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What is Polyetic disease cycle?

Epidemics that occur under these conditions are referred to as polyetic epidemics and can be caused by both monocyclic and polycyclic pathogens. Apple powdery mildew is an example of a polyetic epidemic caused by a polycyclic pathogen and Dutch Elm disease a polyetic epidemic caused by a monocyclic pathogen.

What are the four phases of growth for an epidemic in plants?

Each cycle consists of four phases: infection, latency, sporulation, and dispersion.

Do pathogens need light growth?

In all plant–pathogen interactions, however, light apparently is required for the activation of downstream SA-mediated defense responses. In particular, light is required for the hypersensitive response (HR), a form of localized programmed cell death at the site of infection, activated during ETI.

What is monocyclic disease of plant?

The Cyclical Nature of Plant Disease Pathogens that produce only one cycle of development (one infection cycle) per crop cycle are called monocyclic, while pathogens that produce more than one infection cycle per crop cycle are called polycyclic.

What are Biotrophs and Necrotrophs?

Biotrophs are pathogens that derive nutrients from living host tissues, and necro-trophs are pathogens that derive nutrients from dead or dying cells (4). Some pathogens can be clearly assigned as biotrophs or necrotrophs.

How do you control monocyclic disease?

In general, monocyclic diseases are most efficiently suppressed by reducing the amount of the initial inoculum during the first and last events.

What is monocyclic disease?

What is difference between disease cycle and life cycle?

The life cycle of an infectious disease is the sequence of distinct events, such as sexual reproduction, that occur between the appearance and reappearance of the causal organism. The stages of the disease cycle are the appearance, development and perpetuation of a pathogen and the effect of the disease on the host.

What does pathogens need to grow?

Foodborne pathogens grow best in temperatures between 41 to 135 °F (5 to 57 °C), a range referred to as the temperature danger zone (TDZ). They thrive in temperatures that are between 70 to 104 °F (21 to 40 °C). Almost all foodborne pathogens are aerobic, that is requiring oxygen to grow.

Do microorganisms grow in dark?

Some bacteria can survive harsh conditions for decades or even centuries. Bacteria grows best in warm, moist, dark places. Of the thousands of bacterial species on the earth, only a small fraction cause disease.

What makes a monocyclic disease an epidemic disease?

Monocyclic disease epidemics are resulted in by those pathogens that are restricted to one generation per cropping season; such pathogens are said to be monocyclic. The latter possess a life cycle that occupies about one season and have no repeating reproductive stages (secondary cycles) of shorter duration.

When do monocyclic pathogens follow the Black Arrows?

The monocyclic pathogen follows the black arrows to complete its cycle. Polycyclic pathogens follow the red arrows for the majority of the season and the black arrows at the end of the season. In order for a disease to develop, a pathogen must be present and successfully invade plant host tissues and cells.

How is the severity of polycyclic pathogens determined?

Polycyclic Pathogens: -have a secondary cycle -disease severity is primarily determined by -rate of pathogen reproduction, and -spread of the pathogen. -Initial inoculum is also a determining factor, but not as important as in the monocyclic pathogens.

How did the monocyclic and polyetic phases develop?

The monocyclic phase developed due to over-summering of pathogen inoculum and was the source of primary infection, whereas polyetic phase developed from root-to-root contact and was the source of secondary infection.