Department of Plant Pathology, Agricultural Research Organization, 85280 M. P. Negev, ISRAEL
Verticillium dahliae caused wilting, stunting and early dying of paprika plants in Israel, resulting in a 22% reduction in yield. A V. dahliae isolate from diseased paprika plants was slower growing on agar medium than V. dahliae isolates from potato, tomato, watermelon, and Dodonaea, but formed microsclerotia earlier. The paprika isolate of V. dahliae was highly virulent to paprika in pathogenicity tests. Disease severity indices obtained from three paprika cultivars ranged from 3.7 to 4.9 (on a scale of 0 to 5). The disease caused height reductions of 43 to 62% in the three inoculated paprika cultivars, and pathogen colonization levels were 10- to 35-fold higher in stems than in leaves. The potato isolate of V. dahliae did not produce symptoms or cause stunting of paprika, and could not be detected in stems or leaves. The tomato, watermelon, and Dodonaea isolates did not cause disease symptoms in paprika, although they colonized the plant tissue. In potato and eggplant, the paprika isolate caused a higher incidence of disease with more severe symptoms and a higher level of tissue colonization than did the potato isolate.