Which fungicide is effective in treating black rot?

Spectracide Immunox® is effective in treating black rot because it contains the active ingredient myclobutanil, which is a systemic fungicide. This specific type of fungicide works by being absorbed into the plant's tissues and providing protection against fungal diseases, including black rot. Myclobutanil targets various types of fungal pathogens and helps to control their growth and spread, making it particularly useful for managing diseases like black rot.

Other options such as Sevin and Tribufos do not have the appropriate fungicidal properties to control black rot, as they are primarily insecticides or related to pest control rather than effective treatments for fungal infections. Ethephon is a plant growth regulator and not a fungicide, meaning it does not target or control fungal diseases effectively. Therefore, Spectracide Immunox® stands out as the choice specifically designed to combat black rot in plants.