JPH0122242B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a control agent for red rot fungi or green seaweed. Ru. Seaweed farming technology has made great progress with the practical use of artificial seedling collection, the widespread use of floating culture methods, and the development of a method for storing seaweed nets in refrigeration. However, the development of special drugs to control diseases such as red rot and chyme fungus has lagged behind, and there are no known practical drugs. When red rot occurs, the quality and yield of seaweed decreases, and in some cases, no production at all. Furthermore, in areas where green seaweed tends to grow, green seaweed can be mixed into dried seaweed products, reducing the quality of the seaweed, so there is a desire to develop a chemical that can control green seaweed. Methods for controlling red rot include using a combination of inverse soap and a bromosalicylanilide compound (see Japanese Patent Publication No. 11400/1983), and using antibiotics such as streptomycin (see Japanese Patent Publication No. 12652/1982). ) and a method using p-oxybenzoic acid (see Japanese Patent Publication No. 46-35873) are known. However, antibiotics are expensive, inverse soaps (surfactants) are toxic, and p-oxybenzoic acid has low solubility in water, all of which have problems in practical use. The present invention is a control agent for red rot bacteria or green seaweed for seaweed netting, which contains chlorine dioxide as an active ingredient. Although conventional red rot fungus control agents have no controlling effect on green seaweed, the control agent of the present invention can also control green seaweed. Chlorine dioxide, which is the active ingredient of the pest control agent of the present invention, is stable and inexpensive as an aqueous solution, and has already been approved as a food additive in the United States and is recognized as safe. The efficacy of the pesticidal agent of the present invention is largely influenced by pH, and is fully effective at pH 4.5 or lower, particularly pH 3.5 or lower. Acids for adjusting pH include organic acids such as phytic acid, citric acid, and malic acid, or phosphoric acid;
Inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid are used. Preferably, the pesticidal agent of the present invention is in the form of an aqueous solution. The chlorine dioxide concentration of this preparation is usually 1~
It is 10% by weight. This solution is obtained by bubbling a certain amount of chlorine dioxide into water. It is preferable that the pesticidal agent of the present invention further contains a fertilizer component of seaweed. Fertilizer components include inorganic fertilizers such as sodium nitrate and disodium hydrogen phosphate, and organic fertilizers such as amino acids, sugars, and vitamins. The growth of seaweed can be promoted by using a pest control agent containing fertilizer components. The method of using the pest control agent of the present invention is to dilute the pest control agent with seawater and then add acid to prepare a treatment solution with a chlorine dioxide concentration of 50 to 200 ppm and a pH of 3.5 or less.
It is preferable to immerse the seaweed net in this treatment liquid.
Soaking time is usually 10-30 minutes. In addition, a treatment liquid containing relatively high concentration of chlorine dioxide may be sprayed onto the seaweed net. Since the chlorine dioxide used in the present invention is originally a gas and a considerable amount evaporates after use, it has almost no impact on the ocean. Test Example 1 Seaweed infected with red rot bacteria was collected from the Ariake Sea fishing grounds and immersed in a chlorine dioxide seawater solution of a predetermined concentration for 15 minutes. The treated seaweed thallus was transferred to a shear tray containing healthy thallus (thallus grown by artificial culture). After 48 hours, healthy leaves were removed and examined for the presence of red rot fungi to determine their control effectiveness. The pH of the chlorine dioxide solution was adjusted with citric acid and caustic soda. The results are shown in Table 1.

[Table] Test Example 2 A seaweed net mixed with green seaweed from the Ariake Sea fishing ground was used in the test. To each concentration of chlorine dioxide seawater solution 100,
One piece of seaweed net was soaked for 15 minutes in each case. 3 days later,
The degree of decolorization of green seaweed was examined to determine its pesticidal effect.
Note that the pH was adjusted with citric acid and caustic soda. The results are shown in Table 2.

【table】

[Table] Test Example 3 The pesticides of Examples 1 and 2 were diluted 200 times with seawater, and the pH was adjusted to 3.5 with a 10% phytic acid solution. After immersing the seaweed fronds in this solution for 15 minutes, they were artificially cultured indoors. After 5 days, the elongation rate and degree of injury of the seaweed were examined and compared with the control (untreated). The elongation rate was determined by setting the elongation rate of the control as 100. In addition, the degree of injury was determined by staining with an erythrosin solution for 1 minute. The results are shown in Table 3. It is known that when the pesticidal agent of the present invention is applied to seaweed leaves, the growth of seaweed is improved. This is thought to be because chlorine dioxide controls not only red rot bacteria but also filamentous fungi that adhere to the surface of the seaweed leaves and improves the absorption of nutrients. Furthermore, the effect can be further enhanced by using a chlorine dioxide solution containing fertilizer.

[Table] Example 1 A 2% chlorine dioxide aqueous solution manufactured by Nippon Clement Co., Ltd. was used as a pest control agent. Example 2 2% chlorine dioxide aqueous solution 100 manufactured by Nippon Clement Co., Ltd.
5 parts of sodium nitrate and 5 parts of disodium hydrogen phosphate are dissolved in 5 parts of sodium nitrate to prepare a pest control agent.

Claims (1)

[Scope of Claims] 1. A control agent for controlling red rot bacteria or green seaweed for seaweed netting, which contains chlorine dioxide as an active ingredient. 2. The pesticidal agent according to claim 1, which contains a fertilizer component.