Insects fascinate me, and I want my science to have real impact. That’s why I’m teaming up with Dr Gonzalo Avila from Plant & Food Research, and Dr Greg Holwell from The University of Auckland. I started a PhD project last month to improve the way that classical biological control agents are tested before release. I’m looking at a current hot-topic in pest management: Brown marmorated stink bug.
Biological Control Shows Great Promise
Biological control is a form of pest management in which human beings use other living creatures to keep pest numbers down. Sometimes a pest invades a new area and damages crops, free from the natural enemies it left behind in it’s native range. Classical biological control involves introducing the natural enemy of a pest into a new range, in order to restore some of the natural control that normally happens in the pest’s native range. As you can imagine, this approach has many benefits, including long-term permanent control, and large reductions in pesticide use.
But there are also important risks that need to be considered. Will the biological control agent be effective against the target pest? Will the agent start attacking other species, maybe even native species? Will the agent interfere with other biological control agents, or other species that are important economically? Before a biological control agent can be released in New Zealand, the Environmental Protection Authority (EPA) must be convinced that, among other things, the agent does not pose a significant risk to New Zealand’s biodiversity.
An important starting point is understanding how likely it is that a proposed biological control agent will attack a non-target species. That’s where my PhD project comes in. I’m using a high-profile case study to improve the way that agents are screened for non-target impacts before they are approved or released. The broader goal is to define a set of methods that will provide the EPA with more confidence in it’s decisions before signing-off on the release of new biological control agents.
The Stink Bug Threat
Halyomorpha halys, aka the Brown Marmorated Stink Bug (BMSB), is a highly damaging crop and nuisance pest that has recently invaded North America and Europe from it’s native range in East Asia. It is already having massive impacts on peoples livelihoods in its invaded range, and the economic damage is only expected to increase as it spreads further. BMSB would deal a severe economic blow to New Zealand’s primary industries if it established here. Having been intercepted many times at our border, it’s only a matter of time before this pest attempts to gain a foothold in NZ.
Instead of waiting for that to happen, the B3 biosecurity collaboration is taking a preemptive approach by prioritizing research on BMSB control now, so that we have the tools to contain potential infestations. The main aim of my PhD project is to test an Asian species of parasitoid wasp, a potential biological control agent of BMSB, to see if it’s suitable to release in NZ, should BMSB establish here. Trissolcus japonicus, or the ‘samurai wasp,’ shows promise in controlling BMSB within their shared native range. Before it could ever be released here, comprehensive host-range testing would need to be undetaken to ensure it would not negatively impact our native ecosystems or other taonga.
I’ll be testing to see how this wasp responds when presented with native New Zealand stink bugs. If the risks are low, it may be given the green light for introduction against BMSB. However if it is shown to present a high risk to our native species, it is far less likely to be a part of the BMSB toolkit.