JPS6132283B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for protecting agricultural crops by suppressing disease-causing bacteria in the soil and using a novel fertilization method that does not have an adverse effect on fertilizer-degrading microorganisms, in order to overcome problems caused by continuous cropping of agricultural crops. Continuous cropping disorder occurs when the same crop is continuously cultivated in the same soil, resulting in abnormal growth of pathogenic bacteria such as Fusarium, Pythium, Rhizoctonia, Rhizopus Phytophthora, and Phytophthora, resulting in an imbalance in the B/F value of the soil. It is generally known that this occurs when the . It is economically difficult to rotate crops on a small cultivated area like in Japan, especially with the current large-scale greenhouse horticulture with fixed cultivation and a distribution system based on intensive cultivation of a single crop. It has to be a series of works. Conventionally, soil disinfection has been generally used as a method to solve this problem. Examples include irrigation with poisonous gas pesticides and thermal disinfection using steam. These methods are effective temporarily, but because they destroy all soil microorganisms and disrupt the balance of B/F values in the soil, when we look at the outbreak of pathogenic bacteria, they rapidly disappear because there are no microorganisms that can compete with them. It multiplies and causes great damage to crops. The present invention aims to reduce the enormous cost required for conventional soil disinfection and improve the B/F value by adding non-toxic cinnamaldehyde or a low-toxic cinnamaldehyde derivative to fertilizer. This relates to a new method of fertilization that maintains balance. Fertilizers can be broadly divided into soil fertilizers that are absorbed through the roots;
There is a liquid fertilizer that is absorbed through the leaves. The present invention can be applied to either of these two different fertilization methods. For example, when adding cinnamaldehyde or a halogen derivative to soil fertilizer, add 200 ppm of cinnamaldehyde or its derivatives to the total amount of the base fertilizer prepared by adsorbing porous viscosity material into dry powder or granules and the added viscosity material. All you have to do is impregnate it. When adding it to liquid fertilizer, it is best to use a diluent that is compatible with the liquid fertilizer and disperse it evenly to a maximum of 200 ppm based on the total amount of base fertilizer and diluent.
If you want the liquid fertilizer to be transparent and the additives to be transparent, use non-toxic substances such as ethyl acetate, alcohol, sugar ester, propylene glycol, polypropylene glycol, ethylene glycol, or low-toxic diluents. All you have to do is choose. Cinnamaldehyde has the general formula The halogen derivative is represented by the general formula It is expressed as (In the formula, R ₁ is hydrogen, nitro group, chlorine, or dimethylamino group, R ₂ is methyl group or hydrogen, and X is bromine or chlorine.) The antibacterial effects of cinnamaldehyde and halogen derivatives are as follows. The test method and test bacteria were Fusarium fungi, White silk fungus, Phytophthora blight of eggplant, Rhizoctonia fungi, and Pythium fungi. First, the cinnamaldehyde stock solution was diluted 100 times, that is, 1 ml of the stock solution was added to 100 ml of water, and then ground and stirred with a Polytron homogenizer to give 25, 50, 100,
Add it to 100 ml of PAS medium to give a concentration of 200 ppm and dispense it into a 9 cm Shearley as usual to create a flat medium. Each of the above bacteria, which had been cultured on a flat surface in the center of the medium, was cut into 5 mm squares and placed on the bed. The bacteria were cultured at 25°C, and the growth diameter of the bacteria was measured after a predetermined day to determine the effectiveness of the drug. As a result Fusarium
For oxysporum fsp. cucumerinum (a fungus that causes cucumber vine splitting), the inhibitory effect on mycelium growth was seen compared to the control without additives, but the inhibiting power was weak between 25 and 200 ppm and up to 100 ppm. However, at 200 ppm, no growth was observed and a remarkable inhibitory effect was exhibited. The inhibitory effect on the white silk disease fungus was observed in the range of 25 to 200 ppm, but the inhibitory effect was weak up to 100 ppm, and at 200 ppm, it showed a remarkable effect and no growth was observed at all. phytophthora cp isolated from eggplant leaves
The growth inhibiting effect was observed in the range of 25 to 200 ppm, and in particular, at 100 ppm and 200 ppm, no growth was observed at all, showing a remarkable effect. The growth inhibiting effect on Rhizoctonia solani type A seedling blight was observed in the range of 25 to 200 ppm, and in particular, no mycelial growth was observed at 50, 100, and 200 ppm, which had a remarkable effect. Pythium spp seedling gall disease
Effects are seen in the range of 25 to 200 ppm,
Mycelial growth was completely inhibited, and there was a remarkable effect. What is most noteworthy about the present invention is that, as mentioned above, soil pathogens are suppressed, but beneficial bacteria are not affected at all. Soil microorganisms are highly diverse and have complex aspects such as biological control between microorganisms, symbiotic action between actinomycetes and bacteria, and dynergistic action. To avoid efficacy testing, we used recently commercially available commensal bacteria (SNKD bacteria) as the test material. SNKD bacteria is yeast 4
Species (Saccaromyces, Candida,
Endomycopris, Cladosporium) 2 types of Actinobacteria (Nocardia, Streptomyces) 6 types of Bacillus.
Clostridium, Aolomonas, Pseudomonas,
Bacterium, Rhizobium, useful filamentous fungi
It is a complex of Basidomycetes. These SNKD bacteria are said to have chitinase activity that decomposes filamentous fungi, and are said to reduce soil-borne pathogens, but their effectiveness is weak. Therefore, although it suppresses pathogenic bacteria in the soil to some extent, it loses its suppressive power when it multiplies in large quantities. As a test method, cinnamaldehyde 200ppm,
Fusarium bacteria in Rose bengal agar medium containing 2000ppm, SNDK bacteria in Peptone yeastestract
All were mixed appropriately in agar medium and cultured at 28°C for 3 days. The SNKD bacteria continued to grow for another 2 days, and the results observed after 5 days are as follows.

[Table] At 2000ppm, the total bacterial counts of both Fusarium and SNKD bacteria decreased to less than 1% of the control, and yeasts were hardly seen, but at 200ppm, yeasts decreased, but other microorganisms were hardly affected. . The results of an experiment to see how the fertilizer mixed with cinnamaldehyde affects crops are as follows, and clearly showed that the B/F value was in better condition than in the control plot. The roots of all crops are strong and the ability to break down and absorb fertilizers is good.

【table】

[Table] Next, we will discuss the inhibitory effect on filamentous fungi by applying mixed fertilizer with liquid fertilizer. Commercially available liquid fertilizer (product name)
I used Deka Ace. This liquid fertilizer is registered as a liquid trace element compound fertilizer that contains trace elements such as boron and manganese, as well as rutin. This liquid fertilizer is usually diluted 1000 times and sprayed on the leaves.
Add cinnamaldehyde to propylene glycol and sugar ester, dilute 1000 times, weigh so that the cinnamaldehyde content is 200ppm, add an equal amount of 100 to 100 Decaace, stir to mix uniformly, and convert to 10A. 150 (1000x solution) was sprayed. The results are as follows. Cultivation requirements for test materials Prince melon grown in a house was used. March 1981
The soil was sterilized in a 15cm x 30cm x 15cm polyethylene plantain in mid-month, sown on April 2nd, and grafted onto pumpkin rootstock on April 20th. Planting took place on April 25th. The planting interval was 250 cm x 75 cm, equivalent to 500 plants per 10 are. Each plant had 3 main branches, and each 3 main branches bore fruit, resulting in 9 fruits per plant. Two target plots and two test plots were established, each containing 20 plants. The spraying timing, concentration, and amount of pesticides used are as follows.

[Table] The disease incidence was investigated on August 7th. 1 per share
Main branches of books were randomly selected and the area of powdery mildew that had grown on them was visually judged in 6 grades.

[Table] Fruits were harvested 33 to 36 days after flowering, and were sorted into four grades based on appearance: excellent, excellent, good, and poor, the ratio was calculated, and fruit weight and sugar content were measured using a refractometer. . The disease incidence rate in the target area was 2.2 (damage area rate 44).
%), the test plot had an index of 0.3 and a damage area rate of 6%, which was a significant difference. Regarding fruit quality, the target plots had more disease damage than the test plots, the appearance was significantly inferior due to exposure to direct sunlight, the proportion of excellent fruits was low, and the proportion of inferior fruits was high. The sugar content was not much different between the target plot and the test plot, and was slightly higher in the test plot.

[Table] Next, we will discuss how to protect crop rhizospheres by applying brominated cinnamaldehyde to fertilizer.
The manufacturing method has already been described in Japanese Patent Publication No. 45-39905, so it will be omitted here, and the sustained effect when it is added to fertilizer and applied will be explained. The differences between cinnamaldehyde alone and cinnamaldehyde bromide are as follows. The former is non-toxic and has little residual effect at 20℃±2℃.
The evaporation rate at room temperature is 0.0007 mg cm ² /hr. The latter is toxic and has residual effects. The evaporation rate under the same conditions as the former is 0.00004 mg. The toxicity is quite high, with a mouse oral LD ₅₀ of 1.000 mg/Kg. However, it is quite low compared to soil disinfection currently commonly used. That is, the mouse oral LD ₅₀ of the D-D drug was 300 mg/Kg, and the EDB drug was 420 mg/Kg.
Kg chloropicrin is highly toxic at 20ppm when inhaled by humans. Brominated cinnamaldehyde was dissolved in a low-toxicity organic solvent such as ethyl acetate, adsorbed onto dry fine powder of porous viscous atomite, and weighed to give a total concentration of 200 ppm. It was mixed in and fertilized tomatoes. The results are as follows, and it was clear that the effect was longer lasting than that of the cinnamaldehyde group, and there was a noticeable difference in the later harvest period than in the early harvest period. The target disease was tomato late blight, and the experimental fertilization area was 100 kg of young soil lime, 100 kg of CDU chemical fertilizer, and oil cake.
100Kg, compost 1000Kg/10a, and in addition to the above, test A area was CDU chemical + 200 ppm cinnamaldehyde, and test B area was CDU chemical + 200 ppm brominated cinnamaldehyde. June 4, 11, 16, 24, July 1, 1981
A total of 9 times on Sunday, 7th, 12th, 20th, and 28th, use a power sprayer to spray 600x Mannebudaisen liquid at 10 are conversion rate.
was scattered. On June 25th and July 5th, the presence or absence of late blight was determined for each leaflet of all the leaves of the four plants in one district, and the diseased leaf rate for compound leaves and the diseased leaflet rate for each leaflet were determined. See you on July 30th
On the same day, all fruits of the first and second tiers of 10 plants in one district were examined for the presence or absence of disease.

[Table] Harvest is from 7/20th to 7/28th for the first stage to 3rd stage fruits, and for the latter half from 8/5th to 8/25th from 3rd stage to 5th stage.
I harvested the tiered fruit. All test plots showed a tendency to increase yields compared to the target plots, and in particular, plot B (bromine cinnamaldehyde plot) was clearly superior in number and average fruit weight to plot A, and the absorption of rhizosphere fertilizer in the soil was better. ,
It was proved that the B/F value remained in a good condition.
In particular, the numbers in the latter half revealed that the lasting effects were better than in Ward A.

[Table] Open-field tomatoes in summer and autumn have noticeable fruit cracks, but compared to the target plot, the test plot has fewer disease outbreaks, higher yields, and a lower fruit split rate. As described above, the present invention suppresses soil pathogens by adding non-toxic cinnamaldehyde or low-toxic cinnamaldehyde derivatives to fertilizer, but has no effect on useful bacteria. It is possible to overcome the problem of continuous cropping of agricultural products. In addition, although cinnamaldehyde derivatives are toxic, they are considerably less toxic than soil disinfectants currently in common use.
It has a better residual effect than when cinnamaldehyde is used, and has a sustained effect, making a noticeable difference in the later stages of harvest than in the early stages. As described above, the present invention can eliminate problems caused by continuous cropping of agricultural products by adding cinnamaldehyde or cinnamaldehyde derivatives to fertilizer and applying the fertilizer, thereby reducing the huge cost required for conventional soil disinfection. .

Claims (1)

[Claims] 1. A method for protecting agricultural crops, which comprises adding cinnamaldehyde or a cinnamaldehyde derivative to fertilizer and applying the fertilizer.