What type of nutritional strategy does apple scab employ?

Apple scab, caused by the fungus Venturia inaequalis, employs a necrotrophic nutritional strategy. In this type of strategy, the pathogen kills host plant cells to extract nutrients for its growth and reproduction. The fungus penetrates leaf tissues and induces cell death, creating a suitable environment for nutrient acquisition from the decaying plant tissues.

This necrotrophic behavior allows Apple scab to thrive on the dead plant material, which is necessary for its development and spread. The symptoms of apple scab, such as dark, olive-green lesions on leaves, further illustrate how the fungus damages the host plant by compromising its tissue integrity.

In contrast, biotrophic pathogens rely on living host tissues for survival and typically do not kill the host cells immediately. Saprophytic organisms feed on dead organic matter without a live host. Symbionts form beneficial relationships with their hosts, often enhancing the host's nutrient uptake instead of causing harm. Understanding the nutritional strategy of apple scab helps in developing better management practices to control its impact on apple crops.