Potential of Moroccan entomopathogenic nematodes for the control of the Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae)

Authors: MOKRINI, FOUAD - National Institute Of Agronomic Research Of Morocco (INRA); LAASLI, SALAH-EDDINE - Mohammed V University; BENSEDDIK, YOUSSEF - National Institute Of Agronomic Research Of Morocco (INRA); JOUTEI, ABDELMALEK - Ecole Nationale D’Agriculture De Meknes; BLENZAR, ABDELALI - Moulay Ismail University; LAKHAL, HICHAM - Delassus Group; SBAGHI, M - National Institute Of Agronomic Research Of Morocco (INRA); IMREN, MUSTAFA - Bolu Abant Izzet Baysal University; OZER, GOKSEL - Bolu Abant Izzet Baysal University; Paulitz, Timothy; LAHLALI, RACHID - Ecole Nationale D’Agriculture De Meknes; DABABAT, ABDELFATTAH - International Maize & Wheat Improvement Center (CIMMYT)

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2020
Publication Date: 11/5/2021
Citation: Mokrini, F., Laasli, S., Benseddik, Y., Joutei, A.B., Blenzar, A., Lakhal, H., Sbaghi, M., Imren, M., Ozer, G., Paulitz, T.C., Lahlali, R., Dababat, A.A. 2021. Potential of Moroccan entomopathogenic nematodes for the control of the Mediterranean fruit fly Ceratitis capitata Wiedemann (Diptera: Tephritidae). Scientific Reports. 10. Article 19204. https://doi.org/10.1038/s41598-020-76170-7.
DOI: https://doi.org/10.1038/s41598-020-76170-7

Interpretive Summary: This paper looks at the effectiveness of entomopathogenic nematodes (EPNs) collections from Morocco to control the Mediterranean fruit fly. This fruit fly is a major pest of fruit world wide. EPNs attack the larvae and pupae of the fruit fly in the soil, and vector a bacterium that kills the insects. An number of EPN strains, including Steinernema feltiae and Heterorhabditis bacteriophora were effective in an apricot bioassay.

Technical Abstract: The Mediterranean fruit fly (Medfly), Ceratitis capitata Wiedemann, is one of the most economically deleterious pests worldwide, affecting fruit production. Its control still relied heavily on chemical treatments, which are increasingly poorly appreciated for their negative effects on both human health and the environment. The use of entomopathogenic nematodes (EPNs) as potential biocontrol agents could be an effective alternative strategy to overcome or limit this bottleneck in the Medfly control. In this study, five EPN strains, isolated from different fields in Morocco, were evaluated for their effectiveness against the third-instar larvae and pupae of C. capitata under laboratory and glasshouse conditions. In laboratory assays, both Steinernema feltiae-SF-MOR9 and Heterorhabditis bacteriophora-HB-MOR7 strains showed significantly higher infectivity and penetration rates when compared to the other strains. Moreover, an apricot (Prunus armeniaca) assay was conducted in the soil to evaluate the ability of EPN strains to infect the third-instar larvae inside apricot fruits. S. feltiae-SF-MOR9 caused the highest larval mortality rate (80%) at 50 infective juveniles (IJs) cm-2. The effective mortality of C. capitata larvae was also observed at other EPN concentrations (10, 25, 100, and 150 IJs cm-2). Results underlined that both Steinernema strains (SF-MOR9 and SF-MOR10) were significantly effective in controlling C. capitata larvae with high mortality rate at 50 and 100 IJs cm-2, respectively. Based on the mortality rate the strain Heterorhabditis HB-MOR7 was more efficient to control of C. capitata pupae. Different soil textures and moisture levels resulted in a significant variation in EPN strains virulence against C. capitata. Sandy clay loam soils in combination with 50 IJs cm-² of S. feltiae (SF-MOR9 or SF-MOR10) caused a higher mortality rate of C. capitata larvae compared to clay and loamy sand textures. Furthermore, applying these EPN strains at 50-100 IJs cm-² in combination with 10-15% moisture level showed optimal results against C. capitata larvae. Therefore, it is concluded that Moroccan EPN strains of S. feltiae-SF-MOR9 and S. feltiae-SF-MOR10 could be used as a promising eco-friendly alternative for reliable control of C. capitata.