Safety in New Zealand weed biocontrol a nationwide survey for impacts on nontarget plants

Abstract

The safety record of weed biocontrol was questioned recently when examples of damage to nontarget plants were reported overseas Until now systematic investigations of nontarget feeding have not been performed in New Zealand Results of surveys looking for evidence of nontarget damage caused by 20 biological control agents released against weeds in New Zealand are presented Most agents (16) are apparently hostspecific However two species (Tyria jacobaeae and Phytomyza vitalbae) were recorded attacking native plants although their attack was very minor and predictable from hostrange testing performed prior to release For two other species Bruchidius villosus and Cydia succedana nontarget attack was not predicted from hostrange testing Larval feeding by these species was confined to mainly weedy exotic plants that are closely related to their target plants The reliability of hostspecificity testing and overall safety record of weed biological control in New Zealand are discussed

Comparing traditional methods of test species selection with the PRONTI tool for host-range testing of Eadya daenerys (Braconidae)

“…assessing the phylogenetic and ecological affinities between the target host (invading pest) and each potential non-target. For instance, published phylogenies can change over time with taxonomic revisions, such as occurred with Senecio species (Compositae) endemic to New Zealand (Paynter et al 2004), and non-targets can be overlooked as valued, such as occurred with fiddlewood (Citharexylum spinosum L.; Verbenaceae) in Australia (Manners et al 2010).…”

Safety in New Zealand weed biocontrol a nationwide pathogen survey for impacts on nontarget plants

“…Surveys were conducted throughout New Zealand, and focused on plants that are closely related to the target weeds and are therefore most at risk of non-target attack (Barton 2004;Paynter et al 2004). The objective was to search for any disease damage caused by the following five plant pathogens, all of which have been deliberately, accidentally or autonomously introduced to New Zealand.…”

“…Concerns about potential non-target impacts and risks associated with classical biological control of weeds (Howarth 1991;Simberloff & Stiling 1996) are resulting in tighter controls over the importation and release of biological control agents worldwide (Sheppard et al 2003). In New Zealand, the Hazardous Substances and New Organisms (HSNO) Act (1996) administered by the Environmental Risk Management Authority (ERMA), requires a rigorous risk analysis for the potential introduction of biological control agents that considers the environmental risk of each proposed agent to attack non-target plant species (Fowler et al 2000;Paynter et al 2004). Host testing of all pathogens for weed biocontrol is currently based on the internationally accepted host range testing systems that help delineate the host-range for potential agents (Wapshere 1974;Briese & Walker 2002;Louda et al 2003).…”

“…A comprehensive global assessment by Barton (2004) determined there were no reports of deliberately introduced fungi unexpectedly attacking non-target plants after release. However, past investigations of non-target effects of weed biocontrol agents in New Zealand have been sporadic, with systematic surveys typically carried out only at a local scale if a report of suspected non-target damage was received (Paynter et al 2004). No systematic field surveys of introduced (deliberate or otherwise) plant pathogens on non-target species had been undertaken in New Zealand.…”

“…No systematic field surveys of introduced (deliberate or otherwise) plant pathogens on non-target species had been undertaken in New Zealand. Evaluating weed biological control projects is essential to improve our ability to predict the impact and safety of future introductions and, therefore, underpin the continued use of biological control as a tool against damaging invasive weeds (Paynter et al 2004).…”