Survey and identification of entomopathogenic nematodes in the province of Cotabato, Philippines, for biocontrol potential against the tobacco cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae)

Abstract

Background The tobacco cutworm, Spodoptera litura [Fab.] (Lepidoptera: Noctuidae), is a devastating insect pest of several crops. Entomopathogenic nematodes (EPNs) of the families Heterorhabditidae and Steinernematidae are used as an alternative control measure in lieu of the hazardous synthetic chemical applications. Results A survey of naturally occurring EPNs was conducted across the province of Cotabato, Philippines, covering a total of 5 municipalities with 25 villages. Galleria-baiting technique was employed to recover nematodes from peanut and grassland soils. Out of 50 soil samples collected, only 5 samples harbored nematodes, indicating a recovery of 10%. Preliminary morphological data identified only one EPN under the genera Heterorhabditis (1 isolate), whereas 4 were facultative necromenic nematodes from the genera Metarhabditis (2 isolates) and Oscheius (2 isolates). Analysis of D2D3 segments of the 28S rDNA confirmed high sequence similarity to Heterorhabditis indica, Metarhabditis rainai, Oscheius insectivora, and Oscheius sp. This is the first record of H. indica and M. rainai in the entire region, whereas the first record for Oscheius spp. in the Philippines. Furthermore, the biocontrol potential of the local H. indica infective juvenile (IJ) populations (PIGCD1) isolated from peanut was assessed against the tobacco cutworm, S. litura, under laboratory conditions. The mean percentage mortality caused by H. indica on S. litura at 7 different concentrations ranged from 0-100% at 24 h post inoculation. The lethal concentration (LC50) required to kill 50% of the S. litura larvae population with H. indica was 7.13±1 (IJs/larva). Conclusions The use of Galleria-baiting method is a convenient approach to detect EPNs including other facultative necromenic nematodes from the soils. Obtained data indicated that the local H. indica isolate can be a promising alternative measure to suppress the economically important insect pest, S. litura, and this may provide significant outlook to establish the biocontrol program in the country.

Indigenous entomopathogenic nematode as biocontrol agents for insect pest management in hilly regions

“…LC50=6.81/larva and 8.45IJ/larva was recorded when EPNs (Heterorhabditis indica and Steinernema glaseri) were applied against S. litura under laboratory conditions (42). Similar observations were recorded in the previous work in which LC50=7.13 were recorded to kill 50% population of S. litura (41).…”

“…Previously, EPNs susceptibility was also tested against different larval instars of S. frugiperda and it was reported that all the instars were highly susceptible for EPNs infection (39,40). Earlier,0-100% mortality was recorded in S. litura even after 24 h of EPNs exposure (41).…”

Entomopathogenic Nematode (Nematoda: Rhabditida) Survey and their Occurrence in Soil of District Lakki Marwat, Khyber Pakhtunkhwa Province, Pakistan

“…Huma et al (2019) first time explored six districts of Khyber Pakhtunkhwa, Pakistan including Swat, Kohat, Haripur, Chitral, Mardan, Peshawar and found positive vegetations i.e., 23.1% out of 108 samples from grassy land, tomato field, forest land and poplar trees land for EPNs (Heterorhabditis and Steinernema) existance. Another EPNs survey were also commenced from all over the world provided evidences on their occurrence (Kary et al, 2009;Valadas et al, 2013;Canhilal et al, 2016;Laznik et al, 2009;Edgington et al, 2010;Ma et al, 2010;Hazir et al, 2003;Chaerani and Indrayani, 2018;Dichusa et al, 2021). Global surveys were also supported for the presence of these valuable species and have to be commercially used for insect controlling.…”

“…N ematode and insects could be believed as utmost successful groups of invertebrate animals in the nature. Ahuja et al, 2020;Mokrini et al, 2020;Torrini et al, 2020;Salma et al, 2020;Dichusa et al, 2021) fall under the orders Lepidoptera, Coleoptera, and Diptera (Burnell and Stock, 2000). Essential parameters such as moisture, soil texture, potential of Hydrogen (PH) and organic matters are vital aspects that affecting the virulence, existence and perseverance of these nematodes (Sandhi et al, 2020).…”

Avaliação do potencial nematicida in vitro de formulações comerciais à base de Bacillus spp

“…Nematoides gênero Metarhabditis são encontrados normalmente em solos úmidos e matéria orgânica em decomposição, e apresentam comportamento bacteriófago DICHUSA et al, 2021;MEHMOOD, 2019). As espécies desse gênero que tem importância veterinária no Brasil são M. blumi, M. costai e M. freitasi (BARBOSA et al, 2016;MONTEIRO E SILVA et al, 2016; .…”