The symptoms such as soil compaction, pesticide or fertilizer excess, extreme temperatures, and moisture conditions indicate what kind of plant health issue?

• A. Infectious disease
• B. Nutritional deficiency
• C. Pest injury
• D. Noninfectious disease

Answer: (D)

Environmental or chemical factors cause problems in plants, not living pathogens. The symptoms described—soil compaction, excess fertilizer or pesticide residues, extreme temperatures, and moisture stress—are abiotic stresses that disrupt how a plant grows and functions rather than infections by fungi, bacteria, or viruses. These kinds of stresses can produce symptoms that look like disease, but they arise from the environment or chemical injury, so they’re considered noninfectious. Infectious diseases come from pathogens and typically show signs tied to the pathogen’s growth and spread, not just environmental or chemical stress.