Biocidal potential of indigenous isolates of Entomopathogenic Nematodes (EPNs) against tobacco cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

Abstract

Background Entomopathogenic nematodes (EPNs) have been regarded as the most convenient strategy for insect pest management. The native strains of EPNs: Heterorhabditis bacteriophora EUPT-SD, H. bacteriophora EUPT-R, H. bacteriophora EUPT-KN, H. bacteriophora EUPT-K and H. bacteriophora EUPT-H isolated from mid-Himalayan region of Himachal Pradesh were tested in laboratory for their multiplication and virulence against 3rd and 4th larval instars of the tobacco cutworm, Spodoptera litura Fabricius (Lepidoptera: Noctuidae), the serious polyphagous pest affecting a wide range of agricultural crops worldwide. Results All the EPN strains were effective against 3rd and 4th larval instars of S. litura. Insect mortality reached 90–96% after 96 h at nematode concentrations of 150 infective juveniles (IJs)/ml. The insect mortality was also recorded at low concentrations of IJs, but the most exposure period was required. High virulence was shown by H. bacteriophora EUPT-SD 96 and 94%, followed by H. bacteriophora EUPT-R 92 and 90%, H. bacteriophora EUPT-KN 92 and 90%, H. bacteriophora EUPT-K 92 and 90% and H. bacteriophora EUPT-H 92 and 90%, respectively, against 3rd and 4th larval instars in terms of reproductive potential and killing. All the insects were alive in the absolute control. Conclusion Utilization of EPNs for the management of S. litura may be the best method to overcome the insect resistance problems and to manage the population of this insect pest. It may be an effective method and may be a partial substitute of synthetic insecticides, thus minimizing the excessive use of synthetic chemicals. The results demonstrated the potential of indigenous EPNs isolates against S. litura, but before further recommendation, multiplication field trials need to be conducted to confirm their efficacy at farm level.

The Isolation, Identification, and Insecticidal Activities of Indigenous Entomopathogenic Nematodes (Steinernema carpocapsae) and Their Symbiotic Bacteria (Xenorhabdus nematophila) against the Larvae of Pieris brassicae

“…Amongst both of these treatments, applications of different concentrations of X. nematophila caused rapid infectivity followed by insect mortality. The observations of the current findings are supported by previous observations that showed 100% larval mortality in the early instars after 96 h [45,[52][53][54]. It was also suggested that increased exposure time significantly increased larval mortality and vice versa [55].…”

Entomopathogenic bacteria and fungi as eco-safe substitutes to chemical insecticides against leaf eating caterpillars of Spodoptera litura

“…The adult and larval stages of the test insect were collected from the agricultural field and brought to the laboratory. The rearing was done in the laboratory using the methodology followed by the methods of Tomar and Thakur [32].…”

Eco-friendly approaches of zinc oxide and silver nitrate nanoparticles along with plant extracts against Spodoptera litura (Fabricius) under laboratory conditions

“… 28 , 29 Biological control presents a sustainable solution to tackle this notorious pest problem. Various biological control agents, such as predators, 30 parasitoids, 31 entomopathogenic nematodes, 32 bacteria, 33 fungi 34 – 36 and nucleopolyhydrousvirus (NPVs), 37 are widely employed and its impact on physiological and biochemical activities.…”