What is a symptom of excessive sunlight exposure on plants?

Sunscald is a symptom that occurs when plants are exposed to excessive sunlight, particularly when the intensity is significantly higher than what they can acclimatize to. This condition can result in damage to the plant's tissues, especially in sensitive areas like the leaves or stems. Sunscald leads to symptoms such as discoloration and browning of the plant tissues, which can eventually progress to tissue death.

In the case of sunscald, it often manifests as bleached or sunburned patches on leaves and stems, indicating that the plant is unable to cope with the intense light and heat.

The other symptoms listed do not specifically result from excessive sunlight exposure. Necrosis of roots is usually associated with overwatering, poor drainage, or root diseases. Leaf miner damage involves insects that burrow through leaves, not a result of light exposure. Fungal growth typically thrives in conditions of high humidity or moisture, not directly from sunlight intensity. Therefore, sunscald clearly identifies the issue of excessive sunlight exposure affecting plant health.