Effects of so-called "environmentally friendly" agrochemicals on the harlequin ladybird Harmonia axyridis (Coleoptera: Coccinelidae)

Jana Niedobova,Martin Brtnicky,Michal Skalsky,Zdenek Faltynek Fric,Vladimir Hula

doi:10.14411/eje.2019.018

Abstract

A variety of plant protection products and other agrochemicals are used in agro-ecosystems. Products approved for integrated pest management (IPM) or organic farming should have minimal negative side effects on beneficial insects. The Asian harlequin ladybird Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae) has become a widespread and important generalist predator of certain agricultural pests, mainly aphids, throughout Europe. We studied the effects of two agrochemicals, Boundary SW® (auxiliary plant protection product) and Prev B2® (foliar boron fertilizer), usually regarded as environmentally friendly and known to have insecticidal side effects against some fruit and vegetable pests (e.g., aphids, spider mites, weevils), on the last larval instar and adults of Harmonia axyridis. The conventional organophosphate insecticide Reldan 22® was used as a chemical standard for evaluating the lethal effect, because this product is usually effective against a broad spectrum of insects, and indeed was immediately lethal for both the adults and larvae of this species. However, whereas Prev B2® had no effect, adult ladybirds sprayed with Boundary SW® survived only for up to 25 h and also none of the larvae completed their development. Thus, although our experiments were not made under natural conditions, the use of Boundary SW® cannot be recommended for IPM and organic farming in terms of safeguarding insect predators such as Harmonia axyridis until further more detailed testing.

Highlights

Crop protection is usually based on a broad range of chemical pesticides and other agrochemicals, such as auxiliary plant protection products, adjuvants and fertilizers, which can have insecticidal side effects on beneficial arthropods (Desneux et al, 2007; Evans et al, 2010; Korenko et al, 2016; Niedobová et al, 2016)
Fourth-instar larvae and adults of Harmonia axyridis were used for studying the effects of two agrochemicals regarded as “environmentally friendly” but with insecticidal side effects: Boundary SW® and Prev B2®
Even though none of the tests were carried out under natural conditions, the present study demonstrated that different plant protection products approved for integrated pest management (IPM) and organic farming can vary widely in their adverse effects on larvae and adults of H. axyridis

Summary

Introduction

Crop protection is usually based on a broad range of chemical pesticides and other agrochemicals, such as auxiliary plant protection products, adjuvants and fertilizers, which can have insecticidal side effects on beneficial arthropods (Desneux et al, 2007; Evans et al, 2010; Korenko et al, 2016; Niedobová et al, 2016) Beneficial arthropods, such as predators are able to significantly suppress pest populations in agro-ecosystems (Greenstone et al, 2010, Suenaga & Hamamura, 2015). One of the currently most widespread and abundant species of the family Coccinellidae is the harlequin ladybird, Harmonia axyridis, a generalist predator that inhabits a wide range of natural as well as agricultural habitats (Brown & Miller, 1998; Seo & Youn, 2000; Koch, 2003; Snyder et al, 2004; Brown et al, 2011). Besides the role of this species as a biocontrol agent, the establishment of H. axyridis outside its native Asian range raised concerns about its possible negative effects on native insects (Brown & Roy, 2018; Masetti et al, 2018)

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Conclusion