Evaluation of manuka honey on the microsporidian pathogen Vairimorpha (Nosema) adaliae and its host, the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae)

Abstract

Honey is known for its antibacterial and antifungal properties. Manuka honey was examined for its potential to manage the microsporidium Vairimorpha (Nosema) adaliae infecting Adalia bipunctata larvae. Development time for uninfected larvae fed aphids and water was 13.0 ± 0.2 days, which did not differ significantly from larvae fed aphids and manuka honey. Development of V. adaliae-infected larvae fed aphids and water was 16.3 ± 0.5 days, compared to 15.0 ± 0.2, 15.2 ± 0.3, and 15.6 ± 0.2 days for larvae fed aphids and 5 %, 10 %, or 15 % manuka honey, respectively. Development time was shorter for all honey treatments, but only those fed 5 % manuka differed significantly from the control. Control adults had 19.4 ± 3.0 spores/120 µm2, compared to 19.0 ± 2.0, 19.1 ± 2.1, and 14.3 ± 2.2, for adults provided with 5 %, 10 %, and 15 % honey, respectively. Although spore loads did not differ significantly (p > 0.05), lighter infections were observed in the group fed 15 % manuka.