Impact of nanosilver-profenofos on cotton leafworm, Spodoptera littoralis (Boisd.) larvae

Khaled Sayed Ahmed,Hassan M Sobhy,Taher A Salaheldin,Eman Mohamed Mostafa Radwan,Wafai Z A Mikhail

doi:10.1186/s42269-019-0076-z

Abstract

BackgroundThe cotton leafworm, Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt and Africa, causing significant economic loss of cotton crop yield. The frequent use of insecticides to control this insect has led to the development of a generation’s resistance to them. The need of a new, safe control method and effective insecticides has become necessary after the recent increases in environmental pollution and insect resistance. This study is devoted to developing a novel synthetic scheme to produce a pesticide nanocomposite of very high efficiency compared to the originals. The nature of its chemical binding has been investigated via Fourier transform-infrared (FT-IR) and transmission electron microscopy (TEM) techniques.ResultsIn this work, the method is based on using silver nanoparticles (AgNPS) as a pesticide carrier by loading the organophosphorus pesticide profenofos on to their surface. The profenofos, AgNPS alone and nanocomposite profenofos (AgNPS@P) have been tested against second- and fourth-instar larvae of laboratory and field cotton leafworm. Our findings indicate that the AgNPS@P is more effective on cotton leafworm larvae than each of profenofos and nanosilver alone. The activity of AgNPS@P (LC50 = 0.94 and 5.15 ppm) was increased to 85 and 69 times more than that of profenofos (LC50 = 79.52 and 356.97 ppm) against second- and fourth-instar larvae of field cotton leafworm.ConclusionsThis method may be successful for reducing environmental pollution and the resistance of this pest to many pesticides.

Highlights

The cotton leafworm, Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt and Africa, causing significant economic loss of cotton crop yield
The development of cotton leafworm resistance to the use of synthetic pyrethroids, organophosphorus, carbamates and other chemical insecticides has been correlated with the appearance of cross-resistance in many cases (El-Zemaity et al 2003)
Insects The laboratory insects are reared on castor bean plant leaves for 7 years, without any exposure to insecticides, in the Insect Population Toxicology Department, Central Agricultural Pesticides Laboratory (CAPL), Agriculture Research Centre, Ministry of Agriculture, Giza, Egypt under laboratory constant conditions

Summary

Introduction

The cotton leafworm, Spodoptera littoralis (Boisd.), is one of the most dangerous pests in Egypt and Africa, causing significant economic loss of cotton crop yield. The frequent use of insecticides to control this insect has led to the development of a generation’s resistance to them. Insect resistance is a major problem generated by the frequent use of the conventional pesticides for controlling the insect pests (Nkya et al 2014). The development of cotton leafworm resistance to the use of synthetic pyrethroids, organophosphorus, carbamates and other chemical insecticides has been correlated with the appearance of cross-resistance in many cases (El-Zemaity et al 2003). The use of pesticides causes an increase in costs and many problems of environmental and personal exposure which has led to the contamination of ground waters, plants, soil, animals and damaging beneficial non-target organisms (Kuzma et al 2006). Many insecticides are not soluble in water, so large quantities of organic solvents are required and most of these solvents contaminate the environment (Sanni and Mutta 2014)

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Conclusion