PATHOGENICITY OF RACE-1 AND RACE-2 TOMATO WILT ISOLATES OF VERTICILLIUM-DAHLIAE TO 4 SOLANACEOUS AND 2 NON-SOLANACEOUS HOSTS

The pathogenicity of four race-1 and three race-2 tomato wilt isolates of Verticilium dahliae to tomato, eggplant, tobacco, pepper, French b ean and cabbage was investigated. Plants were inoculated without wound ing and the symptoms assessed 6 weeks later. Both race-1 and race-2 is olates caused foliar symptoms on the race-1 susceptible tomato cultiva r GCR-26 (Ve/Ve) although these were generally more severe with race-1 . All race-2 isolates were significantly more pathogenic than race-1 o n the race-1 resistant tomato cultivar GCR-218 (ve/ve), although two o f the race-1 isolates caused mild foliar symptoms. None of the race-2 isolates caused stunting of GCR-26 whereas they all caused significant stunting of GCR-218. All isolates reduced dry weight on GCR-26 wherea s only race-2 affected GCR-218. All isolates induced significant folia r symptoms, stunting and reduction in dry weight on eggplant. Only one isolate (race-1) caused foliar symptoms on tobacco but this was not a ccompanied by a reduction in either plant height or dry weight. All is olates were able to cause foliar symptoms on pepper, and two caused mo derate to severe symptoms. Four isolates caused a significant reductio n in plant height and one of these reduced dry weight. One isolate whi ch caused mild foliar symptoms on pepper increased host dry weight. No disease symptoms were observed on the non-solanaceous host French bea n. All isolates were capable of inducing mild foliar symptoms on cabba ge but none caused reductions in either plant height or dry weight. Ra ce-1 and race-2 isolates could only be distinguished on the near-isoge nic pair of tomato cultivars. Verticillium was re-isolated for each fu ngal isolate/host cultivar combination for tomato, eggplant and tobacc o but was sporadic for the other hosts.