Revista mexicana de fitopatología
Print version ISSN 0185-3309
SAMANIEGO-GAXIOLA, José Alfredo. Effect of pH on sclerotia survival of Phymatotrichopsis omnivora (Dugg.) Hennebert exposed to buffer solutions, acetic acid, and to NaOCl. Rev. mex. fitopatol [online]. 2008, vol.26, n.2, pp. 177-179. ISSN 0185-3309.
Phymatotrichopsis omnivorous is a limiting factor for the exploitation of several agricultural crops in Mexico and the United States, and there are not practical control methods. Since the fungus does not cause evident damage to plants in acid soils, a study was undertaken on the effect of pH on sclerotia survival in: buffers solutions (pH 4, 5, 6, 7 and 7.8); buffers solutions ammended with 100, 500, 1000, and 3000 ppm of NaOCl; solutions at 0, 25, 50, and 100 ppm of acetic acid; and in flooded or without flooded soil ammended with acetic acid at 0, 2500, 5000, 10000, 25000, and 50000 ppm. Sclerotia were incubated in the solutions or soils from one day up to three weeks at 28°C, with the exception in NaOCl solutions, where incubation lasted four hours. Sclerotia did not survive after one week in buffer solutions at pH 4 and 5, while at pH 6, 7, and 7.8 they survived 100, 80, and 1% after three weeks, respectively. Sclerotia were 100% viable in the solutions or soils ammended with acetic acid. A 20% of sclerotia survived in NaOCl solution at 1000 ppm and pH 6.
Keywords : Soilborne fungi; fungistasis; ecology of micro-fungi.