Methods Used to Assess Non-target Effects of Invertebrate Biological Control Agents of Arthropod Pests

Abstract

The number of concerns regarding potential non-target effects of invertebrate biological control agents of arthropods has risen over the last decade and an increasing number of studies have since dealt with this topic. Despite some recent international initiatives aimed at providing guidance for risk assessment of biological control agents, detailed methods on how tests should be designed and conducted to assess for potential non-target effects still need to be provided. It is believed that this review comes at an ideal time, giving an overview of methods currently applied in the study of non-target effects in biological control of arthropod pests. It provides the first step towards the ultimate goal of devising guidelines for the appropriate methods that should be universally applied for the assessment and minimisation of potential non-target effects. The main topics that are reviewed here include host specificity (including field surveys, selection of non-target test species and testing protocols), post-release studies, competition, overwintering and dispersal. Finally, a number of conclusions that have emerged from this comprehensive compilation of studies are drawn, addressing potential non-target effects in arthropod biological control.

Prey range of the predatory ladybird Cryptolaemus montrouzieri

“…These findings indicate that taxonomic relatedness in se may not necessarily be a sufficiently reliable criterion for determining prey ranges and even closely related prey may substantially differ in their suitability to support immature development and/or reproduction of a natural enemy. Furthermore, our study provides support for the hypothesis that in addition to non-target species that can easily be tested in a laboratory setting, prey range testing should give additional attention to economically important species, threatened or valued species and native natural enemies (Sands and van Driesche 2000;Babendreier et al 2005;van Lenteren et al 2006b).…”

“…Furthermore, no-choice experiments present a worst-case scenario as a positive response to a non-target prey can be artificially induced by confinement and lack of choice (van Driesche and Murray 2004b). Conducting more realistic experiments, in which two or more prey species are presented to the predator (choice test) or host plants are included in the experimental set-up (semifield test), might yield a more reliable estimation of a predator's prey range (van Lenteren et al 2003;van Driesche and Murray 2004b;Babendreier et al 2005). Thus, test species that showed to be suitable prey for C. montrouzieri in the present no-choice Petri dish experiments do not necessarily have to be at risk in a natural situation.…”

“…However, the development of a concrete experimental methodology to assess the prey range of arthropod natural enemies is still an ongoing process and several factors complicate this assessment, including the number of non-target species to be tested, the criteria for their selection, the need for reliable methods for determining prey acceptance and the discrepancy between prey ranges observed in the field and in the lab (Babendreier et al 2005;Kuhlmann et al 2006;van Lenteren et al 2006b;Hatherly et al 2009). In weed biological control, a survey across all potential host plant species in the native range of a herbivore is considered to be a good start in quantifying its degree of polyphagy (Manners et al 2011).…”

Biological control and sustainable food production

“…More recently, guidance on procedures and methods for environmental risk assessment (ERA) of non-native invertebrate biological control agents has been proposed Babendreier et al 2005;van Lenteren et al 2006b;. The biological control industry was concerned when the OECD guidance document was published, as the information requirements were considered to be too stringent, and manufacturers feared that national authorities would establish their own regulatory systems.…”

Assessing non-target effects and host feeding of the exotic parasitoid Apanteles taragamae, a potential biological control agent of the cowpea pod borer Maruca vitrata

“…A relative specialist parasitoid that has a narrow host range is expected to have a limited environmental risk, while a generalist is expected to affect non-target hosts (Henneman and Memmott 2001;Symondson et al 2002;Louda et al 2003;van Lenteren et al 2003). The host range of a parasitoid can be viewed physiologically or ecologically (Louda et al 2003;Babendreier et al 2003Babendreier et al , 2005Haye et al 2005).…”