Indian Journal of Entomology Online published Ref. No. e22560 DoI. No.: 10.55446/IJE.2022.801 COMPATIBILITY OF ENTOMOPATHOGENIC FUNGUS METARHIZIUM RILEYI WITH BIORATIONALS Kajal Bharti, Neelam joshi*, saijal Khosla aNd raBiNder Kaur 1 Department of Microbiology; 1 Department of Entomology, Punjab Agricultural University, Ludhiana 141004, Punjab, India *Email: neelamjoshi_01@pau.edu (corresponding author): ORCID ID 0000-0002-4159-5691 ABSTRACT In this study, Metarhizium rileyi isolates (M. rileyi NIPHM, M. rileyi MTCC 4254 and M. rileyi MTCC 10395) were evaluated for their compatibility with other entomopathogenic fungi viz. Metarhizium anisopliae NBAIR (Ma-35), commercial formulation of M. anisopliae, M. anisopliae (Local), Beauveria bassiana ITCC 7126, B. bassiana (Local) and commercial formulation of Verticillium lecanii and neem based formulations- (azadirachtin 0.03%EC) and (azadirachtin 0.15%EC) along with synthetic insecticide spinetoram 11.7%SC. Neem-based formulations viz., azadirachtin 0.03% EC 1.5 ml/ l and 0.15%EC 5 ml/ l reduced M. rileyi MTCC 4254 growth by 44.77% and 53.73% over control, respectively; M. rileyi MTCC 4254 was more compatible with M. anisopliae NBAIR (Ma-35) and commercial formulation of M. anisopliae with less reduction in growth (24.3% and 24.9%, respectively); but it was least compatible with commercial formulation of V. lecanii. M. rileyi MTCC 4254 recorded 71.64% reduction with spinetoram 11.7% SC (0.4 ml/ l). Thus, M. rileyi was compatible with M. anisopliae NBAIR (Ma-35), M. anisopliae followed by azadirachtin 0.03% EC, and these could be used as components in IPM. Key words: Metarhizium rileyi, M. anisopliae, Beauveria bassiana, Verticillium lecanii, azadirachtin, spinetoram, compatibility, reduction in growth, IPM Entomopathogens are microbial control agents used for crop pest management. Entomopathogenic fungi (EPF) like Metarhizium anisopliae, Beauveria bassiana, Verticillium lecanii and Metarhizium rileyi are widely used against pest in agriculture felds and greenhouses. These are ecofriendly and have an important role in plant protection for sustainable IPM (Grewal and Joshi, 2021). Synthetic pesticides traditionally used have negative effects, and efforts have been made to reduce their use. Metarhizium rileyi (Farlow) Kepler, Rehner and Humber, formerly known as Nomuraea rileyi (Kepler et al., 2014), is a fungus with a specifc host range that is used as a biocontrol agent for the management of lepidopteran pests. These secrete secondary metabolites that act as immunosuppressive compounds which lead to fungal infection (Constanza et al., 2019). Botanicals can also be used as an alternative because they pose little risk to humans and they can be readily combined with many other bioagents (Mohan et al., 2007). Azadirachtin is less harmful to the environment and prevents development of insect resistance (Isman, 2006). In IPM the compatibility of such fungi with botanicals and pesticides is very important (Neves et al., 2001) and can improve effectiveness with less pollution risks by reducing the amount of pesticides used (Usha et al., 2014). Compatibility studies on these are important to deploy such biopesticides and biocontrol agents (Rashid et al., 2010). Therefore, compatibility of entomopathogenic fungi with botanicals/ other microbials is necessary (Sahayaraj et al., 2011). This study assesses the compatibility of M. rileyi with neem formulations, insecticides and other entomopathogenic fungi. MATERIALS AND METHODS Two M. rileyi isolates, viz. MTCC 10395 and MTCC 4254, were procured from the Institute of Microbial Technology (IMTECH), Chandigarh, India, and one isolate, M. rileyi NIPHM, was procured from the National Institute of Plant Health Management, Hyderabad, India. These isolates were grown and maintained on Sabouraud maltose agar with yeast extract (SMAY) (mycological peptone 1%, maltose 4%, agar 2%, yeast extract 1% and chloramphenicol 0.5%), and refrigerated till further use. Compatibility study of M. rileyi with azadirachtin and insecticide was carried out using the poison food technique with some modifcations (Reddy et al., 2021). Azadirachtin 0.03%EC (@ 1.5 ml/ l, @ 2.5 ml/ l), azadirachtin 0.15% EC (@ 5 ml/ l, @ 10 ml/ l) and spinetoram 11.7%SC (@ 0.2 ml/ l, @ 0.4 ml/ l) were added individually to