Levantamento e desenvolvimento de kit diagnóstico de patógenos e propagação in vitro de orquídeas no Estado do Rio de Janeiro

Abstract

It was conducted a survey of the major diseases that occur in orchids in the State of Rio de Janeiro, through collection of plants in various localities in the period April 2006 to June 2008. Fifty-three plants had their diseases and pathogens identified, of which 35.9% were infected by fungi, being 17% by Fusarium oxysporum, 13.2% by Colletotrichum gloeosporioides, 1,9% by Botrytis sp., 1,9% by Puccinia sp. and 1.9% by Phyllosticta capitalensis. 51% of the plants were infected by virus with simple and double infections of Cymbidium mosaic virus - CymMV and Odontoglossum ringspot virus - ORSV. 1.9% were infected by the bacterium Pectobacterium carotovorum subsp. carotovorum and 3.8% by nematodes of the genus Aphelenchoides. The nematodes Aphelenchoides fragariae and A. ritzemabosi were identified infecting hybrid orchids, which is the first report of parasitism of these nematodes in orchid and of A. ritzemabosi parasiting Asplenium nidus L. in Brazil. It also made the first record of the occurrence of Cymbidium mosaic virus - CymMV infecting Bamboo orchid Arundina bambusifolia Lindl. in the State of Rio de Janeiro. Based on the identification of pathogens of that survey, it was developed a diagnostic kit for the main diseases of orchids. Aiming to test antimycotic properties of three substances in culture medium for cultivation of orchids, using as test- plants Sophronitis cernua Lindl. and Epidendrum ellipticum Grah. Of the substances tested, only powdered cinnamon (Cinnamomum zeylanicum J. Presl), at the dose of 6 grams / liter positively influenced the germination of seeds of Epidendrum ellipticum Graham, and the addition of clove (Syzygium aromaticum) at doses of 3, 5 and 6 grams / liter caused the inhibition of in vitro germination of seeds of Epidendrum ellipticum Graham. and Sophronitis cernua (Lindl.) Hook. The addition of commercial garlic (Allium sativum L.) powder in doses of 6 and 10 grams / litre, also inhibited in vitro germination of seeds of Epidendrum ellipticum Graham.