Monitoring of Trichoderma species in agricultural soil in response to application of biopreparations

•Application of T. atroviride/T. harzianum as biopreparations in lettuce cultivation.•Development of molecular markers for T. atroviride and T. harzianum identification.•Counting of Trichoderma spp. colonies in soil samples over time.•Identification of strains collected before and after biopreparations application.•Monitoring of Trichoderma population levels in soil over time with multiplex-PCR.