See:
Raspberry (Rubus spp.) - Verticillium Wilt
Blackberry Cultivar Susceptibility
Note: The disease is found more often in the cultivars 'Loganberry' and 'Youngberry' than in the 'Marion' and 'Evergreen' trailing berries.
This 'cole' blackberry had Verticillium, poor growth and failed to set fruit as well as cane and leaf symptoms.
See:
Raspberry (Rubus spp.) - Verticillium Wilt
Blackberry Cultivar Susceptibility
Note: The disease is found more often in the cultivars 'Loganberry' and 'Youngberry' than in the 'Marion' and 'Evergreen' trailing berries.