Application of Beauveria bassiana and Neoseiulus barkeri for improved control of Frankliniella occidentalis in greenhouse cucumber

To improve sustainable control of the western flower thrips, Frankliniella occidentalis Pergande, a single application of the entomopathogenic fungus Beauveria bassiana followed by a release of the predatory mite Neoseiulus barkeri Hughes against F. occidentalis were evaluated on greenhouse cucumbers in 2013 and 2015. A single application of B. bassiana significantly reduced F. occidentalis by 70% (2013) and 64% (2015) two weeks after spraying. N. barkeri, which was released two weeks after spraying, further suppressed F. occidentalis populations which remained low for the remainder of the trial; numbers were reduced by 72 and 75% in 2013 and 2015, respectively, five weeks after the predator was released. These results suggest that an application of B. bassiana followed by N. barkeri applied two weeks later is a viable approach for controlling F. occidentalis.