Trichoderma spp. promote root growth and high populations of Meloidogyne enterolobii on tomato crop

Abstract

Summary Meloidogyne enterolobii is an emerging pathogen in Brazil, considered highly destructive to tomato. Due to the lack of cultivars resistant to this nematode, the objective of this work was to evaluate the effect of Trichoderma spp. strains on the promotion of tomato growth and biological control of M. enterolobii populations. The use of eight strains from the CENARGEN collection and three formulated products at a concentration of 1.43 × 106 conidia ml−1 significantly increased the fresh weight of roots compared to control plants inoculated only with nematodes. These Trichoderma strains, except CEN316, also promoted a significant increase in the number of nematodes and in the reproduction factor (RF). With the increase of spore concentration (1 × 108 conidia ml−1) in the second assay, the inoculation of nematode or fungi plus nematode promoted an increase in the fresh weight of roots, except in treatments CEN162, CEN287, UFT 201, and CEN287 + nematodes, which maintained the fresh weight of roots equal to the control without nematodes. None of the spore concentrations (1.43 × 106 and 1 × 108 ml−1) of different Trichoderma spp. strains influenced the plant height (45 and 90 days after nematode inoculation) or the dry plant weight 90 and 110 days after nematode inoculation, respectively. However, there was a positive and significant correlation between RF and fresh root weight, eggs (g root)−1 and total eggs, in the two doses. Furthermore, the Trichoderma spp. strains did not result in control of M. enterolobii under glasshouse conditions after a complete life cycle of the tomato plant: high nematode infection was observed in both doses of the fungi, including in treatments with the commercial formulations.