The Humoral Immunological Response and Bio-Efficiency Evaluation to Entomopathogenic Nematodes as A Biopesticide on Spodoptera littoralis (Boisd)

Shahin, Rima; Khamis, Wael M; El-Sabrout, Ahmed M.

doi:10.21608/asejaiqjsae.2023.285162

The Humoral Immunological Response and Bio-Efficiency Evaluation to Entomopathogenic Nematodes as A Biopesticide on Spodoptera littoralis (Boisd)

Document Type : Original Article

Authors

¹ Department of Applied Entomology and Zoology, Faculty of agriculture (El-Shatby), Alexandria University, Alexandria 21545, Egypt

² Plant Protection Research Institute, Agriculture Research Center, Al-Sabhia, Alexandria, Egypt

³ Applied Entomology and Zoology Department, Faculty of Agriculture(El-Shatby), Alexandria University. Egypt.

10.21608/asejaiqjsae.2023.285162

Abstract

The current study aims to investigate the residual toxicity and nutritional indices of entomopathogenic nematodes (EPNs), as well as immunological response to an infection in Spodoptera littoralis. Compared to the individual impacts of Steinernema carpocapsae, Heterorhabditis indica and EPNs binary combinations showed a higher pathogenicity to S. littoralis according to mortality, physiological responses, and humoral immune. The anti-feedant activity percentages of H. indica and S. carpocapsae treated larvae had a more potent effect than their binary mixture at LC₃₅, compared to full-feeding activity in the control. The biochemical characteristics of infected hemolymph showed a significant variation, not only in the total protein concentration, but also in the appearance of the new protein bands profile. An additional band, with a molecular weight of ~79 KDa was observed at immunized hemolymph, it has been postulated that it may be the phenoloxidase(PO), which is in close agreement with the significant induction of PO activity after infection. Interestingly, the immunised hemolymph of the larvae infected with binary combinations of EPNs showed a notably increased intensity of the major proteins and a rise in the number of antimicrobial peptides with molecular weights under 30 KDa. However, the significant reduction of total protein count and PO level, which ultimately resulting in larval death, is evidence that the binary mixture of the investigated nematodes is highly suppressed S. Littoralis larval immune system.

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