| Verticillium wilt, caused by Verticillium dahliae, is a severe problem in strawberry production in California. In this study, strawberry plots were artificially inoculated with microsclerotia of V. dahliae (0, 1, 3, 5, 10, 15, 20 and 30 microsclerotia per g soil). Plant growth was measured and disease severity was rated from April to October for two years. Marketable fruit yield was recorded at every (commercial) harvest. A significant negative effect of inoculum density on plant growth rate was observed. At an inoculum density of five microsclerotia per g soil marketable yield was reduced by approximately 24% over uninoculated controls. Inoculum levels as low as three microsclerotia per g soil were associated with moderate disease severity (noticeably wilted with at least one whorl of dead outer leaves) and ≥ ten microsclerotia per g soil were associated with yield losses of 47-63%. |
