Phytophthora spear rot is characterized by soft, water-soaked lesions on shoots near the soil line. The lesions elongate rapidly and become light brown. As the lesion collapses and shrivels, the affected side of the spear becomes flattened, and the shoot becomes extremely curved and may even collapse. Infected crowns have yellow orange colored tissue. The tissue may appear waterlogged and fibrous.
Solutions
Crown and spear rot is most common in wet years. Avoid prolonged saturation of the soil and provide good drainage. Irrigate only as much and only as often as necessary. Plant in Phytophthora-free soil and use disease-free transplants.
For more information, see the Phytophthora Root and Crown Rot Pest Note.
