Assessing safety of biological control introductions.

Abstract

Biological control is an important component of pest management systems. It was generally considered safe and sustainable until the validity of this consensus was challenged by researchers who pointed out that there was a lack of study, and hence evidence, to support it and provided examples of non-target impacts. Biosafety of biological control subsequently received considerable attention from both biocontrol practitioners and regulators. Many countries now have legislation in place, which is focused on risk assessment for biological control and protecting native and valued biota and the environment from potential adverse impacts. This review summarizes the biosafety debate and characterizes the direct and indirect risks of biological control mainly for weeds and insect pests. During a biological control programme, there are several ways in which aspects of biosafety can be considered and addressed: exploration in the native range of the target species; from literature and knowledge of the biological control agent and host; experience from use of the biological control agent elsewhere; and host-range tests. The value of post-release monitoring and retrospective studies for validation of pre-release predictions is discussed. A poorly studied aspect is analysis of the population impacts of non-target attack by biological control agents. The literature from the last 20-30 years can help define some useful principles by which a risk assessment can be conducted to minimize adverse environmental effects. It has become clear over this period that comprehensive assembly of information and robust quarantine testing to provide a well-structured risk assessment can reduce uncertainty in decision-making in this area.

Weevils as Targets for Biological Control, and the Importance of Taxonomy and Phylogeny for Efficacy and Biosafety

“…The latter is one of the key datasets that regulators have on which to base their assessment of risk to native and non-target species in the new proposed area of introduction [6]. In Europe, a Commission of the International Organisation for Biological Control, established to harmonize regulations, recommended that a list of all known hosts from the natural range and new areas of introduction should be documented [7].…”

The status of biological control and recommendations for improving uptake for the future

“…Some countries require analyses of risks and benefits, and decisions are made on the basis of this balance (ERMA New Zealand 1998;Sheppard et al 2003;Klein et al 2011), whereas others, such as Australia, do not consider benefits as part of the standard regulatory process because the target status of the pest has already been accepted (Sheppard et al 2003). Post-release studies to validate decisions are rarely required by regulators, but where these studies are conducted, very valuable information can be made available and used in future decision support (Barratt 2011). Further research such as this to validate predictions made pre-release can only improve our ability to more accurately predict success and safety of biological control.…”

“…The point has been made many times that measuring parasitoid attack rates, or percent parasitism does not provide information about population impact (Barlow et al 2004;van Driesche et al 1991;Barratt 2011). In some cases a 90% attack rate for a pest species that is r-selected (highly fecund but low survival of offspring) will be ineffective.…”

Pre‐emptive host‐specificity testing of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) reveals high parasitism levels against the endemic New Zealand alpine shield bug in laboratory no‐choice tests

“…Many countries require that candidate BCAs undergo host-specificity testing to ensure agents are fit for purpose and do not pose unnecessary risks to local biota (Hunt et al 2008(Hunt et al , 2011Sheppard & Warner 2016;Heimpel & Cock 2018). Pre-release risk assessment frameworks emphasise the importance of defining a BCA's physiological (= fundamental) host range, defined as the group of species in the introduced range that are accepted as hosts, and are compatible for development of the agent (Van Driesche et al 2004;Babendreier et al 2005;Bigler et al 2006;van Lenteren et al 2006;Barratt 2011). No-choice oviposition tests are commonly used for this purpose because they provide unambiguous evidence of both host acceptance and developmental compatibility (Van Driesche et al 2004).…”

“…2006; van Lenteren et al . 2006; Barratt 2011). No‐choice oviposition tests are commonly used for this purpose because they provide unambiguous evidence of both host acceptance and developmental compatibility (Van Driesche et al .…”