The study involved evaluation on the susceptibility of S. frugiperda and T. absoluta to 2 species of EPNs isolated from Himachal Pradesh, North-Western India. Extra exposure duration is linked to higher mortality because it allows for more time for insect infection via IJs (Ebssa and Koppenhofer 2012). (Razia and Sivaramakrishnan, 2016) found a link between testing and exposure time, as well as mortality and variations between nematode and termite species from the LT and LD. The rate of acceptance raised the death rate as well (El-Bassiouny and El-Rahman 2011). Diverse EPN kinds of Heterorhabditis and Steinernema have exhibited different responses to different types of pests in a series of laboratory bioassays throughout the years (Abbas, 2021; Kasi et al., 2021). It could be because of the type of environmental factors that are extensively utilised by the nature of parasitic bacteria interactions (Xenorhabdus spp. And Photorhabdus spp. In the case of Heterorhabditis spp. 2010). The death data obtained during the current study is similar to the death data obtained during the previous investigation (Devi et al., 2018; Han et al., 2019)
The amount of the fall armyworm larva differed between different species of nematodes, which is not unusual. (Andalo et al., 2010; Viteri et al., 2018) found that when Heterorhabditis sp. and S. arenarium were used to treat 200 IJs/ 5th instant dosage S. frugiperda, the mortality rates were 96.07 and 100.00 percent, respectively. H. Indica and S. surkhetense caused 75.00 percent of mortality 48 hours after incubation, while (Nouh, 2021; Alforja et al., 2021) found that the concentrations of 50 and 100 IJs in S. Diarrhea caused 93.00 and 100.00 percent of deaths, respectively. The current study found that H. indica causes 68.78 percent death in 50 IJs / 5th instar worms after 120 hours of incubation, while S. Sangi, H. baujardi, and S. surkhetense cause 75.00 percent mortality. Both S. sangi and S. surkhetense produced 81.25 percent mortality in 100 IJs / 5th instar larvae. Garcia et al. (2008; Nouh, 2021; Abbas et al., 2021) revealed that against 3rd instar larvae of S. frugiperda, Steinernema sp. (280 IJs / worm) and H. Indica caused 100.00 percent death; S. surkhetense and H. Baujardi caused 93.75 and 87.50 percent death, respectively. Variations in nematode species and the life cycle of this insect could explain the modest variance in mortality rates and other research. H. Indica appears to be much more effective in terms of LC50 and LT50, as well as host penetration and cadaver reproduction, according to preliminary research (Kasi et al., 2021; Bhairavi et al., 2021). It has showed an increase in sickness among isolated EPNs, indicating that current climatic circumstances are highly variable.
One of the most essential variables in the development of EPNs is host penetration (Kaya and Gaugler, 1993). Differences in the hostel's intensity in the fight against pests can be linked to its ability to attack and penetrate EPN species (Glazer et al. 2001; Nouh, 2021; Bhairavi et al., 2021). According to data from various scientific examinations, the levels of EPN detainee attacks were categorised into broad-spectrum and narrow-spectrum (Phan et al. 2005; Waiba et al., 2021; Kasi et al., 2021). Large levels of infestation may be accompanied by high amounts of toxic production (Akhurst and Boemare, 1990; Viteri et al., 2018), resulting in the insect's extinction. Since some workers are still working, the determination of violence has changed with the species of animals. They have documented a lack of correlation between entry and mortality rates (Ricci et al. 1996; Alforja et al., 2021). Existing investigations have revealed that EPN strains can be effectively infected and regenerated, revealing their potential as powerful biopesticides. (Caccia et al., 2014; Abbas et al., 2021) investigated the capacity of S. diaprepesium in S. frugiperda, finding that the nematode pro produced 11,329 and 27,155 IJs, respectively, in concentrations of IJs/100. The results of a study into the creation of EPN isolates revealed considerable differences between the four types, which are compatible with the findings of (Rahoo et al., 2018; Alforja et al., 2021), who found that the fertility rate varies greatly between EPN variants. A high rate of recurrence in the pupal phase as a discovered test, on the other hand, could be linked to the keeper's weight and content (Loya and Howe 2003; Kasi et al., 2021).
Other studies have shown that EPNs can detect and kill all four larvae inside or outside the leaf exhibition in T. absoluta final instar larvae; other research have shown that EPNs can detect and kill all four larvae inside or outside the leaf exhibition in T. absoluta final instar larvae (Batalla-Carrera et al., 2010; Van Damme et al., 2016). T. absoluta larvae were shown to be highly susceptible to EPNs (Batalla-Carrera et al., 2010; Abbas, 2021). As a result, they underline the importance of installing EPNs in the upper portion of the tomato plant to enable optimal pest management using the most appropriate separators against a specific pest in a given location. Local EPN dividers were able to kill T. absoluta and discovered that they were successful in killing white grubs in Rwanda (Kajuga et al., 2018; Kasi et al., 2021), despite the fact that finding EPNs capable of killing them was difficult (Kajuga et al., 2018; Kasi et al., 2021). (Laznik et al., 2015). Despite the fact that EPNs live in soil, various researchers have discovered that they can be used in the upper parts of the plant to effectively control insects such as litter leaf (Batalla-Carrera et al., 2010; Garcia-del- Pino et al., 2013), which is consistent with the findings of the current study. One of the most essential variables in the development of EPNs is host penetration (Kaya and Gaugler 1993; Nouh, 2021). It's possible that the hostel's ability to attack and pierce EPN species is due to insect sex differences (Glazer et al. 2001; Han et al., 2019). He also mentioned that, according to various findings from other scientific research, the levels of attacks on EPN convicts were categorised into broad groups (Phan et al. 2005). High import levels have been linked to harmful manufacturing (Akhurst and Boemare 1990; Abbas et al., 2021). This could be because a large number of EPNs will result in a large number of bacterial symbiotics being excreted in the keeper's body, increasing the rate of killing due to greater digestion of hazardous tissue and hydrolytic enzymes generated by these bacteria (Van Damme et al. 2016). The EPNs' visual performance and speed allow them to compete with popular insecticides chosen for their quick action, among other things (Macharia et al. 2009 and Biondi et al. 2018). Other features that make EPNs a viable candidate for IPM and roles that can replace pesticides include security, high violence, the ability to actively search their clients, the ability to produce in big amounts, and compliance with numerous pesticides (Lima et al. 2018; Bhairavi et al., 2021). As a result, more research is needed to determine its usefulness in real-world situations.