Survival of Root-Knot nematodes and their egg-parasitic fungus Pochonia chlamydosporia (Goddard) on weed roots

Abstract

Background: Root-knot nematodes is a major pest and difficult to control in vegetable crops worldwide. Pochonia chlamydosporia is an egg-parasitic fungus which attracts attention as a control agent of root-knot nematodes. Weeds serve as potential hosts for both root-knot nematodes and P. chlamydosporia. The objectives of this study was to assess several weed species as hosts of root-knot nematodes and P. chlamydosporia and assess the impact of fungicide foliar treatments on P. chlamydosporia colonies in roots. Methodology: Pot experiments were conducted to study research objectives. Tomato, black nightshade, common lambsquarter and common wild oat were assessed as hosts for root-knot nematodes and P. chlamydosporia. Also, thiophanate-methyl (systemic fungicide) and mancozeb (non-systemic fungicide) were foliarly sprayed to tomato plants already colonized with root-knot nematodes and P. chlamydosporia. Results: Root-knot nematodes and P. chlamydosporia successfully colonized roots of species tested. No significant differences were observed between treatments. P. chlamydosporia colonized successfully tomato roots although applied in low concentration of 1670 spores/ml. Colonization of roots by the fungus was observed as early as seven days after inoculation. No negative impact on P. chlamydosporia colonies in tomato roots sprayed with a fungicide, were observed. Conclusions: Root-knot nematodes can survive in roots of a wide range of plant species, either crops or weeds. This is very important particularly in fallow periods. P. chlamydosporia can be integrated in nematode control schemes and in combination with foliar fungicides in presence of wilt diseases in roots.

Bionomics and the role of antinemic metabolites of the nematophagous fungus, Pochonia chlamydosporia in suppressing phytonematodes - A Comprehensive Review

“…But in the native isolate colonization and recovery from the soil was higher under tunnel house on tomato (Sorribas et al, 2003). P. chlamydosporia was able to colonize weeds as well as cultivated crops (Bouchagier 2018). P. chlamydosporia root colonization caused the metabolic alterations in M. javanica roots, with a particular emphasis on production of phenolic compounds and flavonoids (de Souza Gouveia et al, 2022), and altered the expression of genes related to the defence system.…”