When should fungicides be applied to prevent stem rot?

Applying fungicides in early spring is the most effective strategy for preventing stem rot. This timing is crucial because many fungi that cause stem rot are most active in moist, warm conditions, which commonly occur in the spring as temperatures rise and rainfall increases. By applying fungicides during this period, you are proactively managing the disease before it can establish itself in the plants.

Additionally, early spring applications can help protect new growth, which is particularly susceptible to disease. This preventive measure also aligns with the growth cycle of many ornamental plants, allowing them to develop strong defenses against potential infections throughout the growing season.

The other options, such as fall or winter applications, may come too late in the season to effectively prevent the disease from taking hold. Late summer applications also may not be timely enough, as stem rot can already be established or be favored by environmental conditions as the season progresses. Therefore, early spring stands out as the optimal choice for applying fungicides to combat stem rot effectively.