Which environmental factor can affect the onset of diseases?

Temperature and humidity play a significant role in the development and onset of diseases in turfgrass. These environmental factors create conditions that can either promote or inhibit the growth of pathogens. For instance, high humidity levels can increase moisture on the leaf surfaces, creating an ideal environment for fungal diseases to thrive. Similarly, certain temperatures can favor specific pathogens; for example, warm, humid conditions may lead to outbreaks of diseases like brown patch or dollar spot. Understanding the interplay of temperature and humidity, therefore, is crucial in managing both pest populations and disease incidence effectively within turfgrass systems. This knowledge aids in implementing preventative measures, such as appropriate watering practices and fungicide applications, based on the forecast of these environmental conditions.

Other factors listed, while they may influence turfgrass health, do not have as direct an impact on the onset of diseases as temperature and humidity do. Soil pH is important for nutrient availability, time of day mainly affects photosynthesis and physiological processes, and color of the soil does not have a recognized direct relationship with disease onset in cool-season grasses.