NEW RECORDS OF <I>POCHONIA CHLAMYDOSPORIA</I> FROM MEXICO: ISOLATION, ROOT COLONIZATION AND PARASITISM OF <I>NACOBBUS ABERRANS</I> EGGS
Keywords:false root-knot nematode, Los Tuxtlas, microbiological control, nematophagous fungi, plant-parasitic nematodes
AbstractFranco-Navarro, F., K. Vilchis-Martinez, and J. Miranda-Damian. 2008. New records of Pochonia chlamydosporia from Mexico: Isolation, Root colonization and Parasitism of Nacobbus aberrans eggs. Nematropica 39:133-142. One hundred and six soil samples were taken from the buffer zone of the Biosphere Reserve of "Los Tuxtlas", Veracruz, Mexico, and examined for the presence of native isolates of the fungus Pochonia chlamydosporia. Samples were collected from locations with different land uses (i.e. natural forest, secondary forest, pasture fields and maize fields) and were processed using a selective medium to isolate the fungus. Two varieties of the fungus (alone or in combination), were found in a total of 30 soil samples: P. c. var. chlamydosporia was present in 25 samples and P. chlamydosporia var. catenulata in 10 of the samples. Six isolates were present in pasture fields, 4 in maize fields, 13 in secondary forest and 12 in natural forest. All isolates were tested on maize for their ability to colonize roots, and to parasitize eggs of the nematode Nacobbus aberrans. There were highly significant differences in the proportion of eggs parasitized by the different isolates (Tukey, α < 0.01). Eight isolates parasitized >80% of the eggs, 16 parasitized between 70-80%, and 11 parasitized <70%. Root colonization ranged from 75-100%: 12 isolates colonized all root segments, 14 colonized 90-99% of them, six colonized 80-89% and three colonized only 75%. This is the first record of P. c. var. catenulata being present in Mexican soils and the first record of P. chlamydosporia in natural habitats-non-disturbed soils-from Mexico.