flétrissure fusarienne de la laitue

CONT: Fusarium wilt of lettuce. Symptoms. The first symptoms of Fusarium wilt may occur as early as thinning, when some seedlings wilt and die. Infected plants display a characteristic red-brown streak extending from the upper taproot into the cortex of the crown. Older affected heads exhibit a tipburn that may often be limited to one side of the plant. Yellowing of leaves and a brown to black streaking of the foliar vascular tissue is often present.