A survey was conducted to isolate indigenous EPN, specifically from the northeastern part of India, a biodiversity hotspot region, to record the occurrence and their further use as biological control agent. The morphological and molecular analysis (ITS rDNA for and 16S rRNA for) revealed that the entomopathogenic nematodes isolated from four different habitats and its symbiotic bacteria are conspecific with and respectively. The phylogenetic analysis based on maximum parsimony (MP) revealed that belongs to-- group. The study constitutes the first report of and its symbiotic bacteria outside the type locality, Vietnam, and in particular from India.

Isolation of entomopathogenic nematodes from Mizoram, northeastern part of India includes a species never been recorded in India. The morphological and multigene (ITS rRNA, 28S rRNA and COI) sequences analysis had revealed that the isolated belongs to , originally described from Vietnam. The phylogenetic tree (both MP and ML) revealed that the belongs to clade, and further, forms a monophyletic clade (99/98% and 94/92% bootstrap support for ITS and 28S respectively) with, , and forming sub clade. The multigene characterization revealed that both the ITS and 28S rRNA showed similar result in resolving the phylogenetic relationship of the genus , with the ITS rRNA being superior based on the strong bootstrap support, whereas, the cytochrome c oxidase I (M1-M6 partition) can be a good supportive tool for species delimitation. This is the first report of from India envisaging its future use as a biological control agent, and further incorporated into the IPM.

Ginger soft rot disease caused by fungal pathogens have become one of the most serious problems causing reduced production around the world. It has also caused a major problem among farmers of Mizoram state in India resulting in a huge decline in rhizome yield. However, the exact causative agents of this disease have not been identified in the state. Therefore, the present study was undertaken to isolate and characterized the causative agents of ginger soft rot disease from the diseased plants collected from five different villages of Aizawl district, Mizoram. Isolated fungi were cultured and morphological and molecular identification were done using internal transcribed spacer of rDNA. Fusarium oxysporum, F. solani and Plectosphaerella cucumerina were identified in ginger samples from five villages. Fusarium spp. were the most common and seem to be the major causative agents. It is suggested that further investigation is required to explore the diversity of ginger soft rot pathogenic fungi in the whole state which could be helpful in introducing effective and eco-friendly disease management programme.

The present study was conducted to isolate and characterize symbiotic bacteria of the genera Xenorhabdus and Photorhabdus associated with entomopathogenic nematode isolated from Mizoram, NorthEastern India and screening of their antifungal activity against Fusarium oxysporum. Symbiotic bacteria were isolated by macerating infective juveniles of entomopathogenic nematode (EPN) and subsequently plated on nutrient agar supplemented with 0.0025% bromothymol blue and 0.004% triphenyltetrazolium chloride (NBTA). 16S rRNA gene was further sequenced for molecular characterization of isolated bacteria. Screening of antifungal activity was conducted by placing 4 mm of fungal 7 mycelium on petri-plate consisting of spread bacterial suspensions adjusted to 3 × 10-1 CFU ml. The morphological and molecular characterization (16S rRNA) revealed that three species of symbiotic bacteria were isolated, Xenorhabdus vietnamensis from Steinernema sangi, Xenorhabdus stockiae from S. surkhetense and Photorhabdus luminescens akhurstii from both Heterorhabditis indica and H. baujardi. The maximum likelihood tree showed that X. vietnamensis was a sister species of X. japonica; X. stockiae formed a sister group with X. doucetiae, X. nematophila, X. magdalenensis, X. cabanillasii and X beddingii whereas Phototorhabdus luminescens akhurstii formed a sister group with P. luminescens hainanensis and P. luminescens thracensis. The screening of antifungal activity revealed that all the isolated bacterial symbionts successfully inhibited the growth of Fusarium oxysporum showing the potential of entomopathogenic bacteria as biological control of pathogenic fungi. The present study constitutes the first report of symbiotic bacteria, X. stockiae and P. luminescens akhurstii from Mizoram which contributes to the regional diversity of bacteria. The results emphasized significant toxicity of bacterial isolates against F. oxysporum to a great extent, conveying the prospective of isolates as a sustainable biological control agent in future.

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).