Infection and reinfection of Stomoxys calcitrans larvae (Diptera: Muscidae) by entomopathogenic nematodes in different times of exposure.

Américo De Castro Monteiro Sobrinho,Luís Carlos De Souza Rodrigues Leal,Graziele Calixto Souza,João Luiz Lopes Monteiro Neto,Melissa Carvalho Machado Do Couto Chambarelli,Avelino José Bittencourt,Isadora Luiza Alves Costa

doi:10.1590/s1984-29612021069

Américo De Castro Monteiro Sobrinho, Luís Carlos De Souza Rodrigues Leal + Show 5 more

Open Access

https://doi.org/10.1590/s1984-29612021069

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Abstract

Stomoxys calcitrans is a hematophagous dipteran. Several agents are used in biological control, including entomopathogenic nematodes (EPNs). Bioassay I involved an evaluation of the effect of Heterorhabditis bacteriophora HP88 and Heterorhabditis baujardi LPP7 on S. calcitrans larvae in different periods of exposure. Groups of 10 larvae were placed in Petri dishes and 200 EPNs/larva were added, which were divided into groups according to the exposure times of 2, 4, 6, 12, 24 and 48 hours. The purpose of Bioassay II was to evaluate the efficacy of the EPNs in infecting S. calcitrans larvae when they were isolated from stable fly larvae in Bioassay I. Groups of 10 larvae were placed in Petri dishes and 200 EPNs/larva were added. In bioassay I, H. bacteriophora caused mortality rates of 51.7, 83.3 and 91.7% in 12, 24 and 48 hours, respectively, while H. baujardi caused mortality rates of 9.3 (12h), 35 (24h) and 35% (48h). In Bioassay II, H. bacteriophora and H. baujardi resulted in mortality rates of 35% and 25%, respectively. It was concluded that the longest exposure times presented the highest larval mortality and that EPNs isolated from S. calcitrans are not efficient in controlling the larvae fly.

Highlights

Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) is a hematophagous dipteran commonly known as the stable fly, which can parasitize several animal species and may affect humans
The objectives of the present study was to evaluate the efficacy of Heterorhabditis bacteriophora (HP88) (Nematoda: Heterorhabditidae) and H. baujardi (LPP7) (Nematoda: Heterorhabditidae) infection on S. calcitrans larvae in different periods of exposure; and evaluate the efficacy of H. bacteriophora HP88 and H. baujardi LPP7, which were isolated from larvae of S. calcitrans on third instar larvae of the stable fly and to verify if S. calcitrans larvae would be efficient for nematodes multiplication
Infection of Stomoxys calcitrans larvae by entomopathogenic nematodes (EPNs) in different periods of exposure An analysis of the data indicated that the effect of the EPNs varied significantly as a function of exposure times

Summary

Introduction

Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae) is a hematophagous dipteran commonly known as the stable fly, which can parasitize several animal species and may affect humans. The duration of the life cycle of S. calcitrans depends directly on the environment and climate of the region (Bittencourt, 2012) Parasitism by this fly is detrimental to cattle in Brazil and around the world. The action of this fly causes annual economic losses estimated at 2.2 billion dollars in the United States (Taylor et al, 2012), and 335.5 million dollars in Brazil (Grisi et al, 2014). The latter figure does not take into account the impact of recent outbreaks reported in some regions of Brazil (Dominghetti et al, 2015). The nematodes of genus Heterorhabditis are used in the control of arthropods, including dipterans, around the world (Dolinski et al, 2012; Aatif et al, 2019; Bream et al, 2018; Mahmoud et al, 2007), in Brazil there are studies that show the efficiency of these EPNs in the control of S. calcitrans (Leal et al, 2017; Monteiro et al, 2016)

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