What is phytotoxicity in the context of seed treatments?

• A. Seed coloration change.
• B. Beneficial growth promotion.
• C. Non-toxicity.
• D. Injury to seeds or emerging seedlings caused by the chemical, often due to high rate, poor compatibility, or temperature stress.

Answer: (D)

Phytotoxicity in seed treatments means injury to the seed or the emerging seedling caused by the chemical in the treatment. This can occur when the application rate is too high, when the product is not compatible with other components of the seed coating, or under temperature stress that alters how the chemical interacts with the seed. Symptoms can include poor germination, uneven emergence, and visible damage such as discoloration or necrosis in the seedling tissues. The other options describe changes or effects that are not about chemical injury to the plant, so they don’t capture what phytotoxicity is. In practice, prevent it by following label rates, testing compatibility with other products, and considering environmental conditions during application.