Symptoms and Disease Cycle
Strawberry plants are most susceptible in their first year of growth. Initial symptoms appear rapidly in late spring, especially in periods of environmental stress. The outer and older strawberry leaves wilt and dry, turning a reddish yellow to dark brown at the margins and between the veins. The inner leaves remain green and turgid until the plant dies. This symptom helps distinguish verticillium wilt from the root and crown diseases caused by Phytophthora species, in which both the young and mature leaves wilt. The disease intensity may depend on fertilization practices and the amounts of "residual" field inoculum left from previous crops. Plants with lush growth due to high nitrogen applications are more severely affected than plants receiving moderate amounts of nitrogen. Previous crops of Solanaceous plants (e.g., tomatoes, potatoes, eggplant) might have harbored the pathogen and caused a buildup of soil inoculum. It is advisable not to plant a new strawberry bed following crops of this family.
Planting resistant varieties and disease-free plants will help control verticillium wilt. A rotation schedule of 3 to 5 years also is recommended.
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