Exploring entomopathogenic fungi from South Sumatra (Indonesia) soil and their pathogenicity against a new invasive maize pest, Spodoptera frugiperda

Abstract

Abstract. Herlinda S, Octariati N, Suwandi S, Hasbi. 2020. Exploring entomopathogenic fungi from South Sumatra (Indonesia) soil and their pathogenicity against a new invasive maize pest, Spodoptera frugiperda. Biodiversitas 21: 2955-2965. Fall armyworm (Spodoptera frugiperda) is a new invasive maize pest in Indonesia that can cause maize yield losses of 18 million tons/year. To overcome the pest, local-specific entomopathogenic fungi are needed. This study aimed to explore entomopathogenic fungi from soil in South Sumatra and to determine their pathogenicity against S. frugiperda larvae. The fungi exploration was carried out in the lowlands and highlands of South Sumatra and the pathogenicity of obtained isolates were tested against the third instar larvae. The entomopathogenic fungi found were Metarhizium spp. and were successfully isolated as many as 14 isolates. All of the isolates were pathogenic to S. frugiperda larvae (70.67−78.67% mortality), the most pathogenic caused 78.67% mortality and significantly suppressed the emergence of adults up to 81.2%. Unhealthy larvae had a dry, shrunken, shrinking, odorless body, and its integument was covered in mycelia and conidia like yellowish-white powdery mixed with dark green. The unhealthy pupae and adults were in the abnormal and malformation shape. The abnormal pupae were shorter in size, bent, the to-be wings got wrinkled, and darker color, while the unhealthy adults had folded wings and were unable to fly. The two most pathogenic isolates were found from the lowland (PirOI) and highland (CasPsPGA) soil of South Sumatra. In conclusion, both of these isolates had the potential to be developed into local-specific mycoinsecticides to control pest insects in the highlands and/or lowlands in Indonesia.

The endophytic fungi from South Sumatra (Indonesia) and their pathogenecity against the new invasive fall armyworm, Spodoptera frugiperda

“…S. frugiperda was then taken to the laboratory to be maintained and mass-reared. The insect mass rearing modified the method of Herlinda et al (2020b). In the laboratory, the S. frugiperda larvae were reared individually in a porous plastic cup (Ø 6.5 cm, height 4.6 cm).…”

“…To measure the percentage of foliar damage caused by the larvae of S. frugiperda, the bioleaf application by Machado et al (2016) was used. Each day the dead larvae were recorded and carried out for 12 days based on the previous studies by Herlinda et al (2020b) and the dead larvae were grown in the agar-water medium to prove infection by the endophytic fungus. The number of larvae becoming pupae and adults that emerged was also counted.…”

“…Maize in Indonesia is currently facing a big problem in invasion and outbreaks of newcomer insect pests, namely the fall armyworm (Spodoptera frugiperda) (Lepidoptera: Noctuidae). S. frugiperda comes from South America (Nagoshi et al 2017;Otim et al 2018) and entered Indonesia for the first time on March 26, 2019 in West Sumatra, then in June 2019 it was found in Banten and West Java (Sartiami et al 2020) and now it has spread rapidly to various provinces in Indonesia, such as South Sumatra (Herlinda et al 2020b;Hutasoit et al 2020), Lampung (Lestari et al 2020), and Bengkulu (Ginting et al 2020). The fall armyworm has caused maize yield losses in Africa of 250-630 million US dollars per year (Bateman et al 2018).…”

“…S. frugiperda was also killed by B. bassiana, M. anisopliae, Metarhizium rileyi (Ramanujam et al 2020), and Metarhizium spp. (Herlinda et al 2020b). The entomopathogenic fungus species effectively killed S. frugiperda larvae by contact (Herlinda et al 2020b).…”

“…(Herlinda et al 2020b). The entomopathogenic fungus species effectively killed S. frugiperda larvae by contact (Herlinda et al 2020b). If the mode of action of the fungus is contacted only, the fungus is not very effective in controlling S. frugiperda larvae hidden in maize leaf midribs because the larvae only appear when eating leaves in the morning (Bentivenha et al 2017).…”