Impairing Effectiveness of Nerolidol, a Sesquiterpene Compound, on Adult Performance and Reproductive Potential of Egyptian Cotton Leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae).

Hamadah, Kh,Karem Ghoneim,Waheeb, H

doi:10.21608/eajbsa.2020.80074

Abstract

Although Egyptian cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) is native in Africa, it is distributed throughout the world. It is a serious polyphagous insect damaging more than 90 host plants of economic importance. The objective of the current study was to evaluate the disruptive impact of Nerolidol, a Sesquiterpene compound, on the most important parameters of adult performance and reproductive potential of this insect. The newly moulted larvae of 5th (penultimate) or 6th (last) instar larvae fed castor bean leaves previously treated with 7 concentrations of Nerolidol(400, 200, 100, 50, 25, 12.5& 6.25 ppm) for 24 hr. The most important results could be summarized as follows. Nerolidol exhibited an adulticidal activity only at the higher concentrations. Nerolidol exerted an anti-morphogenic activity against adult moths since some malformed adults were produced at the higher concentrations. Regardless the treated larval instar, Nerolidol induced the successfully emerged adults to live remarkably shortened total longevity and oviposition period, but the pre-oviposition period was generally prolonged. Nerolidol exhibited an inhibitory effect on the oviposition efficiency since the oviposition rate was deleteriously regressed, in a dose-dependent course. Nerolidol caused a disturbance of the reproductive capacity since fecundity and fertility were dramatically prohibited. After larval treatment with Nerolidol, the successfully mated adult females laid eggs with a significantly prolonged incubation period, especially at the higher concentration levels.

Highlights

Egyptian cotton leafworm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is a native pest to Africa (Shonouda and Osman, 2000; El-Khawas and Abd ElGawad, 2002), it is distributed in many European countries (Pineda et al, 2007; Lanzoni et al, 2012; EPPO, 2019), Asia Minor and the Middle East countries (El-Aswad, 2007; ElSabrout, 2013; Azzouz et al, 2014)
The objective of the current study was to evaluate the disruptive impact of Nerolidol on the most important parameters of adult performance and reproductive potential of S. littoralis
Affected Adult Survival: After treatment of 5th instar larvae of S. littoralis with 7 concentration levels of Nerolidol, data of the most important parameters of adult performance were summarized in Table (1)

Summary

Introduction

Egyptian cotton leafworm Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) is a native pest to Africa (Shonouda and Osman, 2000; El-Khawas and Abd ElGawad, 2002), it is distributed in many European countries (Pineda et al, 2007; Lanzoni et al, 2012; EPPO, 2019), Asia Minor and the Middle East countries (El-Aswad, 2007; ElSabrout, 2013; Azzouz et al, 2014). S. littoralis caterpillars feed on more than 90 plant species of economic importance belonging to 44 plant families (Kandil et al, 2003; Benelli et al, 2017), such as vegetables, horticultural crops and ornamental plants (Dahi, 2005; Amin, 2007; Ismail, 2014; Sut et al, 2017). The number of attacked plants increased to more than 112 species (El-Sinary et al, 2008; El-Zoghby et al, 2011; Sut et al, 2017; Benelli et al, 2017; Al-Nagar et al, 2020)

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Conclusion