Effects of Chemical Insecticide Residues and Household Surface Type on a Beauveria bassiana-Based Biopesticide (Aprehend®) for Bed Bug Management.

The biopesticide Aprehend, containing spores of the entomopathogenic fungus Beauveria bassiana, is a biological control agent for the management of the common bed bug (Cimex lectularius L.) (Hemiptera: Cimicidae). The spores are applied in strategically placed barriers, which bed bugs walk across as they search for a bloodmeal. Application of chemical insecticides by the general public and professional pest managers is common, which means that Aprehend may be sprayed on existing insecticide residues. We evaluated the effect of chemical residues, of 22 different chemical insecticides on different household surface types. We found that residues from 12 chemical pesticides significantly reduced spore viability measured 5 weeks after application in comparison to the control. However, efficacy of Aprehend, as measured by bed bug mortality and mean survival time after exposure to sprayed surfaces, seven weeks after application was not impacted detrimentally. Furthermore, in some cases, efficacy of old chemical residues was enhanced by the combination of chemical and Aprehend seven weeks after application. Surface type also played a role in the relative efficacy of all products and combinations, particularly as the residues aged.

Persistence and Lethality of a Fungal Biopesticide (Aprehend) Applied to Insecticide-impregnated and Encasement-type Box Spring Covers for Bed Bug Management.

The newly developed fungal biopesticide Aprehend, containing spores of Beauveria bassiana, is the first biological control agent to be incorporated into management programs to control the common bed bug (Cimex lectularius L.) (Hemiptera: Cimicidae). Aprehend is sprayed as barriers where bed bugs are likely to walk and pick up spores as they search for a bloodmeal. A key application target for Aprehend is the box spring, which may be covered by encasement-type or insecticide-impregnated covers. Since some insecticides can reduce the persistence of fungal spores, we tested the efficacy and spore germination percentages of Aprehend when applied to the two types of box spring covers. We found that spore germination was about 11% lower on the permethrin-impregnated ActiveGuard cover than on the encasement-type AllerEase cover. However, bed bugs exposed for 15 min to Aprehend on the two box spring covers suffered similarly high levels of mortality irrespective of the cover material. Thus, there was no inhibitory or additive effect of the ActiveGuard cover on bed bug mortality. Lastly, overall mortality was higher if bed bugs were exposed to Aprehend-treated ActiveGuard than the ActiveGuard cover alone. Our findings indicate that if pest managers are using ActiveGuard covers in combination with Aprehend, best practice would be to use ActiveGuard on mattresses and apply Aprehend directly to the box spring or to a box spring covered by an encasement-type cover.

Susceptibility of insecticide-resistant bed bugs (Cimex lectularius) to infection by fungal biopesticide.

BACKGROUND: Bed bugs are a public health concern, and their incidence is increasing worldwide. Bed bug infestations are notoriously difficult to eradicate, further exacerbated by widespread resistance to pyrethroid and neonicotinoid insecticides. This study evaluated the efficacy of the newly developed fungal biopesticide Aprehend™, containing Beauveria bassiana, against insecticide-resistant bed bugs. RESULTS: Overall mortality for the Harold Harlan (insecticide-susceptible) strain was high (98-100%) following exposure to Aprehend™ or Suspend SC (deltamethrin). The mean survival times (MSTs) for Harold Harlan bed bugs were 5.1 days for Aprehend™ and 4.8 and 3.0 days for the low and high concentrations of Suspend SC respectively. All three strains of pyrethroid-resistant bed bugs were susceptible to infection by B. bassiana, resulting in MSTs of <6 days (median = 4 days) and >94% overall mortality. Conversely, mortality of the three insecticide-resistant strains after exposure to Suspend SC was only 16-40%. CONCLUSION: These results demonstrate that Aprehend™ is equally effective against insecticide-susceptible and insecticide-resistant bed bugs and could provide pest control operators with a promising new tool for control of bed bugs and insecticide resistance management. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.