A reproducible infection protocol for entomopathogenic nematodes in the natural host Plodia interpunctella larvae

Entomopathogenic nematodes (EPNs) are important for the biological control of insect pests. At the same time, EPNs are excellent research tools for understanding the molecular and functional bases of the insect defense against parasitic nematode infection. Implementing insect models and natural hosts forms an important strategy for characterizing EPN virulence factors and insect anti-nematode immune responses. The Indian meal moth Plodia interpunctella is a world-wide insect pest of stored-products and processed food commodities. This insect species is also commonly infected by EPNs, and therefore, it can be used as a natural host to determine how insect pests interact with EPNs during infection. Obtaining this information is critical because it will allow agricultural practitioners to design improved EPN management tactics in the field. Here we describe a protocol for infecting P. interpunctella larvae with the EPNs Steinernema carpocapsae and S. hermaphroditum. The method is outlined below:•Third instar P. interpunctella larvae are infected with infective juveniles of either S. carpocapsae or S. hermaphroditum. Uninfected control larvae are exposed to sterile water only.•Insect survival is recorded at regular intervals.•Survival curves are constructed and results are statistically analyzed to compare the P. interpunctella larval mortality against the EPNs.