|
Forest pests of current concern Dr. Hugh Evans, moderator It has been interesting to see how topics have strayed across the Session boundaries and one of the strong themes has been the perspective of trade versus security; a nice description of this dilemma was Who is driving the coach- trade or the science. This provoked some interesting perspectives, including a view that there is no coach – "What we have here is a very traditional governmental regulatory program; one with a dual and somewhat conflicting mission". On the question of detection of cryptic organisms, such as pathogens, many contributors felt that there was either little problem – no evidence of risk, no vectors, etc. –, or that lack of detection methods is disguising the risks – "if there is a coach, Darwin is inside it", referring to the genetic adaptability of many pathogens. Clearly, this is an area that requires much more research. Disappointment at the lack of coverage of invasive plants was also expressed. This is certainly a real issue and which should be covered in any future symposium. The question of acceptable risk was also brought up by several contributors. Most reached much the same conclusion; it is impossible to provide zero risk of importation of exotic pests and diseases. Even if all plants or plant products were prohibited, illicit trade would still provide pathways, albeit at much reduced levels. It is, therefore, better to establish a working system and to recognize its shortfalls. This is, in essence, our current system and, like it or not, it does work moderately well. If resources were unlimited, we could increase the awareness of threats at all levels of the community - governmental, trade and public - and all could cooperate to reduce the overall risk. In reality, we are always working with fewer than ideal resources and so the risk must be managed (a theme that several contributors have alluded to). Most effort should be put in to the highest risk organisms and here we must recognize what risk means. It is not only the hazard posed by a potential pest but it must also take account of the likelihood of that hazard being realized, thus giving a measure of overall risk. Thus, some organisms with high intrinsic hazard might actually be low risk because the probability of movement along a pathway is very low. Conversely, relatively low hazard organisms might pose a high risk because they move so frequently along pathways and could easily establish in a new location. The sort of science described in the papers in this session illustrate how information on biology can be used to quantify the risks and also suggest mitigation measures to both reduce entry and to manage the pests if they do succeed in establishing. Exchange of information internationally is vitally important in improving PRA methods and I hope that the debate starting in this on-line workshop can lead to enhanced understanding among all concerned. This would apply, not only of the issues involved, but also to the constraints that need to be overcome to satisfy all the stakeholders involved in keeping our forests and woodlands pest free.
|