Which active ingredient is commonly used in seed treatments to control damping-off and seed rot?

• A. Thiabendazole
• B. Fludioxonil
• C. Mefenoxam
• D. Thiram

Answer: (B)

Preventing seedling diseases like damping-off and seed rot relies on applying a protective fungicide directly to the seed so it guards the germinating seed as it encounters soil-borne fungi. Fludioxonil is used widely because it provides strong, preventative protection on the seed surface against the major damping-off pathogens (such as Pythium and Rhizoctonia) and is often combined with other actives to broaden the spectrum. This gives reliable stand establishment right after planting. Other actives exist but have narrower targets or limitations: for example, mefenoxam mainly targets Pythium and Phytophthora, while thiabendazole and thiram can be less effective across the full range of damping-off pathogens or have safety/use considerations.