Verticillium wilt of cacao in Uganda: symptoms and establishment of pathogenicity

Abstract

SUMMARY Pathogenicity tests have shown that Verticillium dahliae Kleb. causes a vascular wilt disease of cacao ( Theobroma cacao L.) in Uganda. Isolates of V. dahliae from cacao, okra ( Abelmoschus esculentus Medik.), and cotton ( Gossypium hirsutum L.) induced similiar symptoms on artificially inoculated cacao seedlings. External symptoms of the disease include acute wilting, foliar chlorosis and abscission, stunting of roots and shoots, and production of suckers at lower nodes of severely affected plants. The internal symptoms are vascular discoloration, tylosis, and presence of gum deposits and mycelium of V. dahliae in xylem vessels.