Protecting the hive: Enhancing biocontrol of Aethina tumida through entomopathogenic nematode protection from UV radiation and desiccation

The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is an economically important pest of honeybee colonies in the United States. Current control methods predominantly rely on chemical insecticides, which raise concerns about the development of resistance by the pest, and negative environmental impacts due to pesticide contamination. Entomopathogenic nematodes (EPNs) offer a sustainable alternative; however, their efficacy is often compromised by abiotic stressors such as ultraviolet (UV) radiation and desiccation. The current study assessed the effect of UV radiation on the efficacy of four EPN species: Steinernema carpocapsae (All), S. riobrave (355), Heterorhabditis floridensis (K22), and H. georgiana (Kesha) against A. tumida larvae in conjunction with three UV-protective materials: 2% Barricade, organic mulch, and landscape fabric. This experiment was conducted under laboratory conditions, with A. tumida larval mortality quantified at 7- and 14-days post-treatment (dpi). Preliminary results revealed that S. riobrave when applied with 2% Barricade or fabric, caused the highest larval mortalities at 7 dpi, which were 55% for barricade and 60% when combined with fabric. Steinernema carpocapsae exhibited moderate efficacy across all materials, while H. floridensis and H. georgiana demonstrated limited effectiveness, with mortality not exceeding 30% in any treatment. These initial results suggest that both UV protecting materials type and EPN species substantially influence the suppression of A. tumida larvae, with S. riobrave emerging as the most promising candidate. However, further replications and completion of 14 dpi assessments are necessary to confirm these trends. Furthermore, field study is necessary to validate findings under natural conditions.