Occurrence and Distribution of Entomopathogenic Fungi in Cultivated Soil and Its Efficacy Against<em> Helicoverpa armigera </em>(Hubner) (Lepidoptera: Noctuidae) Under Laboratory Conditions

Annually, global crop harvest significantly declines due to various pest attacks. Their effective management is crucial for sustainable agricultural productivity. Native entomopathogenic fungi (EPF) have been recognized as the most promising microbiological control agents against these pests. The present study aimed to isolate locally occurring entomopathogenic fungi and assess their efficacy against the serious noctuid pest, H. armigera, under laboratory conditions. EPF was explored in cultivated soil from crops of two distinct agro-ecological zones (plains and foothills) in Khyber Pakhtunkhwa province, Pakistan. Using the Galleria baiting technique, fungal isolates were recovered from collected soil samples. Upon identification, these isolates belonged to 4 different EPF species, viz., Nomuraea rileyi, Aspergillus parasiticus, A. niger, and A. flavus. Results revealed that soils from the foothills exhibited a comparatively higher percentage distribution of isolates than those from the plains. Aspergillus niger was the most abundant fungal species in various localities and crops. The pathogenicity of four isolated species was assessed against H. armigera at three concentrations (1x106, 1x107 and 1x108 conidia/mL). Results revealed that the H. armigera larvae were found to be susceptible to all tested EPF species, particularly at high concentration levels. M. rileyi was the most effective, causing the highest percent mortality and exhibiting the lowest percentage of pupal recovery and adult emergence, followed by Aspergillus species. Probit analysis showed that M. rileyi was highly virulent, with the lowest LC50 and LT50 values. This study reveals the potential of M. rileyi to serve as an effective biocontrol agent in integrated pest management strategies against H. armigera, and as a promising candidate for bio-pesticide product development. The use of EPF agents will ensure the production of healthier organic crops by eliminating insecticide residue and resistance problems.