Pochonia chlamydosporia Is the Most Prevalent Fungal Species Responsible for Meloidogyne Suppression in Sustainable Vegetable Production Systems

Abstract

The fluctuations in Meloidogyne densities and fungal egg parasitism were determined from February 2015 to July 2016 in four vegetable production sites conducted under organic production and two sides conducted under integrated standards. At each site, the soil nematode densities at transplanting and at the end of the crops, the galling index, the number of eggs in roots, and the percentage of fungal egg parasitism were determined, and the fungal species were identified. In addition, two pot experiments were conducted with soil taken from each site in February 2015 and 2016 to assess the fungal egg parasitism comparing non-sterile and sterile soil from each site. In field conditions, the nematode population densities in the soil decreased along the crop rotations. The maximum number of eggs per plant was recorded in the spring–summer crops. Egg parasitism ranged from 11.2 to 55% in the organic sites and from 0.8 to 16.5% in the integrated production sites. Pochonia chlamydosporia was the only fungal species isolated in five of the six sites. In both pot experiments, the number of eggs per plant was lower in non-sterile than in sterile soils, except for the M10.45 site, where fungal egg parasites were not recovered. P. chlamydosporia was the only fungal species isolated, ranging between 11 and 74%. Therefore, P. chlamidosporia was the most prevalent fungal species related to Meloidogyne suppression.