What types of fungicides are commonly used for potted flowers?
Common fungicides for pest and disease control:
1. Chlorothalonil: It has protective and therapeutic effects, a broad fungicidal range, and a long residual effect, and it is irritating to the skin and mucous membranes. A 75% chlorothalonil wettable powder at 600-1000 times dilution is commonly used as a spray to control rust, downy mildew, powdery mildew, black spot, anthracnose, blight and other diseases. A 40% powder can also be dusted at 3-4 grams per sq m. It cannot be mixed with strongly alkaline pesticides, and it easily causes phytotoxicity to pear, persimmon, plum and so on.
2. Carbendazim: It is a highly effective, low-toxicity, broad-spectrum systemic fungicide with protective and therapeutic effects and a long residual effect. Generally, a 50% wettable powder at 1000-1500 times dilution is sprayed to control brown spot, sclerotinia rot, anthracnose, powdery mildew and other diseases; it can also be used for seed dressing and soil disinfection. When dressing seeds, the dosage is generally 2-3/1000 of the seed weight.
3. Bordeaux mixture: It is a good protective fungicide, prepared from copper sulfate, quicklime and water. According to the different amounts of copper sulfate and quicklime used, it can be divided into several types such as the equal formula (1:1), half formula (1:0.5), high formula (1:3) and double formula (1:2). When preparing, first dissolve the copper sulfate and quicklime separately in half of the water, then pour the copper sulfate into the quicklime solution and stir evenly with a stick. The prepared Bordeaux mixture is a sky-blue colloidal suspension, alkaline, with strong adhesion, and can form a film on the plant surface; its effective period can last about half a month. Bordeaux mixture does not keep well in storage and must be prepared and used immediately; it cannot be mixed with alkali-sensitive pesticides. It can control black spot, rust, downy mildew, gray spot and many other diseases.
4. Lime sulfur mixture: It is also a protective fungicide, made by boiling quicklime, sulfur powder and water in a ratio of 1:2:10. The stock solution is a dark reddish-brown transparent liquid with a rotten egg smell and is alkaline. When preparing, first boil the water in a pot, add 1 part quicklime, and after the lime dissolves, add 2 parts sulfur powder that has first been mixed into a paste with a small amount of water, stirring while adding. After adding, boil over high heat for about 1 hour, and when the liquid turns reddish-brown, stop the fire. After cooling, filter out the sediment to obtain the lime sulfur mixture stock solution, whose Baume degree is generally 20-24. The stock solution must be diluted before use; for spraying during the dormant period, Baume 3-5 degrees can be used, while during the growing period only a dilution of Baume 0.3-0.5 degrees can be used. It can control powdery mildew, rust, downy mildew, shot hole disease, leaf spot and many other diseases, and can also control pests such as whiteflies, spider mites and scale insects.
5. Thiophanate: It is a highly effective, low-toxicity, broad-spectrum systemic fungicide with protective and therapeutic effects and a long residual effect. Its fungicidal range and efficacy are similar to those of carbendazim, and it has low toxicity to humans and livestock and is safe for plants. A 50% wettable powder at 500-1000 times dilution is commonly sprayed to control powdery mildew, anthracnose, sooty mold, southern blight, sclerotinia rot, leaf spot, gray mold, black spot and other diseases; methyl thiophanate is also commonly used.
6. Zineb: It is a broad-spectrum organic sulfur fungicide, light yellow, with a slight odor, and it decomposes very easily in air or sunlight. A 65% wettable powder at 400-600 times dilution is commonly sprayed to control brown spot, anthracnose, damping-off, shot hole disease, gray mold, powdery mildew, rust, leaf blight, blight and so on. It cannot be mixed with alkaline agents or agents containing copper or mercury.
7. Tuzet: It is a mixed fungicide of organic arsenic and organic phosphorus, a white powder, poorly soluble in water, easily soluble in alkaline solutions, and easily decomposed in acidic, high-temperature and humid environments. Generally, a 50% wettable powder at 1000-1500 times dilution, or an 80% wettable powder at 2000-2500 times dilution, is sprayed to control anthracnose, rust, blight, powdery mildew, sclerotinia rot and other diseases.
8. Benlate: It is a broad-spectrum systemic fungicide with both protective and therapeutic effects. It is insoluble in water, has a slight irritating odor, and has a long effective period. A 50% wettable powder at 2000-5000 times dilution is commonly sprayed to control gray mold, anthracnose, powdery mildew, sclerotinia rot and other diseases.
9. Amobam: It has strong fungicidal power and both protective and therapeutic effects, and after decomposition it also has a certain fertilizing effect. It is a light yellow liquid. A 1000 times dilution is commonly sprayed to control powdery mildew, downy mildew and leaf spot, and a 200-400 times dilution can also be used to drench the soil to control blight.
10. Sulfur powder: It is a yellow powder with a distinct odor and has fungicidal and insecticidal effects. Its effective period is 5-7 days. A 50% powder is commonly dusted at 1-3 grams per sq m, or used for fumigation at 1 gram per sq m, and it can control powdery mildew.
11. Streptomycin: It is a white powder. Generally, a concentration of 100-200 milligrams per liter is sprayed, used as a root drench or injected, to control bacterial diseases, downy mildew and so on.