, a so-called plant immune system, is activated as a defense reaction against the disease. In this system, when a part of the tissue of a plant is subjected to external factors (stress) such as infection by pathogenic bacteria, a signal substance is released from the infected site, and it is still infected through the plant body. It reaches a non-existing site and induces the expression of genes involved in resistance expression there. Substances involved in this resistance include PR-proteins (Pathogensisi-Related Proteins), which are enzymes that dissolve the cell walls of pathogenic bacteria and have resistance activities such as glucanase and chitinase, and phytoalexins that are toxic to pathogenic bacteria (antibacterial activity) Substances and food repellent active substances). In the case of the present invention, as an external factor (stress), a plant is irradiated with ultraviolet rays containing UV-B as a light stimulus to induce expression of a gene involved in disease resistance.

Another principle of plant disease control is to prevent the disease from spreading by acting directly on the filamentous fungus that is the basis of the plant disease to suppress the growth of the mycelium. The filamentous fungi are, for example, powdery mildew fungus, gray fungus fungus, anthracnose fungus, downy mildew fungus, Suscabie fungus and the like. Patent Document 1, the ultraviolet UV-B intensity 60μW / cm ² or less (preferably 50 W / cm ² or less in consideration of leaf scorch for young seedlings and high light sensitive plants) irradiating the plant It is described that the generation of mold is suppressed. Further, in subsequent laboratory experiments by the present inventor, irradiation of 5 to 50 μW / cm ² of UV-B to the gray mold or anthracnose fungi inoculated on the agar medium can suppress the subsequent growth of mycelia. (There is no change in the size of the colonies of bacteria even if they are cultured for 1 week in a thermostatic chamber).

  When the illuminance measured by the external light sensor 13 is approximately 1000 lux or less, the control unit 12 of the present lighting device 10 controls the auxiliary light source 14 so that the illuminance on the plant is approximately 1000 lux or more.

  The external light sensor 13 is installed at the same height as the growth point near the plant crown surface in the vicinity of the plant, and measures the illuminance value received by the plant from the sun or the auxiliary light source 14 in real time. In the initial state, the auxiliary light source 14 is turned off, and the illuminance by sunlight is measured by the external light sensor 13. When the illuminance measured by the external light sensor 13 is about 1000 lux or less, which is a threshold value, the auxiliary light source 14 is controlled to be turned on so that the illuminance on the plant is about 1000 lux or more. Since the illuminance measured by the external light sensor 13 by the auxiliary light source 14 is approximately 1000 lux or more, the artificial light source 11 that emits ultraviolet light is not turned off.

  In this way, even if the illuminance due to sunlight, that is, external light is reduced to about 1000 lux or less, the auxiliary light source 14 is controlled to be turned on so that the illuminance on the plant is about 1000 lux or more. Can be ensured and the irradiation schedule of ultraviolet rays can be observed, and therefore the efficiency of plant disease control can be improved.

In addition, when the integrated light amount of the external light of the previous day measured by the external light sensor 13 is 12000 lux · hour or less, the control unit 12 has the integrated UV-B irradiation amount measured by the ultraviolet intensity meter 15 of 0 on the day. The lighting control of the artificial light source 11 is performed so that it becomes ² kJm ⁻² day ⁻¹ or more and 8 kJm ⁻² day ⁻¹ or less.

  The operation procedure of the illumination device 10 will be described below.

Procedure 1: The artificial light source 11 for emitting ultraviolet rays is installed on the upper part or the side part of the plant body. Ultraviolet radiation by the artificial light source 11 is set so that the ultraviolet intensity (UV-B) of the plant grass crown surface is 50 μW / cm ² or less.

  Procedure 2: Next, according to the kind and state of a plant, the external light sensor 13 and the ultraviolet intensity meter 15 are installed in the vicinity of the target plant in the cultivation site. The external light sensor 13 and the ultraviolet intensity meter 15 are connected to the auxiliary light source 14 and the artificial light source 11 directly or indirectly via the control unit 12.

Procedure 3: When starting cultivation, for example, the artificial light source 11 is controlled to be turned on by the control unit 12 so that the accumulated ultraviolet intensity per day is 10 kJm ⁻² day ⁻¹ or less, and the irradiation time per day is defined. . In addition, referring to the integrated irradiation amount of external light on the previous day, lighting control is performed so that it is 8 kJm ⁻² day ⁻¹ or less when it is approximately 12000 lux · hour or less.

  Procedure 4: During irradiation of the artificial light source 11 during the day, the outside light sensor 13 continuously measures the light intensity (either illuminance, photosynthetic effective photon flux density, or irradiance) in the vicinity of the plant in real time. The measurement value signal is sent to 12.

  Procedure 5: The control unit 12 always determines whether the transmitted light intensity is higher or lower than the threshold value of the lighting device 10.

  Procedure 6: When the result determined by the control unit 12 is lower than a preset threshold value, a signal for quickly turning off the artificial light source 11 is transmitted to the artificial light source 11.

  Procedure 7: When artificial light source 11 receives a signal to turn off from control unit 12, artificial light source 11 is turned off immediately.

  Procedure 8: After a while, when the measured value of the light intensity sent from the outside light sensor 13 rises and exceeds the threshold value, the control unit 12 artificially sends a control signal for quickly turning on the artificial light source 11 again. Transmit to the light source 11.

  Procedure 9: When the artificial light source 11 receives a control signal to be turned on from the control unit 12, the artificial light source 11 is immediately turned on again.

  Procedure 10: The control unit 12 has a timer function, and repeats the procedure 4 to the procedure 9 as many times as possible during the one-day light irradiation time specified by the timer.

  Step 11: After the timer is turned off, even if the illuminance measured by the external light sensor 13 exceeds the threshold value, the artificial light source 11 is not turned on until the timer is turned on next time.

Next, verification conditions and results of the lighting device 10 will be described. As a verification condition, the ultraviolet irradiation amount in the test group is set to three conditions of 3, 6, 10 kJm ⁻² day ⁻¹ , and no ultraviolet light is irradiated in the control group. The cultivation period was 3 weeks, and the number of strains examined was 4 in each ward.

The results are shown in Table 2. When diseased leaf rate = number of diseased leaves / total number of leaves × 100%, the diseased leaf rate was as high as 75.0% when UV irradiation was not performed, but when the UV irradiation amount was 3 kJm ⁻² day ⁻¹ , the diseased leaf When the rate was as low as 2.0% and the UV irradiation amount was 6 kJm ⁻² day ⁻¹ , the diseased leaf rate was 0.0%.

Regarding the relationship between the accumulated amount of external light on the previous day and leaf burning, on the next day after the extreme cloudy weather, when the UV irradiation amount was 10 kJm ⁻² day ⁻¹ , leaf burning was observed and 6 kJm ⁻² day ^{− In} the case of ¹ , it was confirmed that leaf burning was not possible. Therefore, when the integrated light amount of the external light of the previous day measured by the external light sensor 13 is approximately 12000 lux · hour or less, the maximum value of the integrated UV-B irradiation amount measured by the ultraviolet intensity meter 15 is 8 kJm ^{− It} was set to ² day ^-1 . As for the lowest value, 0.2 kJm ⁻² day ⁻¹ was obtained because the disease control effect was confirmed even in a short irradiation of less than 3 hours / day while irradiating light with a weak ultraviolet intensity of 5 μW / cm ² in other experiments. did.

  In this way, the day after the extreme cloudy weather that continues to rain all day, the resistance of the plant to ultraviolet rays (UV-B) is weakened, and leaf burn symptoms are likely to occur. Since the light source 11 is turned on to control the UV-B integrated irradiation amount, the plant disease control effect can be maintained while preventing the leaf burn of the plant.

  In the present lighting device 10, the auxiliary light source 14 may be omitted in consideration of cost effectiveness in the installation environment. In this case, since the irradiation schedule of ultraviolet rays cannot be observed, the efficiency of plant disease control is lowered, but the cost of the apparatus can be reduced. Further, the ultraviolet intensity meter 15 may be omitted. In this case, on the next day when the cloudy weather continued, leaf burn symptoms are likely to occur, but the cost of the apparatus can be reduced.

  The present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made without departing from the scope of the invention. The wavelength range of the ultraviolet radiation of the artificial light source 11 may be 280 to 315 nm out of 280 to 340 nm.

The external view of the illuminating device for plant disease control which concerns on one Embodiment of this invention. A photograph of the leaves of strawberries grown in the test area in the verification test of the device. A photograph taken of the leaves of a strawberry grown in a control plot in the same test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illumination device 11 for plant disease control Artificial light source 12 Control part 13 Ambient light sensor 14 Auxiliary light source 15 Ultraviolet intensity meter

Claims (3)

Plant disease control comprising: an artificial light source that emits ultraviolet light in the wavelength range of 280 to 340 nm as a main wavelength; a control unit that controls lighting of the artificial light source; and an external light sensor that measures light intensity in the wavelength range of 380 to 780 nm Lighting equipment for
The plant disease control lighting device, wherein the controller turns off the artificial light source when the illuminance measured by the external light sensor is approximately 1000 lux or less. An auxiliary light source for irradiating light in a wavelength range of 400 to 700 nm;
The said control part controls lighting of the said auxiliary light source so that the illumination intensity on a plant may be about 1000 lux or more, when the illumination intensity measured by the said external light sensor is about 1000 lux or less. A lighting device for controlling plant diseases according to 1. An ultraviolet intensity meter for measuring ultraviolet radiation in the 280 to 315 nm wavelength region (UV-B);
When the integrated light amount of the external light of the previous day measured by the external light sensor is approximately 12000 lux · hour or less, the control unit determines that the integrated UV-B irradiation amount measured by the ultraviolet intensity meter is 0.00. The lighting device for controlling plant diseases according to claim 1, wherein the artificial light source is controlled so as to be ² kJm ⁻² day ⁻¹ or more and 8 kJm ⁻² day ⁻¹ or less.