JP6061124B2 - How to control powdery mildew occurrence - Google Patents

Description

  The present invention relates to a powdery mildew control technique for fruits and vegetables, and particularly to a fruit and vegetable cultivation method (agricultural crop cultivation method) for controlling powdery mildew by irradiation with near infrared light.

  Although there are various plant diseases, 80% of them are caused by mold, and chemical control by using agricultural chemicals (bactericides) is common as a control method. However, when pesticides are used, resistant bacteria appear, conventional pesticides do not work, and there is concern that the damage will spread.

  Vegetables and fruits are seriously damaged by powdery mildew, a type of mold, and infection has been confirmed in at least 10,000 types of plants. Various pesticides have been developed to control this, but in fact, resistant bacteria to sterol demethylase inhibitors and strobilurins have been reported.

  On the other hand, a control method by irradiation with high energy ultraviolet light is also being studied. However, ultraviolet rays may affect the human body such as eyes and skin, and there is a problem in that it imposes a burden on producers depending on the irradiation conditions.

JP 2009-261311 JP2009-153397 JP2009-022175 JP 2005-328734 A

Arase, Satoshi Ueno, Junichi Kihara: Induction of disease resistance by red light irradiation and its application to disease control Plant protection: 64 15-18 (2010). Rahman, MZ., Kanam, H., Ueno, M., Kihara, J., Honda, Y. and Arase, S. Suppression by red light irradiation of Corynespora leaf spot of cucumbercaused by Corynespora cassiicola. Journal of phytopathology158,378- 381 (2010).

The present invention was made in view of the above, and an object thereof is to provide a novel way to control powdery mildew.

The method for suppressing powdery mildew occurrence according to claim 1 is characterized in that a near-infrared light is continuously irradiated to a crop all day .

The method for suppressing powdery mildew according to claim 2 is characterized in that, in the method for suppressing powdery mildew occurrence according to claim 1, near infrared light having a center wavelength of 740 nm is used.

The method for suppressing powdery mildew according to claim 3 is the method for suppressing powdery mildew occurrence according to claim 1 or 2, wherein the irradiation is continuously performed at a radiation intensity of at least 59 μW / cm ² per crop surface for one week . It is characterized by.

Incidentally, near-infrared light from the viewpoint of power consumption, it is preferable to use an LED light source or HEFL source.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the crop cultivation method suitably employable for a plant factory, without using an agrochemical.

It is the figure which showed the spectrum of the red HEFL light source. It is the photograph which showed the result of inoculating powdery mildew spore in the cucumber leaf and irradiating with red light. It is the figure which showed the spectrum of the white HEFL light source. It is the figure which showed the spectrum of the blue HEFL light source. It is the figure which showed the spectrum of the near-infrared-light HEFL light source. It is the photograph which showed the result of inoculating powdery mildew spores on the cucumber leaf and irradiating with white light, blue light and near infrared light. In addition, the result of irradiation with red light is also shown. It is the photograph which showed the result of having compared the inhibitory effect of the cucumber powdery mildew by the difference in the irradiation intensity of near infrared light. It is the photograph which showed the result of having compared the inhibitory effect of the cucumber powdery mildew by the difference in the irradiation time of near infrared light. It is the photograph which showed the result which compared the suppression effect by the difference in the irradiation light regarding another powdery mildew.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the above-mentioned Non-Patent Documents 1 and 2, the inventors of the present invention irradiate rice blast, cucumber brown spot, eggplant blight, etc. with red light (600 nm to 700 nm, center wavelength 650 nm), thereby causing the disease. Clarified that it can be suppressed.

  Next, based on this finding, cucumber leaves inoculated with cucumber powdery mildew spores were irradiated with red light (wavelength 610 nm) to examine whether or not they had a controlling action.

Specifically, cucumber leaves were grown to 2-3 leaves, and cucumber powdery mildew spores were adjusted to 1 × 10 ⁵ spores / ml, and cucumber leaves were spray-inoculated using a sprayer.

  Next, a red HEFL light source (manufactured by Tsujiko Co., Ltd .: center: 610 nm: 10 W) was installed 15 cm above the leaf and lit continuously for 24 hours and observed for a week (this light source generated less heat and directly below light efficiently It has the feature of dropping into The spectrum of the light source is shown in FIG.

  The state of the cucumber leaf after one week is shown in FIG. As can be seen from FIG. 2, powdery mildew has developed on almost the entire surface, and it has been confirmed that red light has no effect on controlling cucumber powdery mildew.

  Next, the same test was conducted by changing the wavelength. Specifically, an experiment was performed using a white light source (wavelength 400 nm to 700 nm), a blue light source (center wavelength 450 nm), and a near-infrared light source (center wavelength 740 nm). The spectrum of the light source is shown in FIGS.

  The state of the cucumber leaf one week later is shown in FIG. As is clear from FIG. 6, although the white light as well as the expected blue light had no control effect at all, it was surprisingly confirmed that near infrared light has an excellent control effect. The disease severity was calculated using a commonly used calculation formula. That is, when the leaves are observed, there is no lesion: 0, 1-2 lesions on one leaf: 1, one leaf lesion is less than 1/4 per leaf area: 2, one leaf The lesions are classified into 1 / 4-1 / 2 per leaf area: 3 and 1 leaf lesion per half or more per leaf area: 4, {(1 × number of individuals with disease incidence 1 + 2 The disease incidence was calculated by applying the following equation: x number of individuals with disease incidence 2 + 3 x number of individuals with disease incidence 3 + 4 x number of individuals with disease incidence 4) / 4 x number of individuals studied.

Next, the suppression of cucumber powdery mildew caused by the difference in irradiation intensity of near-infrared light was examined. Cucumbers are grown to 2-3 leaves, sprayed with cucumber powdery mildew spores adjusted to 1 × 10 ⁵ spores / ml, and a near-infrared HEFL light source (manufactured by Tsujiko Co., Ltd .: center wavelength 740 nm) ) Was used to adjust the irradiation intensity by varying the distance from the leaves. Specifically, the irradiation intensity is 125 μW / cm ² (the light source is 5 cm away from the leaf), 77 μW / cm ² (the light source is 10 cm away from the leaf), 59 μW / cm ² (the light source is 15 cm away from the leaf). As separation, each was continuously irradiated for 24 hours × 1 week. In addition, the said intensity | strength is the measured value measured on the surface of the leaf.

As shown in the figure, it was confirmed that powdery mildew could be suppressed, and it was confirmed that the irradiation intensity was 59 μW / cm ² .

  Next, suppression of cucumber powdery mildew caused by differences in irradiation time was examined. The same experimental environment as the above experiment was prepared, and a near-infrared light source was irradiated every 12 hours, that is, after irradiation for 12 hours, left in a dark room without irradiation for 12 hours, and then irradiated to non-irradiated in a 12-hour cycle as well. The experiment was repeated weekly. The results are shown in FIG.

  As shown in the figure, it was confirmed that the effect of suppressing cucumber powdery mildew was low by intermittent irradiation for 12 hours.

From these results, it was confirmed that cucumber powdery mildew can be controlled by irradiation with infrared light, particularly near infrared light, although the effect is not obtained with red light. For irradiation, an intensity of 59 μW / cm ² or more is preferable, and continuous irradiation for 24 hours is preferable.

  Based on the above results, other powdery mildew diseases were also examined. FIG. 9 shows the light source of near-infrared light (center wavelength 740 nm) for the pumpkin powdery mildew spores sprayed on the pumpkin leaves and the melon powdery mildew spores sprayed on the melon leaves. It is the figure which showed the result of having irradiated white light continuously for 24 hours x 1 week. As shown in the figure, it was confirmed that any powdery mildew was not able to obtain a controlling effect with white light and obtained a controlling effect with near infrared light.

  Therefore, it was confirmed that powdery mildew can be widely controlled by irradiating a predetermined amount of near infrared light.

  According to this method, it is possible not only to reduce the environmental load such as the occurrence of resistant bacteria and the reduction in the amount of conventional fungicides, but also to increase the added value as the safety of crops. Actually, the powdery mildew control areas of strawberries and cucumbers in 2011 are described as 27558ha and 32810ha respectively, and the amount of pesticide used for general powdery mildew is considered to be 200 to 300 liters per 10a. When the method is applied to a target area of 10% including other fruits and vegetables, it is possible to reduce the amount of pesticide used by about 10 million liters.

Claims (3)

A method for suppressing powdery mildew disease characterized by continuously irradiating a crop with near infrared light all day . The method for suppressing the occurrence of powdery mildew according to claim 1, wherein near-infrared light having a center wavelength of 740 nm is used. The method for suppressing the occurrence of powdery mildew according to claim 1 or 2, wherein continuous irradiation is performed for at least 59 μW / cm ² or more for 1 week per crop surface.