Morphological and molecular characterization of entomopathogenic nematode, Heterorhabditis baujardi (Rhabditida, Heterorhabditidae) from Mizoram, northeastern India

Self Cite

Background Outbreak of the fall armyworm Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae) occurred in Mizoram, North-Eastern India. The infestation spread in the entire state covering a total area of around 2840 hectares of maize cultivated land. Entomopathogenic nematodes (EPNs) represent potential candidates for the biological control of S. frugiperda. In the study, the susceptibility of the pest against 4 locally isolated EPN species Heterorhabditis indica, H. baujardi, Steinernema sangi and S. surkhetense was evaluated. Results The results indicated that all the isolated EPN species showed a high rate of larvicidal and pupicidal activities against the pest. Mortality between 43.75–100.00 and 25.00–100.00% of 3rd and 5th larval instars, respectively (at concentrations 10–800 IJs/larva), and 37.50–68.75% mortality of pupae (at concentrations 200–1600 IJs /pupa) were found after exposure to the EPN species. The mortality rate of the pest showed significant variations with life stages of the host insect, nematode concentrations and incubation time. Based on the median lethal concentration (LC50), H. indica was the most pathogenic species, followed by S. sangi, H. baujardi and S. surkhetense. The LC50 values of H. indica at 72 h post-incubation were 20.26 and 62.07 IJs/larva for the 3rd and 5th larval instars, respectively, and 913.34 IJs/pupa. The penetration assay showed that H. indica had the highest penetration rate into the hosts, 27.24, 21.30 and 20.00% in the 3rd, 5th larval instars and pupae, respectively. Furthermore, all the EPN isolates were capable of successful multiplication inside the cadaver of S. frugiperda that showed significant differences with the EPN isolates and life stages of the pest. Among the isolates, H. indica showed the highest multiplication rates, 17,692.25 ± 2103.59, 8345.63 ± 785.34 and 79,146.38 ± 5943.73 IJs per 3rd instar larva, 5th instar larva and pupa, respectively. Conclusions The study revealed that the 4 species of EPNs showed a high potency against S. frugiperda, thereby having the potential to be developed as a biological control agent against the pest. Moreover, the isolated EPN species could potentially serve as alternatives for chemical insecticides and could further be incorporated into the Integrated Pest Management (IPM).

Section: Nematode Sourcessupporting

confidence: 52%

Susceptibility of the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae), to four species of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from Mizoram, North-Eastern India

Lalramnghaki

Lalramliana

Lalremsanga

et al. 2021

Self Cite

“…The morphological and morphometric studies as well as the molecular sequencing data of ITS rDNA showed that the present strains, P5 (MK256378), P6 (MK263023) and PH (MK256358), were conspecific to H. bacteriophora (Poinar, 1976) and hence described as the same species. The genus Heterorhabditis contains 16 well-described species of which only 3 have been described from India: H. indica (Poinar, 1992), H. bacteriophora (Poinar, 1976) Sivakumar et al, 1989 and H. baujardi (Phan et al, 2003) Vanlalhlimpuia et al, (2018. This is the first valid report of the existence of H. bacteriophora in Pir Panjal Range of Kashmir Valley.…”

Section: Resultsmentioning

confidence: 93%

Description of Heterorhabditis bacteriophora (Nematoda: Heterorhabditidae) isolated from hilly areas of Kashmir Valley

Bhat

Askary

Ahmad

et al. 2019

Three strains of entomopathogenic nematodes, labelled P5, P6 and PH, were isolated during surveys of agricultural soils of Pir Panjal Range, using insect baiting technique. Morpho-taxometrical studies and molecular data confirmed that these isolates belong to Heterorhabditis bacteriophora, making this finding the first report of this species from Jammu and Kashmir, India. Their distribution using a meta-analysis of GenBank records was attempted to assess. The morphology, morphometric studies and molecular data were conspecific to original description with minor deviations. Data analysis of the distribution showed that H. bacteriophora was the most ubiquitous throughout the South Africa subcontinent, but it was rarely found in Indian subcontinent having been isolated from 3 states throughout the country. As these 3 strains of H. bacteriophora are native to the hilly region of Kashmir Valley, they can be exploited for the control of target crop insect pests of the region. However, further studies are required regarding their life cycle, host range, virulence potential and survival capacity under extreme environmental conditions.

“…Among Heterorhabditis, three indigenous nematode species have been reported of which H. indica Poinar Jr et al (1992) only new species is described from India till date. The other two indigenous species from India include H. bacteriophora Poinar (Bhat et al, 2020) and H. baujardi Phan, Subbotin, Nguyen and Moens (Vanlalhlimpuia and Lalramnghaki, 2018).…”

Section: Indiamentioning

confidence: 99%

Global distribution of entomopathogenic nematodes, Steinernema and Heterorhabditis

Bhat

Chaubey

Askary

2020

Entomopathogenic nematodes (EPNs) in the families' Steinernematidae and Heterorhabditidae are obligate insect parasites. Their easy multiplication, broad host range, compatibility with chemical pesticides, and ease in application has grabbed interest among research practitioners to work on these beneficial microorganisms. Till date, around 100 valid species of Steinernema and 21 species of Heterorhabditis have been identified from different countries of the world. Extensive surveys have been conducted across the globe to isolate locally adapted EPN species and exploit them to suppress soil-dwelling and foliar insect pests in agricultural fields. Most of the new species have been described from Asia, whereas research in some Asian countries are still at infancy. Some new species have been recorded from Australia but very few surveys have been conducted in New Zealand. Likewise, less information about these tiny creatures is from Central America; however, in North America many new species have been described, some of which have been commercialized for insect pest control, whereas in South America, several native nematode species have been described and exploited as biological control agents. European countries have also been explored for EPN diversity and new species have been reported, exploited under field condition, and commercialized. Many new species and other previously described species have been reported from Africa. Despite frequent surveys in different continents of the world, number of sites touched are low and, therefore, further surveys are still needed to explore untouched geographic areas and climatic conditions, both in plantations and indigenous forests with an aim to identify and exploit additional EPN species.