When is the black knot fungus most active in terms of infection?

The black knot fungus, which primarily affects cherry and plum trees, is most active in the spring. During this season, the conditions are favorable for the fungus to thrive and spread. The warmer temperatures and the presence of moisture from spring rains provide an ideal environment for the fungal spores to germinate and infect new plant tissue.

As the buds begin to swell and trees enter a period of active growth, their susceptibility to pathogens like black knot increases. If the fungus successfully infects the trees during this time, it can lead to the characteristic black, knotted growths that are a hallmark of this disease.

In contrast, summer tends to see a more stable environment after the initial spring infection period, while fall may result in a slow-down of the fungal activity as temperatures start to drop. Winter, on the other hand, typically sees the fungus in a dormant state, as cold temperatures and lack of moisture limit its activity. Understanding the seasonality of black knot fungus helps in managing its control and preventing its spread effectively.