Effect of a low cost diet on the cotton leaf worm, Spodoptera littoralis nucleopolyhedrosis virus pathogenicity and sterile insect technique

Waheed A A Sayed,Helmy El-Bendary,Alexandra El-Helaly,Zakia A Jamal

doi:10.1186/s41938-021-00464-9

Waheed A A Sayed, Helmy El-Bendary + Show 2 more

Open Access

https://doi.org/10.1186/s41938-021-00464-9

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Abstract

BackgroundMass rearing cost of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the critical methods for the successful utilization of Baculovirus pathogenicity and sterile insect technique (SIT). Effectiveness of both SIT and S. littoralis Nucleopolyhedrosis Virus (SpliNPV) was assessed in response to plant-based diet and substitution of agar with commercial sources of gelling components as feed.ResultsPupal and adult recoveries produced by castor bean leaves were significantly high, followed by the agar-based diet. Moreover, larval durations were significantly prolonged for (starch + gelatin)-based diet than the other dietary diets. Obviously, SpliNPV pathogenicity against the larvae reared on (starch + gelatin)-based diet was 2.5 and 2 times higher than those reared on castor leaves and agar-based diet, respectively. Contrary to expectation, the sterility doses of male moths produced by castor leaves and agar-based diet were relatively similar.ConclusionThe findings suggest that the lowest cost diets (starch + gelatin)-based diet could be used effectively for increasing the SpliNPV pathogenicity, while either castor leaves or agar-based diet could be considered as a promising choice for SIT program.

Highlights

Mass rearing cost of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the critical methods for the successful utilization of Baculovirus pathogenicity and sterile insect technique (SIT)
The results revealed that gelling agents may be has important role for insect immunity or susceptibility against SpliNPV infection in particular the low concentrations from 1 × 102 to 105 Polyhe‐ dral inclusion bodies (PIB)/ml, the pathogenicity of virus was greatly varied by the different of larval diets, which has been expressed as larval mortality (Fig. 5), and the changes of larval color (Fig. 4), namely the infection was high in the larvae fed on SG diet (Fig. 4d) followed by agar + starch + gelatin-based diet (ASG) diet (Fig. 4c), while the larvae fed on A diet (Fig. 4b) and castor leaves-based diet (CL) diets (Fig. 4a) exhibited low virus infection
Results of SpliNPV pathogenicity indicated that the virus actions were varying by the different dietary larvae, whereas it was greatly produced by the larvae reared on-based diet, whilst the larvae reared on castor plant had the lowest susceptible level

Summary

Introduction

Mass rearing cost of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is one of the critical methods for the successful utilization of Baculovirus pathogenicity and sterile insect technique (SIT). Effectiveness of both SIT and S. littoralis Nucleopolyhedrosis Virus (SpliNPV) was assessed in response to plant-based diet and substitution of agar with commercial sources of gelling components as feed. The cotton leaf-worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is an economic pest of numerous cultivated plants in many regions. It is considered a serious polyphagous pest in different countries, attacking many vegetable and field crops worldwide (El-Helaly et al 2020). The associate cost, time, space and ingredients availability of insect food are the tools for improving the insect rearing facilities

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