VIEW ARTICLE

Cytology and Histology

Histology of Witches’-Broom Caused in Cacao by Crinipellis perniciosa. H. Calle, Director, Coffee Program, Instituto Nacional de Investigaciones Agropecuarias, Pichilingue, Ecuador; A. A. Cook(2), and S. Y. Fernando(3). (2)(3)Professor and laboratory technician, respectively, Department of Plant Pathology, University of Florida, Gainesville 32611. Phytopathology 72:1479-1481. Accepted for publication 21 April 1982. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-1479.

Mycelium of Crinipellis perniciosa was found throughout the cortex, phloem, ray, and pith of mature, green, and dry witches’-brooms of cacao (Theobroma cacao). The mycelia in green and dry brooms were composed of intercellular, uninucleate hyphae 4–9 μm wide that were branched, sometimes distorted and swollen, and septate with conspicuous walls. Dry brooms contained granular mycelia composed of binucleate and often intracellular hyphae (2–8 μm wide, with clamp connections) that originated by branching from a uninucleate mycelium. Host cells were in disarray in dry brooms, and uninucleate mycelium appeared to be intermixed with host cells. No mycelium was found in healthy tissues to which brooms were attached. Arthrospores (6–7 × 5 μm) were observed in dry brooms.