Effects of surface type and distance traveled on the efficacy of a <i>Beauveria bassiana</i> (Hypocreales:Cordycipitaceae)-based biopesticide (Aprehend) for bed bug (Hemiptera: Cimicidae) control

The cryptic behavior that characterizes bed bugs (Cimex lectularius L.) makes them one of the most difficult indoor pests to control. Thus, the use of products with long residual efficacy is a key component of successful bed bug management. Aprehend is a biopesticide for bed bug control, whose active ingredient is the entomopathogenic fungus, Beauveria bassiana. This product shows promise for extended bed bug control against pyrethroid-resistant bed bugs, causing mortality days after contact with the treated surface. However, it is unclear how surface type and distance traveled by bed bugs over a treated surface impact efficacy. Therefore, we evaluated the efficacy of different Aprehend band widths applied to different substrates commonly encountered by bed bugs, looking specifically at average time to mortality and overall mortality. Our findings indicate that exposure to fresh applications of Aprehend resulted in high mortality when bed bugs traveled very short distances (1 cm) over some Aprehend-treated surfaces (vinyl tile and cotton jersey fabric), while exposure to other treated surfaces (unfinished pinewood and painted drywall) resulted in comparatively lower mortality even over longer distances (5 cm). Furthermore, we found that bed bugs crawling on cotton jersey fabric picked up a significantly higher number of spores compared to unfinished pinewood. These results indicate that applications of Aprehend as 5 cm (2 inches) bands according to label recommendations can be effective, although surface type is an important determinator of efficacy. This information will help guide pest management professionals in their use of B. bassiana for bed bug control.