ISSN 1387-3547, Volume 12, Number 9 This article was published in the above mentioned Springer issue. The material, including all portions thereof, is protected by copyright; all rights are held exclusively by Springer Science + Business Media. The material is for personal use only; commercial use is not permitted. Unauthorized reproduction, transfer and/or use may be a violation of criminal as well as civil law. Biol Invasions (2010) 12:3237–3248 Author's personal copy DOI 10.1007/s10530-010-9718-7 ORIGINAL PAPER Assessing the biosecurity risk from pathogens and herbivores to indigenous plants: lessons from weed biological control Nicholas Martin • Quentin Paynter Received: 9 September 2009 / Accepted: 29 January 2010 / Published online: 20 February 2010 Ó Springer Science+Business Media B.V. 2010 Abstract Some potentially invasive herbivores/ suite of existing natural enemies. The costs of pathogens in their home range may attack plants conducting a risk assessment of a herbivore/pathogen originating from another geographic area. Methods in another country that damages plants indigenous to are required to assess the risk these herbivores/ another geographic area means that criteria will be pathogens pose to these plants in their indigenous needed for deciding which foreign herbivore/patho- ecosystems. The processes and criteria used by weed gen species should be assessed. These criteria could biological control researchers to assess the impact of include the threat classification of the plant, the potential biological control agents on a plant species amount of damage to the particular plant organs in its non-native range provide a possible frame- affected, and the importance in key ecosystems. work for assessing risks to indigenous plants. While there are similarities between these criteria such as Keywords Indigenous plants Á Natural ecosystems Á the need for clear objectives, studies in the native Insect herbivores Á Mite herbivores Á range of the herbivore/pathogen, good knowledge of Plant pathogens Á Invasive species the ecology of the target plant and taxonomy of the plant and herbivore/pathogen, and modelling of the interaction between the two organisms, there are some important differences in approach. These Introduction include the need to consider the threat classification of the plant, the likely greater risk from polyphagous Plant pathogens or herbivores entering and establish- herbivores/pathogens than oligophagous or monoph- ing in another country/geographic area may attack agous species, and the need to consider the impact of indigenous plants as well as cultivated and natura- an additional natural enemy in conjunction with a lised plants. In the past governments have been primarily concerned about protecting cultivated and beneficial naturalised plants from new pests through a N. Martin (&) variety of biosecurity measures taken at various New Zealand Institute for Plant & Food Research Limited, Private Bag 92 169, Auckland Mail Centre, points on the pathways followed by at risk goods. Auckland 1142, New Zealand These measures include inspection of imported e-mail: [email protected] produce and plants before shipment and/or at point of entry, quarantine of live plants before or after Q. Paynter Landcare Research, Private Bag 92 170, Auckland Mail entry, and mandatory physical or chemical treatments Centre, Auckland 1142, New Zealand of plants and produce before or after entry into the 123 3238 Author's personal copy N. Martin, Q. Paynter importing country (Sumner 2003). The types of plants home range and even less information about treatments reflect the perceived risks and the path- what the impact of herbivores and pathogens living ways followed by the goods. Today, many countries other geographic areas may have on indigenous are equally concerned to protect their indigenous plants in their home range. One potential source of plants from pests, indeed the International Plant information about these herbivores and pathogens is Protection Convention (IPPC), hosted by the Food to document those found on indigenous plants living and Agriculture Organization of the United Nations outside their indigenous geographic area. A New (FAO), has recently re-interpreted its mandate to Zealand government-funded research project ‘‘Using include the protection of plants in natural as well as expatriate New Zealand flora as predictors of threats agricultural systems (Waage and Mumford 2008; to NZ natural ecosystems’’ (www.b3nz.org/public/ IPPC 2005). natural_ecosystems.php) that was part of the Better To protect indigenous plants from herbivores and Border Biosecurity (B3) programme, aimed to iden- pathogens from different geographic areas, biosecu- tify foreign herbivores and pathogens that may be rity authorities must identify high risk pathways by harmful to New Zealand indigenous plants in natural which these organisms may enter the country and to ecosystems. It did this through a survey of literature put in place measures to reduce the risk of entry and examination of New Zealand plants growing in through these pathways. This requires knowledge of other countries by New Zealand researchers visiting the biology of the organisms in their current geo- plant collections in these countries or by arranging graphic areas and an assessment of the likelihood that for researchers living in other countries to examine they will establish in the new geographic area. For these plants and report on diseases and pests. There crops, there are lists, often extensive, of the kinds of was relatively little information about herbivores and diseases and pests that can attack them, e.g. Crop pathogens in other countries that could attack plants Protection Compendium (2004), and for many of endemic to New Zealand, though there is more these pests there is often substantial information about information in the literature about non-endemic their biology, and potential damage they may cause to indigenous plants (those present naturally in New crop plants. There are standardised procedures for Zealand and other countries) (Plant-SyNZ database assessing these risks to crop plants and for identifying 2009). In summary, the Plant-SyNZ database con- pathways into the country (e.g., Anonymous 2006). tains information on 51 herbivores that are not in These procedures include hazard identification, New Zealand and that could live on 25 species of assessing the likelihood of entry, the likelihood of New Zealand indigenous plants. Nine species of plant establishment and the consequences of establishment. are listed as endemic (19 host associations) and 16 These procedures are time consuming and may involve species of non-endemic indigenous plants are listed preliminary hazard identification and prioritisation. In (40 host associations). some countries such as New Zealand, part of the Having identified herbivores and pathogens in standard procedure includes an assessment of the risk other geographic areas that live on indigenous plants of crop diseases and pests to indigenous plants. An in the target area, the next step is to determine the risk organism that may be a threat to indigenous plants that these pathogens and herbivores pose to the requires information about the impact of the herbi- indigenous flora, especially in their indigenous eco- vore/pathogen to the plant species in a geographic systems. Some herbivores and pathogens from other area where the herbivore/pathogen are present and an geographic areas will already be living in the target assessment of the consequences of establishment of geographic area and some will be living on indige- the herbivore/pathogen in the new geographic area for nous plants (e.g. Table 1). The extent of their threat it to be classified as a potential hazard. If the risk is to indigenous plants can be assessed in situ. In perceived to be high, then a full risk assessment is contrast, for herbivores/pathogens that are not present undertaken which includes pathway analysis and in the target geographic area, information about the identification of steps to reduce the likelihood of severity of their impact on indigenous plants and their entry and establishment (Anonymous 2006). possible impact on indigenous ecosystems must be There is relatively little information about the gathered in other geographic areas where these susceptibility of indigenous plants to crop pests in the herbivores/pathogens live. However, if a foreign 123 Assessing the biosecurity risk from pathogens Author's and herbivores personal copy 3239 Table 1 Summary of adventive herbivores present in New Zealand and found on New Zealand indigenous plants (Plant-SyNZ database Plant-SyNZ database 2009) Herbivore group Number of species Number of indigenous host plant associations Endemic plants Non-endemic plants Total Acari 6 12 3 15 Coleoptera 22 29 14 43 Diptera 6 7 10 17 Hemiptera: Coccoidea 26 195 46 241 Hemiptera: other 50 142 44 186 Isoptera 1 1 0 1 Lepidoptera 12 14 11 25 Thysanoptera 4 30 10 40 Mollusca: Gastropoda 1 2 0 2 Total species/associations 128 452 143 595 herbivore/pathogen is found to cause severe damage biological control agents for weeds and compare the to a plant growing in a non-indigenous geographic processes for herbivores and pathogens. This paper area, can it be assumed that the herbivore/pathogen considers herbivores and pathogens together as both will cause equally severe damage to the plant in the kinds of organism threaten indigenous plants in their plants native ecosystem? indigenous ecosystems. Research reported