In early summer the fungus can be readily isolated from diseased tissue in infected trees. When replanting in an area where susceptible perennials were previously grown, remove as many roots of the trees or vines as possible. Beginning in late spring cover the surface of an entire block with transparent plastic that has a UV-inhibitor additive. Leave the plastic on throughout the summer and as long as practical. Inferior plastic will break down and render the treatment ineffective.
Solarization gives inconsistent results when used in replant spots.
Dry soil by withholding water during summer and using cover crops not susceptible to Verticillium wilt such as sudangrass. The drier the soil, the better for deep penetration of methyl bromide. Deep-till the area after drying. If the soil is dusty, wait for an early rain before ripping and fumigating. Ripping a dry soil that is silty can result in large clods on the surface.