Avoid Stress at Emergence

Disease Progression vs Emergence chart

Factors that inhibit ideal emergence and promote seedling disease include extended cool and wet conditions or exceptionally dry or crusted seedbeds following planting. Some springtime seedbed scenarios have heavy inoculum pressure where disease progression competes with seedling growth. Conditions that promote rapid soil warming are generally favorable for seedling growth while reducing the likelihood of disease development. In contrast, stresses posed by extended cool and wet conditions favor disease development as illustrated in the graph.

Injury to emerging seedlings will also promote seedling disease. Injury can be caused by chilling, such as imbibitional damage, or by feeding of insects such as seedcorn maggots, white grubs and wireworms.