Abstract
BackgroundMycosis on the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), infecting maize was observed in research farm of Regional Agricultural Research Station, Anakapalli from October 2019 to February 2020.Main bodyHigh relative humidity (94.87%), low temperature (24.11 °C), and high rainfall (376.1 mm) received during the month of September 2019 predisposed the larval instars for fungal infection and subsequent high relative humidity and low temperatures sustained the infection till February 2020. An entomopathogenic fungus (EPF) was isolated from the infected larval instars as per standard protocol on Sabouraud’s maltose yeast extract agar and characterized based on morphological and molecular analysis. The fungus was identified as Metarhizium (Nomuraea) rileyi based on ITS sequence homology and the strain was designated as AKP-Nr-1. The pathogenicity of M. rileyi AKP-Nr-1 on S. frugiperda was visualized, using a light and electron microscopy at the host-pathogen interface. Microscopic studies revealed that all the body parts of larval instars were completely overgrown by white mycelial threads of M. rileyi, except the head capsule, thoracic shield, setae, and crotchets. The cadavers of larval instars of S. frugiperda turned green on sporulation and mummified with progress in infection. In vitro pathogenicity tests revealed the potential of AKP-Nr-1 strain of M. rileyi in management of S. frugiperda.Short conclusionThe results indicated the potential of M. rileyi AKP-Nr-1 as biocontrol agent for management of the fall armyworm. This AKP-Nr-1 strain of M. rileyi needs further evaluation under field conditions to evaluate its efficacy against S. frugiperda and its effects on other hosts.
Highlights
Materials and methods The present study was carried out at the Regional Agricultural Research Station (RARS), Anakapalli (17° 40′48′′ N, 83° 01′ 12′′ E), Visakhapatnam, Andhra Pradesh, India, during 2019–2020 crop seasons
Isolation of entomopathogenic fungus (EPF) Larval instars of S. frugiperda infected with EPF were collected from the maize field in the research farm of Regional Agricultural Research Station (RARS), Anakapalli, during October 2019 and the pathogen was isolated on Sabouraud’s maltose yeast extract agar (SMYA) by standard protocol of Vimala et al (2002)
High infestation of Fall armyworm (FAW) was recorded from 2nd fortnight of October to December 1st fortnight with minimum temperatures of 19.63–24.39 °C and high relative humidity (RH) (90–98%)
Summary
FAW attack on maize has the potential to cause yield losses in a range from 8.3 to 20.6 million tons per annum, in the absence of any control measure. Prevalence, distribution, and mycosis of entomo-fungal pathogens were found influenced by weather parameters like temperature, rainfall, and humidity (Maurya et al 2013) Some of these fungi were isolated in pure form, evaluated and identified as potential biocontrol agents for pest management owing to their specificity and ease of multiplication. Among various EPF, Metarhizium (Nomuraea) rileyi (Farlow) Samson was reported to infect several lepidopteran pests and found highly effective against noctuid defoliators like Spodoptera litura Fabricius, Helicoverpa armigera (Hubner), Anticarsia gemmatalis (Hubner), and Trichoplusia ni Hubner (Keller and Zimmermann 1989) for their ecofriendly management. Pathogenicity tests were conducted to study the efficacy of the native strain of the fungus on FAW in maize
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
