D3001: Manipulating the UV landscape to improve biological control by entomopathogens

Lygus lineolaris is key pest of strawberry that is notoriously difficult to manage, especially under new protected culture systems where control options may be limited. In addition, effective and practical biocontrol options are greatly needed. This study employed lab and field experiments to determine how UV-selective plastics can be used to improve efficacy of the fungal biocontrol agent Beauveria bassiana against L. lineolaris on low tunnel strawberry. We evaluated the effect of different plastics and other covering ranging in UVB transmissibility on the survival of Beauveria bassiana in cultures and pathogenicity against L. lineolaris when sprayed as the product ‘Mycotrol’ in the lab under artificial UVB. In the field, ‘Mycotrol’ and the conventional insecticide ‘Assail’ was applied on strawberry under low tunnel plastics that ranged in UVB transmissibility. We evaluated the survival of sentinel L. lineolaris adults, abundance of naturally occurring L. lineolaris, and damage symptoms of fruit and yield of these treatments compared to a control. Results indicated that applying B. bassiana under UVB-blocking plastics will likely improve spore viability and infectivity against L. lineolaris, but this may not translate into population-level suppression of L. lineolaris and reduced yield loss, especially compared to conventional management practices. However, both biocontrol and conventional products performed better under low tunnels compared to the open-field, indicating that plastic selection is a useful IPM tool for managing L. lineolaris on low tunnel strawberry.