Resumo

SAMANIEGO-GAXIOLA, José Alfredo. Effect of pH on survival of sclerocia of Phymatotrichopsis omnivora (Dugg.) Hennebert exposed to Tilt and Trichoderma sp.. Rev. mex. fitopatol [online]. 2008, vol.26, n.1, pp.32-39. ISSN 2007-8080.

Previous to determination of the pH effect in just buffer solutions or ammended with NaOCl on sclerotia of Phymatotrichopsis omnivora, in this work, sclerotia survival exposed during 14 days to an isolate of Trichoderma sp. in buffers solutions at pH 4, 5, 6, 8.2, and 10.4, and acetic acid solutions at 0, 25, 50, and 100 ppm was evaluated. Sclerotia survival was also evaluated in aqueous and buffer solutions ammended with 1000 ppm of Tilt (Propiconazole) during one minute up to three day exposure. Sclerotia survival in presence of Trichoderma sp. after 14 days was 90 and 10% at pH 6 and 8.2, respectively, but at pH 4, 5, and 10.4 sclerotia did not survive a single day. In the presence of Trichoderma sp. incubated 14 days at 0, 25, 50, and 100 ppm of acetic acid, sclerotia showed 100, 80, 40, and 0% survival, respectively. The time needed to kill 100% sclerotia diminished 864 and 216 times using 1000 ppm of Tilt at pH 4 and 5, respectively, with respect to the time needed to obtain the same effect at pH 7 (3 days). The pH had a determinant effect on survival of sclerotia of P. omnivora.

Palavras-chave : Soilborne plant pathogens; soil fungi.

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