Native Isolates of Entomopathogenic Fungi, Beauveria bassiana and Metarhizium anisopliae, as Potential Biological Control Agents Against Pistachio Stink Bug, Acrosternum arabicum (Hemiptera: Pentatomidae)

Abbas Esmaeili Sardary (PhD Student)^1,2 , Fateme Ranjbara (PhD)², Mandana Motesaddi Zarandi (BSc)², Yazdan Nasiri (BSc)², Sepehr Salari Rafsanjanipoor (BSc)², Maryam Rashki (PhD)^3*,  M. Amin Jalali (PhD)^1,2

¹ Pistachio Safety Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran

² Department of Crop Protection, College of Agriculture, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran

³ Department of Biodiversity, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran

Received: 10.06.2024  Accepted: 15.09.2024

Abstract

Background: Entomopathogens such as Metarhizium anisopliae and Beauvaria bassiana have undergone extensive study for their pathogenic impact on various insects and have been globally employed as myco-biocontrol agents for the ecological regulation of agricultural pests.

Materials and Methods: This study assesses the biocontrol efficacy of three isolates of B. bassiana (GHA, DEBI008, and Z1) and one isolate of M. anisopliae against Acrosternum arabicum, a primary pest of pistachio nuts in Iran, and explores the impact of humidity on their virulence under controlled laboratory conditions (25±2 ºC, 75-95% RH, and a 16L:8D photoperiod).

Results: The research confirmed the susceptibility of A. arabicum to all four fungal isolates, with higher humidity levels intensifying their virulence. Specifically, B. bassiana isolates DEBI008 and Z1 displayed the shortest median lethal times (LT50) at 75% relative humidity, inducing 100% mortality within 16 days. In contrast, M. anisopliae exhibited a heightened response to humidity, leading to a rapid 50% mortality rate at 95% relative humidity within 4 days. While none of the isolates achieved complete mortality at a low concentration of 1 × 10⁵ conidia/mL, the findings suggest promising avenues for future field investigations.

Conclusions: This study underscores the potential of B. bassiana and M. anisopliae as effective biological control agents, potentially integrating them into sustainable pest management strategies for pistachio orchards. Further field trials are recommended to validate laboratory results and promote the adoption of these biocontrol agents in Integrated Pest Management (IPM) programs.

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