Plants infected with Sclerotinia crown and stem rot continue to die. Due to infection by Pythium and Phytophthora, early seedings may exhibit damping-off symptoms in cool, wet soils. Lepto leaf spot can be active now, especially on plants that are regrowing after a late freeze. When frost injury is followed by wet weather, bacterial stem blight also may occur. Spring black stem and leaf spot can be found during wet weather periods.
Plants infected with Sclerotinia crown and stem rot continue to die.
Because Sclerotinia goes dormant when the plants are killed, fields with severe outbreaks of Sclerotinia crown and stem rot can be resown to alfalfa if the entire stand has been dead for several weeks. Spring black stem and leaf spot can be common. Late cases of bacterial stem blight develop during extended periods of cool, wet weather. For plants with any of the foliar diseases, take the first cutting of alfalfa as soon as it is agronomically acceptable. Sclerotinia crown and stem rot activity tapers off.