is rust pustule a plant symptom or sign

Answer 1

Rust pustule is a symptom of a plant disease, typically caused by fungi belonging to the order Pucciniales, known as rust fungi. These fungi infect a variety of plants and produce characteristic rust-colored pustules (uredinia) on leaves, stems, or other plant parts. The presence of these pustules indicates an infection, which can lead to reduced vigor, lower yields, and ultimately, damage to the plant if not managed effectively. Signs of the disease would refer to the actual rust fungi or their structures that can be observed, such as spores or mycelium.