Evaluation of Pachycrepoideus vindemiae and Muscidifurax raptor (Hymenoptera: Pteromalidae) as biological control agents of Piophila casei (Diptera: Piophilidae) in ham production facilities

Abstract

Ham products play a fundamental role in the Italian economy, and attention to the problems of this sector is essential. The products of this sector can be attacked by parasites, which can cause direct and indirect damage. Piophila casei (L.) (Diptera: Piophilidae) a cheese and meat parasite, is currently responsible for hygiene problems in ham factories. The trophic activity of this pest on the products causes serious direct damage and it is a vector of various bacteria, including Clostridium botulinum. Another risk is human ingestion of the larvae, which are resistant to gastric juices action, potentially causing intestinal myiasis. Insecticide use of any type is not allowed in aging rooms, so biological control can represent a potential alternative. In this study, we investigate quality parameters such as successful rate of parasitism (SP), degree of parasitism (DP), sex-ratio (SR), life-span (LS), and emergence rates (ER) of 2 pupal parasitoids of Diptera: Pachycrepoideus vindemiae (Rondani) (Hymenoptera: Pteromalidae), currently the only known pupal parasitoid of P. casei, and Muscidifurax raptor (Girault and Sanders) (Hymenoptera: Pteromalidae). Our research confirmed P. vindemiae efficacy to parasitize P. casei and reported, for the first time, M. raptor as a pupal parasitoid of this Piophilidae. ER for both parasitoids were low, thus affecting the DP and SP estimations. This could be explained by the feeding behavior of the parasitoid host. The strongly female-biased SR for P. vindemiae supported previous studies. LS results in our experiment are crucial for determining the timing of release.