What is phytotoxicity in the seed treatment context?

• A. Injury to seed or seedling caused by pesticides.
• B. Increased germination rate due to treatment.
• C. Reduction in seedling height due to weather only.
• D. Enhanced vigor from seed treatments.

Answer: (A)

Phytotoxicity is plant injury caused by chemicals. In the seed treatment context, it means the seed or the very young seedling is harmed by the pesticide or other chemical applied to the seed. This can occur when the product rate is too high, when seed treatment combinations are incompatible, or when environmental conditions favor uptake of the chemical. Symptoms can include seedling scorch, yellowing (chlorosis), necrosis, reduced germination, or poor emergence. It’s a negative effect, in contrast to outcomes like higher germination or increased vigor, which are not phytotoxicity. Proper labeling, rate decisions, and sometimes testing on a small scale help prevent such injury.