What type of chemicals are applied to foliage, flowers, and fruit for protection?

The focus of the question is on the application of chemicals directly onto plants—specifically foliage, flowers, and fruit—to provide protection against pests or diseases. The term "protective chemicals" aptly describes this function, as these substances are specifically designed to shield plant surfaces and improve their health and resilience against various threats.

The term encompasses a variety of chemical types, including fungicides, insecticides, and miticides, which are formulated to create a barrier or provide systemic protection once applied. This makes "protective chemicals" the most fitting descriptor for products aimed at enhancing the well-being of visible plant parts.

In contrast, systemic chemicals typically refer to substances that are absorbed by plants and transported throughout their tissues rather than just being applied to surfaces. Pesticides is a broader category that includes protective chemicals but doesn't limit itself specifically to those applied externally. Soil amendments focus on improving soil quality rather than protecting the plant itself from above ground threats. Thus, the definition of protective chemicals aligns perfectly with the purpose outlined in the question.