Distribution and Occurrence of Vairimorpha plodiae (Opisthokonta: Microspora) in the Indian Meal Moth, Plodia interpunctella (Lepidoptera: Pyralidae) Populations: An Extensive Field Study

Abstract

The Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae) is one of the most important stored product pests. Fumigation plays a significant role in the management of insect pests in stored-products. However, the use of fumigants is problematic because of their effects on the environment and high costs. Entomopathogenic organisms are environmentally friendly control agents and suppress pest populations under natural conditions. In this study, distribution and occurrence of a microsporidian pathogen, Vairimorpha plodiae (Opisthokonta: Microspora) in the populations of P. interpunctella from 12 localities representing Turkey between 2019 and 2020 are presented for the first time by confirming its effectiveness on natural populations. The presence of the microsporidian pathogen was found in 11 of 12 (91.7%) populations. In total, 863 of 3,044 samples were infected by the pathogen. Infection mean was 28.4% for all populations. Our results showed that V. plodiae infection reached to a considerably high prevalence (88.77%) in P. interpunctella populations and varied from 5.1 to 88.7% between the populations. In addition, microsporidia infections have been identified throughout Turkey. We found that V. plodiae can infect all life stages of P. interpunctella. Totally, 623 (28.5%) of 2187 larvae, 14 (37.8%) of 37 pupae, 226 (27%) of 820 adults were found to be infected by the pathogen. There were considerable differences between the dead and living larvae. The microsporidian infection was found in 26 (11.6%) of 225 living larvae, whereas it was found in 595 (30.5%) of 1,952 dead larvae. These results confirm that the microsporidia pathogen has a high spreading potential in P. interpunctella populations and can be a natural biological suppression factor on pest populations.