ISDA Seed Treatment Practice Test 2026 – The All-In-One Guide to Master Your Certification!

The correct answer focuses on Pythium and Rhizoctonia, which are notorious for causing seed rot in various crop species. Pythium is a water mold that thrives in moist soil conditions and can infect seeds, leading to rot before they even germinate. It affects seeds by causing decay that inhibits germination and can lead to damping-off disease in seedlings. Rhizoctonia, a soil-borne fungus, is also responsible for seed rot and affects various plant species by causing pre-emergence and post-emergence damping-off, resulting in seedling death.

Understanding the specific mechanisms through which these pathogens operate helps in managing and preventing seed rot effectively. Both Pythium and Rhizoctonia not only contribute to the immediate decline in seed viability but also create conditions that can affect plant health later in the growing season. Therefore, effective seed treatment measures are crucial to mitigate these pathogens' impact on seed health.