JPH07187914A - Agent for controlling red rot of cultured laver - Google Patents

Abstract

PURPOSE:To obtain an agent for controlling red rot of cultured laver and capable of exterminating red rot pathogen in a short time even at a low temperature without damaging the laver by using itaconic acid in combination with at least one kind of compound selected from hydrochloric acid, phosphoric acid, acetic acid, phytic acid and succinic acid. CONSTITUTION:Pathogen of red rot is exterminated in a short time (<=60sec) by using an aqueous solution of itaconic acid having a concentration of <=0.5w/v% in combination with at least one kind of compound selected from hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid and succinic acid. This agent can remarkably shorten the work time to enable the extermination with an under-net boat and prevent the total destroy of laver by red rot. This extermination agent exhibits excellent effect by the use of one or more acids requiring long extermination period together with itaconic acid which has high fungicidal potency and poor solubility in seawater and is difficult to keep high concentration in water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red rot fungicide for seaweed aquaculture. In particular, the present invention relates to a disinfectant capable of exterminating red rot bacteria in an extremely short time and not harming the main body of seaweed, such as sterilization treatment by a moguri ship.

[0002]

2. Description of the Related Art In the cultivation of seaweed, when red-rot fungi are generated, the quality of seaweed is deteriorated, and when the seaweed becomes severe, there is a risk of production being completely lost. Generally, in seaweed aquaculture, a draining operation is performed as a method for preventing and controlling disease. This is a method of removing the seaweed net from the seawater once and drying it, but this method is not very effective in taking a lot of labor and time.

As another method, there is a method of eradicating the red rot fungus by immersion treatment in an organic acid solution such as citric acid or malic acid. With a 1-2% solution of citric acid, 5
Processing for 10 minutes is performed. These have the drawback that it takes too long to control the red-rot fungus.

[0004] A disease called red rot disease occurs rapidly when the seaweed fronds grow and finally harvest is possible, and it spreads to all the fishing grounds within a few days, causing the fronds to die and flow out. The damage is large because it ends up.

Regarding the control of red rot fungi, the following patents have been disclosed. Japanese Examined Japanese Patent Sho 60-13647
Japanese Patent Laid-Open Publication No. 2003-242242 contains citric acid in an amount of 0.3 to 5.0% by weight, p
A seaweed aquaculture method is described in which weeds are immersed in a treatment solution having H of 1.0 to 6.0, and extermination and prevention of diseases are performed.

Japanese Patent Publication No. 60-13648 discloses a method in which an inorganic acid such as hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid is added to adjust pH.
A seaweed aquaculture method by controlling and preventing weeds and diseases by adjusting the algae to 1.0 to 4.0 is described.

[0007] Japanese Patent Publication No. 60-21950 discloses a fertilizer for seaweed cultivation containing phytic acid or a salt thereof as an active ingredient, a preventive effect against red rot disease, and a diatom exterminating effect.

In Japanese Patent Laid-Open No. 57-8722, a net under nori culture is treated with a treatment solution containing phosphoric acid or a salt thereof,
A seaweed cultivation method for removing and preventing diseases such as algae and red rot is disclosed.

[0009] Since red rot fungi have a high infectivity when they are generated, they must be quickly treated to completely kill them.
Even if 99% of the red-rot fungi in the seaweed leaves were killed, the remaining 1% of the red-rot fungi would propagate rapidly, and the leaves would turn red the next day. I will end up. Therefore, 100% must be removed. Even if it can be completely exterminated, infection from the sea will occur immediately,
If it is not treated every 2 to 6 days, the seaweed will be destroyed.

Nori producers average 100 to 200
Since nori seaweed nets are collected and the current treatment agent requires a treatment time of 5 minutes or more per one net, considering the time before and after, the treatment can be done in about 8 hours which can be done in one day. The number of nets that can be formed is 30 to 40. Therefore, as the spread of red rot becomes worse, the elimination of red rot bacteria will not be in time,
The current situation is that the seaweed is rotten and no production is produced, so the seaweed production ends.

Further, in order to shorten the working time, a ship called a moguri ship is used in which the ship is dipped under the nori net to pass the net through a solution such as fertilizer or citric acid. . Due to the performance of the ship, this can be immersed for a very short time of 20 to 50 seconds. Therefore, there is a strong demand for the development of a powerful treating agent for combating red-rot fungi.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a drug capable of controlling red rot fungi in a short time without damaging the seaweed itself.

[0013]

[Means for Solving the Problems] As a result of earnest research on the development of a drug capable of controlling red rot bacteria in a short time, the present inventors have found that itaconic acid, hydrochloric acid, acetic acid, lactic acid, phytic acid, succinic acid An exterminating agent containing at least one selected from the group consisting of:
They have found that they can be removed in an extremely short time, and have completed the present invention.

That is, in the present invention, at least one selected from the group consisting of hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid and succinic acid is mixed with an aqueous solution of itaconic acid of 0.5% by weight / volume or less. It is a red-rot fungicide for cultured seaweed.

As can be seen from Test Example 1, the present inventors have found that, among the acidic substances, itaconic acid has a very high bactericidal activity against red-rot fungi, and further investigated to enhance the bactericidal activity. As a result, as shown in Test Examples 4 to 8,
When itaconic acid is used in combination with one of citric acid, malic acid, tartaric acid, gluconic acid and ketoglutaric acid, the eradication time of red-rot fungus is equal to or longer than that of itaconic acid alone. And there is no combined effect. However, when itaconic acid is used in combination with at least one selected from the group consisting of hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid and succinic acid, the red rot fungus is treated in a shorter time than itaconic acid alone. I was able to get rid of it with.

In particular, in order to disinfect the red-rot fungi by treating with the above-mentioned mogul, the red-rot fungi must be eliminated in 20 to 60 seconds. Test Example 2
More specifically, when itaconic acid is used alone, it must be treated at a concentration of 0.5% by weight / volume or more.

Itaconic acid has a low solubility in water, and it dissolves only 8.3% by weight / volume at 20 ° C. in water. Solubility is even smaller with seawater. Itaconic acid dissolves in seawater at 20 ° C. only up to about 2.5%. As shown by the solubility test of itaconic acid in Test Example 3, it takes time to dissolve it at 1.0% by weight / volume% or more and workability is poor. In case of Meguri boat, about 100
Since 0 liter of processing liquid is prepared, it is desired to have good solubility and workability.

Therefore, considering the solubility of itaconic acid, it is preferably used at 0.5% by weight / volume or less. Therefore, the present inventors have a synergistic effect in combination with the above-mentioned itaconic acid, that is, consisting of hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid and succinic acid, which can be eliminated in a shorter time than the case of itaconic acid alone. Using at least one selected from the group together, using itaconic acid at 0.5% by weight or less,
Moreover, it was possible to confirm this as a result of the test by paying attention to whether the red rot fungus could be exterminated by the treatment within 60 seconds.

Test Example 1 Itaconic acid, citric acid, malic acid, gluconic acid, tartaric acid, 90% acetic acid, 90% lactic acid,
Prepare a 0.5 wt / vol% seawater solution of succinic acid, 50% phytic acid and 36% hydrochloric acid, and treat the seaweed leaves infected with red rot fungus for 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds. Seconds, 1
Minutes, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes
After 10 minutes of immersion treatment, it was taken out, washed with seawater, and statically cultivated, and after 2 days, the state was observed under a microscope to examine the time for which red rot bacteria could be exterminated. Treatment water temperature is 20 ℃
I went there. The results are shown in Table 1.

[0020]

[Table 1]

(Test Example 2) In order to examine the relationship between the concentration of itaconic acid and the control time of red rot fungus, itaconic acid of 0.0
1, 0.05, 0.1, 0.2, 0.3, 0.5, 1.
A sea water solution of 0,1.5% by weight / volume was prepared and Test Example 1
Similarly to the above, a red rot control test was performed. Treated water temperature is 2
It is 0 ° C. The results are shown in Table 2.

[0022]

[Table 2]

In order to investigate the relationship between the concentration of itaconic acid, the dissolution time in seawater, and the temperature, 500 ml of seawater was added with itaconic acid to each concentration, and a test stirrer (LA) was added.
BO-STIRRR: LR-51B) 100 rpm
The time for dissolution was investigated by stirring at. The results are shown in Table 3.

[0024]

[Table 3]

[0025]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The concentration of itaconic acid is fixed at 0.5% by weight / volume, and hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid, and succinic acid are individually adjusted between 0.1-0.3% by weight / volume. The seaweed thalli infected with red rot fungus was immersed in seawater prepared by changing it to 5, 10, 20, 30, 40, 50 seconds, then taken out, washed with seawater, and statically cultivated for 2 days. The condition was inspected under a microscope to investigate the effect of controlling red rot fungus. The treated water temperature is 20 ° C.

The results are shown in Table 4 together with comparative examples. Judgment of the extermination effect of red rot fungus is based on the following criteria. ○: Completely eradicated △: Sufficiently suppressed, slight red-rot fungi are seen. ×: Red rot fungus has spread considerably.

[0028]

[Table 4]

When itaconic acid is 0.5% by weight / volume,
The present invention is a comparative example, but 0.5% by weight / volume%
If the concentration is increased up to 30 seconds, it can be removed in a processing time of 30 seconds.
In this case, if hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid, and succinic acid are used together in an amount of 0.1 to 0.3% by weight,
A treatment time of 20 seconds, and depending on the acid and concentration, a treatment time of 10 seconds can also be used for extermination.

As a comparative example, in the case where citric acid, malic acid, tartaric acid, gluconic acid, and ketoglutaric acid were used in combination with itaconic acid, the concentration of itaconic acid was fixed at 0.5% by weight / volume, and other acids were respectively added. 0.1 to 0.3 weight / individual
The effect of controlling the red rot fungus was investigated in the same manner as in Examples 1 to 18 for the seawater solution prepared by changing the amount between the volume%.
The same criteria apply to the extermination effect. The results are shown in Table 5.

[0031]

[Table 5]

When these acids are used together, with the exception of a few, there is no synergistic effect when other acids are used together, and in some cases the treatment time is rather long, It turned out that the effect was inferior. Therefore,
Obviously, it is not necessary to use other acids together.

In the above examples, the concentration of itaconic acid was increased to 0.5% by weight / volume%, so that itaconic acid alone could be used.
The red rot fungus could be exterminated in a short treatment time of 30 seconds. However, the treatment time could be further shortened to 10 to 20 seconds by using the acid of the present invention together. Therefore, the case where the concentration of itaconic acid is reduced and itaconic acid is used alone takes a long time is shown.

The concentration of itaconic acid was fixed at 0.2% by weight / volume, and 36% hydrochloric acid, 75% phosphoric acid and 90% lactic acid were individually changed between 0.1-0.3% by weight / volume. The seaweed leaves infected with the red rot fungus were immersed in the prepared seawater solution for a certain period of time shown in Table 6 and then taken out, washed with sea water and statically cultivated, and the state after 2 days was examined under a microscope. The extermination effect was investigated. Evaluation criteria are the same as those in Tables 4 and 5. The results are shown in Table 6.

[0035]

[Table 6]

When the concentration of itaconic acid is 0.2% by weight / volume, a treatment time of at least 2 minutes is required, and 0.1% of 36% hydrochloric acid, 75% phosphoric acid and 90% lactic acid are added thereto. ，
When 0.2, 0.3% by weight / volume% is used in combination, the combined acid is slightly insufficient at 0.1% by weight / volume, but 0.1
When used together in an amount of up to 0.3% by weight / volume, the red rot fungus can be eliminated in 60 seconds or less.

The concentration of itaconic acid was fixed at 0.1% by weight / volume, and 36% hydrochloric acid, 75% phosphoric acid and 90% lactic acid were individually changed between 0.1-0.3% by weight / volume. Using the seawater solution prepared as described above, the control effect against red rot fungus was investigated in the same manner as in Table 6 except for the above. Evaluation criteria are the same as in Tables 4-6.
The results are shown in Table 7.

[0038]

[Table 7]

When the concentration of itaconic acid is 0.1% by weight / volume, a treatment time of at least 4 minutes is required, and 0.1% of 36% hydrochloric acid, 75% phosphoric acid and 90% lactic acid are added thereto. ，
When used in an amount of 0.2, 0.3% by weight / volume, the red-rot fungus can be exterminated by the treatment within 3 minutes. Although 0.1% by weight / volume% of the combined acid is insufficient, 36% hydrochloric acid, 90% lactic acid, and 75% phosphoric acid are used in an amount of 0.2 to 0.3% by weight /
If used together in a volume percentage, the red rot fungus can be exterminated in 60 seconds or less.

Since the effects of the above-mentioned combined use of hydrochloric acid, phosphoric acid, and lactic acid may be suspected, each plain is treated as 0.
A comparative example is shown for the case of using 1, 0.2, 0.3% by weight / volume. After preparing a 0.1%, 0.2%, 0.3% by weight / volume% seawater solution of 36% hydrochloric acid, 75% phosphoric acid, and 90% lactic acid, dipping treatment was performed for a certain period of time shown in Table 8 and then taken out. After washing, static culture, microscopic examination of the condition after 2 days,
The control effect of red rot fungus was investigated. The treated water temperature and evaluation criteria are the same as in Tables 4-7. The results are shown in Table 8.

[0041]

[Table 8]

According to this result, the maximum effect of 0.
In the case of 3% weight / volume%, the minimum treatment time was 2 minutes for hydrochloric acid and phosphoric acid, and 50 seconds for lactic acid. However, treatment for a significantly long time is required, and it is clear from the results in Tables 4, 6 and 7 that it is not the effect of the combined acid alone or the effect of itaconic acid alone, but the synergistic effect of both. Is.

The above is the case where the processing temperature is 20 ° C.
Table 9 compares the case where the treatment temperature is 10 ° C. and the case where two or more kinds of itaconic acid, 75% phosphoric acid, 90% lactic acid and 30% hydrochloric acid are used in combination with the case where itaconic acid is 0.1% by weight / volume. Is. 1 min, 1.5 min, 2 min, 2.5 min, 3 min, 3.5 min of seaweed leaf infected with red rot fungus
After the immersion treatment for minutes, it was taken out, washed with seawater, and statically cultivated, and after 2 days, the state was observed under a microscope to examine the effect of controlling red rot fungi. The treated water temperature is 10 ° C. The evaluation criteria are the same as in Tables 4-8.

[0044]

[Table 9]

When the treatment temperature is 10 ° C., 0.1% by weight / vol% itaconic acid alone cannot disinfect it in 3.5 minutes, but when it is used in combination with 75% phosphoric acid and 90% lactic acid, it disinfects in 1 minute. It will be possible. At this temperature, the growth rate of red-rot fungi also drops significantly.

[0046]

EFFECTS OF THE INVENTION The red rot fungicide of the present invention has high bactericidal activity against red rot bacteria, but has low solubility in seawater, and itaconic acid is difficult to be made high in concentration. As for lactic acid, lactic acid, phytic acid and succinic acid, it is possible to use 6 or more of itaconic acid at a low concentration of 0.5% by weight / volume% or less by concomitantly using one or more kinds of acids having a long controlling time.
It was possible to exterminate the red-rot fungus in a short time treatment of 0 second or less, even at a low temperature, within 1 minute. Compared with the conventional disinfection work using citric acid, the work time can be greatly shortened, and it is also possible to disinfect it with a muzzle boat, so it is possible to prevent the total disappearance of seaweed due to red rot disease.

Claims (1)

[Claims] 1. Cultured seaweed containing at least one selected from the group consisting of hydrochloric acid, phosphoric acid, acetic acid, lactic acid, phytic acid and succinic acid in an aqueous solution of itaconic acid of 0.5% by weight or less. Red rot fungicides.