Which of the following is a primary symptom associated with Sclerotium sp. infections?

The primary symptom associated with Sclerotium sp. infections is the yellowing of plant tissues. Sclerotium species, particularly Sclerotium rolfsii, are known to cause a range of symptoms in infected plants, and yellowing is often one of the first visible indications of their presence. This yellowing occurs as the pathogen affects the plant's ability to take up nutrients and water, leading to physiological stress and chlorosis in the leaves.

In contrast, while stunted growth, root rot, and leaf curl can all occur in a variety of plant diseases, they are not specifically associated with Sclerotium infections. Stunted growth may result from several other stress factors, root rot often implies different pathogens or issues, and leaf curl is typically linked to viral infections or other specific types of fungal pathogens. Thus, recognizing yellowing as a key symptom helps in correctly identifying Sclerotium-related infections and taking appropriate pest management actions.