Biocontrol of tomato psyllid (Bactericera cockerelli) using individual application of Trichoderma atroviride or Engytatus nicotianae and their combination

Abstract

The management of tomato potato psyllid (TPP), Bactericera cockerelli, is problematic because of pesticide resistance and environmental issues. Engytatus nicotianae has shown promising predatory effect on TPP in glasshouses. Trichoderma isolates have been reported to alter the behaviour of pests or their enemies by modifying plant defence metabolites such as volatile organic compounds (VOCs). We investigated the individual and combined efficacy of Trichoderma atroviride and E. nicotianae against TPP abundance and across different developmental stages (eggs, nymphs, adults) and the number of infested leaves in glasshouse grown tomatoes. Plant VOC emissions were also investigated under the different treatments. Across all measured TPP stages the treatments (E. nicotianae alone, T. atroviride alone, and T. atroviride + E. nicotianae) significantly reduced mean TPP counts relative to the control but there were no significant differences in VOC emissions among the treatments. Trichoderma atroviride alone was less effective than E. nicotianae alone or its combination with Trichoderma atroviride to suppress TPP populations. The combined use of T. atroviride + E. nicotianae did not show significant advantages over the use of E. nicotianae alone in supressing TPP suggesting the combined use may need to be assessed for other advantages of Trichoderma to crop including growth promotion or pathogen defence.