Illinois Pesticide Applicator Practice Test

What are the three essential components required for the development of an infectious plant disease?

1. Chemical agent, Resistant host, Time

2. Favorable environment, Susceptible host, Pathogen

3. Pathogen, Fertilizer, Host

4. Water, Light, Pathogen

The correct answer is: Favorable environment, Susceptible host, Pathogen

The essential components required for the development of an infectious plant disease are a favorable environment, a susceptible host, and a pathogen. Each of these components plays a critical role in the establishment and progression of the disease. A favorable environment refers to the specific conditions that promote the growth and reproduction of the pathogen, as well as the susceptibility of the host plant. Environmental factors such as temperature, humidity, and soil conditions can influence the likelihood of a disease outbreak. A susceptible host is a plant that does not have the necessary defenses to resist the infection. Different plant species have varying levels of resistance or susceptibility to specific pathogens, meaning that certain plants may readily develop a disease if the pathogen is present. The pathogen itself is the organism, such as a bacterium, fungus, or virus, that causes the disease. For an infectious disease to develop, the pathogen must be capable of infecting the susceptible host under the right environmental conditions. Together, these three components create the conditions necessary for an infectious plant disease to manifest, highlighting their interdependent roles in the disease cycle.