In Vitro Assessment of Organic and Residual Fractions of Nematicidal Culture Filtrates from Thirteen Tropical Trichoderma Strains and Metabolic Profiles of Most-Active.

The nematicidal properties of Trichoderma species have potential for developing safer biocontrol agents. In the present study, 13 native Trichoderma strains from T. citrinoviride , T. ghanense (2 strains), T. harzianum (4), T . koningiopsis , T. simmonsii , and T. virens (4) with nematicidal activity were selected and cultured in potato dextrose broth to obtain a culture filtrate (CF) for each. Each CF was partitioned with ethyl acetate to obtain organic (EA) and residual filtrate (RF) fractions, which were then tested on second-stage juveniles (J2s) of the nematodes Meloidogyne javanica and M. incognita in a microdilution assay. The most lethal strains were T. harzianum Th43-14, T. koningiopsis Th41-11, T. ghanense Th02-04, and T. virens Th32-09, which caused 51-100% mortality (%M) of J2s of both nematodes, mainly due to their RF fractions. Liquid chromatography-diode array detector-electrospray-high resolution mass spectrometry analysis of the most-active fractions revealed sesquiterpene and polyketide-like metabolites produced by the four active strains. These native Trichoderma strains have a high potential to develop safer natural products for the biocontrol of Meloidogyne species.