J. Phytopathology 135, 37—47 (1992) © 1992 Paul Parey Scientific Publishers, Berlin and Hamburg ISSN 0931-1785 Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz, Iran Etiology and Transmission of Sesame Phyllody in Iran M. SALEHI and K. IZADPANAH«- Authors' addresses: M. SALEHI, Plant Pest and Disease Research Laboratory, Zarghan, Iran. K. IZADPANAH, Department of Plant Protection, College of Agriculture, Shiraz University, Shiraz, Iran. With 9 figures Received July 12, 1991; accepted August 21, 1991 Abstract Phyllody is a destructive disease of sesame {Sesamum indicum L.) in Iran. The major symptoms of the disease are floral virescence, phyllody and proliferation. Other symptoms which sometimes accompany the disease are yellowing, cracking of seed capsules, germination of seeds in the capsules and formation of dark exudates on the foliage. Light microscopy of hand-cut sections of sesame and colza {Brassica napus L. cv. Oro) stems treated with Dienes' stain showed blue areas in the phloem region of phyllody infected plants. Mycoplasma-like bodies were found in the sieve cells of infected sesame stems when thin sections were examined in an electron microscope. Sesame phyllody was successfully transmitted from sesame to sesame by grafting. Among various leafhoppers collected in sesame fields only Neoaliturus haematoceps transmitted the disease. This is the first report on the identification of a Mycoplasma-like organism (MLO) as the cause of sesame phyllody and N. haematoceps as an MLO vector in Iran. In host range studies using the leafhopper vector, only B. napus cv. Oro, Lepidium sativum, Catharanthus roseus, Lactuca sp. and Portulaca oleracea, but not 17 other species, developed symptoms. The species of vector and host range of MLO indicate that sesame phyllody in Iran is different from that reported in India and Upper Volta. Zusammenfassung Atiologie und Ubertragung von Sesamphyllody in Iran Im Iran ist Phyllody eine vernichtende Krankheit des Sesams {Sesamum indicum L.). Die Hauptsymptome der Krankheit sind Bliitenvireszenz, -phyllody und -wuchern. Andere Symptome, die die Krankheit manchmal begleiten, sind Vergilbungen, ein Aufplatzen der Schoten, Samenkei- •'" To whom correspondence should be addressed. U.S. Copyright Clearance Center Code Statement: 0931-1785/92/3501-0037$0230/0