How to Manage Pests

Seasonal development and life cycle—Verticillium wilt

The fungus that causes Verticillium wilt can survive for years in the soil. It enters the tree through young roots, establishing itself in the water-conducting tissues of the plant, and renders the xylem vessels no longer functional. Cool spring weather is most favorable for disease development. High summer temperatures actually kill the fungus in the tree. If new infection through the roots does not occur, trees recover and grow normally the next year. Although the pathogen may reside in roots for a period of time, old infections eventually die. Once roots have penetrated below the level of inoculum in the soil, new infections will not occur and symptoms will virtually disappear.

Discolored vascular tissue