Bald heads refer to seedlings that emerge with damaged or no growing point. Cotyledons (seed leaves) may or may not be present. Plants may develop auxiliary buds at the base of cotyledons but they fail to develop. Without a growing point, plants eventually die. The most common cause of bald heads is mechanical damage to seed or harsh handling. Damage is characterized by cracks in the seed coat. Poor quality seed can also cause seedlings to have broken or cracked cotyledons. Seed with moisture content below 16% is more prone to mechanical damage. Injury should not be confused with symptoms of seed corn maggots, which will leave the seedlings ragged in appearance.
Use only high-quality certified seed for planting. Treat seed with a fungicide at planting to protect against seedling disease and handle gently to minimize mechanical damage.