Which of the following is NOT a factor of pathogenic disease?

The correct answer is identified as beneficial fungi because they do not contribute to pathogenic diseases. In the context of plant health and disease, beneficial fungi typically engage in symbiotic relationships with plants, enhancing nutrient uptake and providing protection against harmful pathogens. They are an important part of healthy soil ecosystems and contribute positively to plant health.

In contrast, the other factors listed are integral components of pathogenic disease. A susceptible host is crucial, as it is the plant or organism that can be infected or affected by a pathogenic organism. The presence of a parasitic organism, which can be a fungi, bacteria, or virus, is essential for the disease to occur as these are the pathogens that cause harm. Lastly, environmental conditions play a significant role in the development and spread of plant diseases, as factors such as moisture, temperature, and light can influence the activity of pathogenic organisms. Understanding these elements helps in managing plant health and preventing diseases effectively.