Abstract

ACOSTA-PEREZ, JA et al. Identification of the causal agent and importance of gummosis in the citrus region of Huimanguillo, Tabasco, México. Universidad y ciencia [online]. 2012, vol.28, n.3, pp.245-258. ISSN 0186-2979.

This study was carried out to identify the species of Phytophthora that causes gummosis or rot of the foot in Valenciana orange (Citrus sinensis) and Persa lemon (C. latifolia) crops in the Sabana de Huimanguillo, Tabasco. Of 34 sites that were sampled systematically, 13 isolates of Phytophthora were obtained from diseased stem and fruit tissues. For this, a selective carrot agar medium (10 % carrot-agar Rifampicin, Pimarycin, Vancomycin, Pentachloro-nitrobenzene (PCNB) and Benlate were used. The morphological characterization of these isolates presented torulous coenocytic mycelium, papillate sporangia, intercalar and terminal chlamydospores; according to the morphological keys of Stamps et al. (1990) they belong to the species P. parasitica without P. nicotianae var. parasitica. This was confirmed by molecular identification. This is the first report of P. parasitica attacking C. sinensis and C. latifolia crops in Tabasco. It may also be pointed out that based on the evaluation of the 34 farms that were visited, the incidence of gummosis is 17.5 % with a variation range of 1.4 to 45 %, with the greatest damage in the C. latifolia crops and the least in the C. sinensis crops. It may also be indicated that the C. latifolia crops are presenting a new disease with external symptoms similar to gummosis and the producers are wrongly dealing with it as if it were gummosis. This disease was present in 44 % of the C. latifolia crops with an average incidence of 10.2 % and a range of 1.7 to 25 %.

Keywords : Phytophthora parasitica; Citrus latifolia; molecular and morphological characterization.

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