Available online at www.sciencedirect.com New pest threats for sugarcane in the new bioeconomy and how to manage them Franc¸ois-Re´gis Goebel1 and Nader Sallam2 Global travel, world trade and change in climate conditions increase the risks from pest and disease incursions and outbreaks in many agricultural systems. This emphasises the vital importance of biosecurity in pest management, a set of preventive measures to reduce such risks. Sugarcane is grown in many countries worldwide and is known to host more than 1500 insects and 80 diseases, but the vast majority have restricted geographic distributions. However, the adaptability of some pests and their incursion into sugarcane areas can be surprising and very costly. Sugarcane and maize are the two main commodities already responding to the pulls of the new bioeconomy. The expansion of sugarcane regions for biofuel production changes both the biosecurity risks for movement and the local potential impacts for pest communities. Pest management strategies will need to adapt. This is equally true for managing new pest incursions as it is for agronomic practices that may lead to a shift in pest pressure and dynamics. This review considers the changes in the global sugarcane industries resulting from the new bioeconomy and the risks and required responses for managing the biosecurity threats and pest management of arthropod sugarcane pests. From historical examples, it is shown how the sugarcane biofuel production systems are threatened by economically important pests and what research is needed to implement future pest management solutions. Addresses 1 CIRAD, Unite´ de Recherches Syste`mes de Culture annuels, Avenue Agropolis, 34398 Montpellier, France 2 BSES Limited, PO Box 122, Gordonvale, QLD 4865, Australia Corresponding author: Goebel, Franc¸ois-Re´gis ([email protected]) Current Opinion in Environmental Sustainability 2011, 3:81–89 This review comes from a themed issue on Terrestrial systems Edited by Andy W Sheppard, S Raghu, Cameron Begley and David M Richardson Received 28 July 2010; Accepted 14 December 2010 Available online 15th January 2011 1877-3435/$ – see front matter # 2010 Elsevier B.V. All rights reserved. DOI 10.1016/j.cosust.2010.12.005 Introduction: sugarcane, a multiple resource crop in a changing environment The sugarcane crop possesses a tremendous potential for the production of a wide range of carbon-chain molecules. The whole plant can be transformed and its www.sciencedirect.com biomass contains higher proportion of lignin, cellulose and hemicelluloses than any other C4 crops, such as sorghum and maize [1]. Today, sugarcane is considered as a multi-usage crop serving a variety of sectors from food and pharmaceuticals to energy production. Recent advances in industrial biotechnology are providing new opportunities to capture additional revenue streams from bioproducts (e.g. bioplastics) using sugarcane stalks and residues (‘bagasse’) as energy feedstock [2]. Sugarcane is grown on over 20 million hectares in over 110 countries and the production ensures the incomes of millions of growers in many rural areas. Almost 80% of the world sugar is produced from sugarcane, mainly in developing and emerging countries (Table 1) [3]. Brazil is the largest sugar producer with 33 million tons in 2008/2009 and is also the world’s second largest producer of ethanol (22.5 billion l in 2007/2008) after the USA [3,4]. In 2008, both countries covered nearly 90% of the total fuel ethanol production [4]. The Global Renewable Fuels Alliance (GRFA) predicts that global production will increase 16% in 2010 to 85.9 billion l up from 73.9 billion l in 2009 [3]. Ethanol is still mainly produced from the fermentation of sugar and in Brazil this industry has been in existence for almost 40 years, with the advantage of providing both products, sugar for food and biofuel for the transport sector [2]. This country is now moving towards second generation biofuels from the degradation of cellulosic compounds in bagasse, as are many other countries. The potential is tremendous as a yield of 100 tons of biomass per hectare (10 times sugar yields) can produce 7500 l of ethanol. This yield potential is also substantially higher than other gramineous ‘biofuel’ crops (maize, sweet sorghum, miscanthus, etc.). The bagasse can also be used in co-generation systems to provide electricity for different mill activities in addition to fibre products (e.g. paper and fibre board). The use of multiple products from sugarcane redefines the way to manage the crop and process the stems at the mill. As the consumption for sugar will not decrease in developing and emerging countries, more agricultural land is needed for biofuel production [4]. Brazil has recently been very active to convert agricultural and pastoral lands into sugarcane areas, but at a risk to natural ecosystems [2]. Even though much progress has been made to reduce the environmental impact of sugarcane production, there are issues with the expansion of sugarcane, such as water, soil and air pollution (chemicals, fertilisers, burning at harvest), competition with food crops, soil erosion and compaction (during land preparation and harvest), deforestation and habitat loss and impact on Current Opinion in Environmental Sustainability 2011, 3:81–89 82 Terrestrial systems Table 1 Main sugarcane producers and production data (2008/2009). Countries/regions Rank Brazil India China Thailand Mexico Australia Pakistan USA Indonesia Colombia Argentina South-Africa Guatemala 1 2 3 4 5 6 7 8 9 10 11 12 13 Sum World Sugar (million T) Cane (million T) Area harvested (million ha) 32.9 16.1 12.5 7.5 5.2 4.8 3.5 3.0 2.9 2.5 2.4 2.3 2.2 569.4 272.0 113.7 66.4 42.2 31.7 51.5 27.8 25.3 38.5 21.3 19.3 20.1 7.40 4.41 1.20 1.00 0.66 0.38 1.00 0.36 0.33 0.45 0.31 0.31 0.22 97.8 117.5 1316.6 1524.4 a 18.03 19.50 Cane yield (T/ha) 76.9 61.7 67.5 66.5 64.1 83.5 52.0 77.2 76.7 85.5 69.4 62.1 91.6 Source: FO LICHT Sugar Year Book 2010. a Estimate. T/ha = tons per hectare. biodiversity [2]. These issues are evident in developing countries belonging to the African, Caribbean and Pacific Group of States (ACP) due to the lack of strict regulations. Today, with the expansion of sugarcane areas, increase in world trade and ongoing climate change, more biosecurity risks and threats are expected in producing countries. For example, a suite of pests in a particular area is likely to change and evolve rapidly with often important yield reductions [5,6]. In this paper we provide an overview of key sugarcane pests worldwide, give examples of recent pest incursions and outbreaks, and then describe factors that influence pest dynamics and drive pest management systems in the context of intensive biofuel production. We then discuss ecologically based pest management approaches for minimising future pest risks. Sugarcane pests of economic importance Sugarcane (Saccharum officinarum L.) is a large tropical perennial crop growing 2–6 m high and being harvested annually for up to five years before requiring replanting. Sugarcane varieties are highly polyploid and aneuploid interspecific hybrids (2n = 100–130). Sugarcane is attacked by a wide range of insects [7], including over 1500 species worldwide [8] in addition to more than 80 diseases due to bacteria, fungi, phytoplasmas, viruses and nematodes. This review focuses on arthropod pests where the major pests cause significant damage to all stages and parts of the crop (i.e. root, stalks and foliage) [9,10]. The major groups are: Leaf feeders include armyworms (Lepidoptera, Noctuidae) and locusts (Orthoptera: Acrididae). Such pest dynamics are unpredictable in nature and certain species cause intermittent outbreaks [11]. Intensive use of mechanical harvesting and the use of thrash blankets along the sugarcane rows can provoke armyworm outbreaks. Current Opinion in Environmental Sustainability 2011, 3:81–89 Sap feeders are mostly Hemipteran species, including aphids (Aphidoidea), scale insects (Coccoidea), whiteflies (Aleyrodidae), mealybugs (Pseudoccidae), planthoppers (Fulgoroidea) and froghoppers (Cercopoidea), Directly feeding on the plant sap is compounded by some species being known disease vectors. The sugarcane aphid, Melanaphis sacchari Zethntner vectors two viral diseases of sugarcane; Sugarcane Mosaic virus (SCMV) and the recently discovered Sugarcane Yellow Leaf virus [12]. The viral Fiji disease is vectored by the delphacid Perkinsiella saccharicida Kirkaldy. These pests are cosmopolitan so the maintenance of strict quarantine procedures is needed to ensure protection against these major diseases. Stalk feeders can be loosely classified depending on the time of infestation and the feeding site into top feeders, stem feeders and shoot feeders. Moth borers predominate and are by far the most damaging sugarcane pests in all cane growing countries, except Australia and Fiji [13]. Around 50 species of moths in the genera Chilo, Eldana, Sesamia, Diatraea, Scirpophaga, Eoreuma, Tetramoera and Acigona that attack sugarcane worldwide [7,14]. Many are polyphagous readily attacking other gramineous crops (maize, rice, millet, and sorghum) and wild grasses [14] which provide pest refuges complicating crop-pest interactions. Larval damage reduces biomass and sugar content [15]. Moth borers are difficult to control because their larvae are inaccessible inside the cane. Therefore, biological control and varietal resistance are main components of their management. Root feeders are mainly white grubs (scarab beetles) which cause plant drying and increased risk of the canes collapse. Members of the subfamilies Dysnatinae, Rutelinae and Melolonthinae, the most damaging genera are Hoplochelus, Dermolepida, Lepidotia, Heteronychus, Adoretus www.sciencedirect.com New pest threats for sugarcane in the new bioeconomy and how to manage them Goebel and Sallam 83 and Anomala. Soil applications of chemical granules and entopathogenic fungi are used to control them [16]. Other pests include weevils, termites, wireworms and leaf beetles. Within the sugarcane agrosystem, there is also a myriad of predatory arthropods (e.g. spiders, ants and wasps) and other beneficial organisms that play a major beneficial role in pest suppression [17,18]. Parasitoid wasps such as Cotesia flavipes (Cameron) and Trichogramma spp. provide an effective control of eggs and larvae of stemborers [15,17]. Pest incursion, a threat for sugarcane industries: why biosecurity matters Pest incursions are on the increase and can curb the local economic viability of sugarcane production systems. Here are four recent examples: In 1973, in Re´union Island (French Overseas Department), the white grub Hoplochelus marginalis Fairmaire was accidentally introduced from its native range in Madagascar in potted ornamental plants and in 10 years became a threat to the whole sugar industry [19]. This pest found optimum field conditions for rapid population growth assisted by a lack of predators, parasitoids and entomopathogenic fungi that ensure a natural control in Madagascar. After years of chemical control through the 1980 s, an effective fungus Beauveria brongniartii (Saccardo) Petch, was discovered in Madagascar on another species of Hoplochelus and introduced into Re´union Island where it successfully controlled the pest in most sugarcane areas [19]. As a generalist this grub also infests other crops and wild grasses and so its continued suppression by this fungus remains fragile. Re´union sugarcane industry biosecurity is continually threatened by its proximity to Mauritius, Madagascar and the African mainland and the presence of many potential sugarcane pests there. In 2007 a new white grub (Alissonotum piceum besucheti Endro¨di) arrived from Mauritius. Similarly H. marginalis is a major biosecurity threat for sugarcane in Mauritius. Both countries have now reinforced quarantine and biosecurity measures at points of entry to protect their sugarcane industries against future incursions. In South Africa, the introduction of Fulmekiola serrata (Kobus, 1892) (Homoptera: Thripidae) in 2004 supposedly from the islands in the Indian Ocean took the sugar industry by surprise, particularly in the province of KwaZulu-Natal, where the bulk of the South African sugarcane crop is grown. Its rapid spread, which was associated with a severe drought, has put the South African Sugarcane Institute (SASRI) on alert and research programs are currently focused on this pest to find a control strategy. In situations of high infestation, this pest is expected to cause yield losses between 18% and 27% (tons cane/ha) and between 16% and 24% (tons sucrose/ha) [20]. A second threat for this country’s sugarcane industry is www.sciencedirect.com the spotted stemborer Chilo sacchariphagus Bojer (Lepidoptera: Crambidae). South Africa already has a stemborer problem caused by the native species Eldana saccharina Walker (Lepidoptera: Pyralidae). The spotted stemborer is a major pest in many Asian countries, Reunion and Mauritius [21] and was introduced into Mozambique in 1999, where it is currently causing economic losses in the Mozambican sugarcane areas near the Zambezi River [21]. As a result of the threat to South Africa, the sugarcane industry there has implemented a biosecurity strategy based on pest surveillance at the border and a planned rapid response [22]. In Brazil, the stemborer Diatraea saccharalis F. (Crambidae) has been a major pest in the sugar industry for many years, but successful biological control has kept this pest below economic impact thresholds most of the time [23]. However, in 2008, the giant cane borer Telchin licus Drury (Lepidoptera: Castniidae), which is common in Brazil’s northeastern states on other crops, was recorded for the first time in Sao Paulo, the largest sugarcane growing state. The larva (7–8 cm long) causes severe damage to the cane internodes and reduces biomass and sugar yields significantly reducing both sugar and ethanol production. Sao Paulo accounts for about 60% of the national sugarcane crop and has the world’s highest yield. The borer has spread across all sugarcane areas and is currently invading the centre and south of Brazil. As there is no efficient natural ennemies of this pest, development of control strategies with insecticides and genetically modified cane varieties using toxins of the bacterium Bacillus thuringiensis (Bt) is underway [23,24]. Australia grows sugarcane in tropical Queensland and Western Australia and is constantly threatened by exotic pest incursions from close proximity to Papua New Guinea and Indonesia, two other sugar producing countries and also known for their rich biodiversity. For example the sugarcane smut Ustilago scitaminea H. & P. Sydow arrived from SE Asia into Australia in 2006 after sugarcane plantations were placed in northern Western Australia into the path of Asian air currents and from there spread to Queensland [25]. Generally Australia is known to have one of the best biosecurity and quarantine systems in the world implemented by the Australian Quarantine and Inspection Service (AQIS). The Australian sugarcane industry so far remains free of any major moth borer pest problems. Pathway analysis showed that 22 of the 36 exotic moth borer species elsewhere in the world have the potential to invade Australia (BSES Limited, unpublished data). The borer species considered to have greatest potential to cause economic harm are presented in Table 2. These pests are considered to present severe consequences for the capacity of the Australian sugar industry to develop a viable biofuel and other bioproduct capacity [13,26,27]. As a result the industry has developed an Industry Biosecurity Plan (IBP) with Current Opinion in Environmental Sustainability 2011, 3:81–89 84 Terrestrial systems Table 2 High threat stemborers for Australia in order of importance. Moth borer species World distribution Sesamia grisescens, S. inferens PNG, Japan, central and South East Asia, Indonesia Scirpophaga excerptalis Central to South East Asia, Indonesia and PNG Chilo sacchariphagus, C. infuscatellus, C. auricilius, Chilo spp. India, Thailand, Indonesia, PNG, Indian Ocean Islands, Africa. Diatraea saccharalis, Diatraea spp. South and North America (Louisiana, Florida, Texas) Caribbean Islands Eldana saccharina Many sub-saharan countries in Africa esp. South Africa state and federal government agencies which evaluates the risks and entitles them to government assistance in emergency response should there be an incursion through an Emergency Plant Pest Response Deed (EPPRD) [26]. Through this planning, potential pests are categorised based on risk and the category determines the proportion of the response costs the industry will need to bear, which ensures ‘who will pay?’ does not get in the way of a rapid response. Key agronomic and ecological factors likely to change pest infestation with the sugarcane expansion for biofuel production A key question is whether massive increase of global biomass production is likely to change pest-plant interactions? It would be difficult to predict dramatic changes in pest populations simply from a switch in sugarcane from sugar to ethanol and other non-food by-products. However, further intensification of agronomic practices and land use change, the incorporation of crop genetic improvements and altered harvest regimes should lead to predictable shifts in pest and beneficial natural enemy communities in new biofuel sugarcane areas. Increased scientific understanding of landscape effects on spatial crop–pest–natural enemy interactions will be needed to sustain pest suppression. The sharing of generalist pests across sugarcane and existing gramineous crops (e.g. maize and sorghum) and other biofuel options (e.g. miscanthus and giant reed) will have broader consequences on pest dynamics in all these species in the same agricultural landscape. A number of studies and experiences are Current Opinion in Environmental Sustainability 2011, 3:81–89 Risks for Australia and control options S. grisescens is a major sugarcane pest in PNG causing yield reduction in biomass. Can be controlled by insecticides but biocontrol and varietal resistance are also used. Highest category 2 pest so far in IBP given close proximity and climate matching and as such that government would cover 80% of response costs. Kills the top of cane (‘top borer’) but not the cane stalks or cane internodes. Close proximity, climate matching and lack of an effective control strategy make this a high threat for Australia. Next highest threat for Australia is C. sacchariphagus, given close proximity in Indonesia, but effective control strategies exist for all Chilo species using inundative biocontrol using egg, larval and pupal parasitoids. Attacks cane internodes and bores wide/deep tunnels reducing sguar and biomass production. D. saccharalis is a widely distributed generalist grass stem borer in wild grasses, sugarcane and maize causing high yield reductions. Brazil and many other countries maintain levels below economic thresholds (5% internodes bored) using egg and larval parasitoids. Medium risk for Australia. This species is present in regions of Africa and has a wide range of host plants including Papyrus (its original host). The pest is hard to control using parasitoids because of its cryptic biology. In South Africa, varietal control and insecticides are used. Medium risk to Australia. showing these effects and their predictability in different cropping systems [28–30,31]. Key factors known to strongly influence the sugarcane pest and beneficial arthropod communities are summarised in Figure 1. Habitat destruction, biodiversity loss and impact on beneficial insects Agricultural intensification and large-scale monocultures lead to considerable losses in habitat and biological diversity at multiple spatial and temporal scales [32,33]. Changes to a simpler landscape structure and an overall reduction of native remnant communities alter movements of insect pests and natural enemies and increase pest infestation levels and the likelihood of pest outbreaks in other cropping systems [34,35]. In South Africa, small scale sugarcane farms (<2 ha) have 2–3 times lower infestation levels of the stemborer E. saccharina than in larger commercial farms predominated by crop monocultures [36]. The small farms are a diversification of crops interspersed with mixed marginal and natural vegetation and pests are probably naturally suppressed as such landscapes are better at supporting natural enemy diversity. Sugarcane appears therefore to be no different from other cropping systems and the move to increased production intensity and larger new areas devoted to sugar cane for biofuel will negatively impact a natural capacity for pest suppression. This will be no different if marginal lands are converted to sugarcane for biofuel production. In developing countries (e.g. Africa and South East Asia), economic pressures will be to capitalise on an emerging bioeconomy and grab existing fertile land to www.sciencedirect.com New pest threats for sugarcane in the new bioeconomy and how to manage them Goebel and Sallam 85 Figure 1 Use of susceptible varieties (including GM sugarcane) in high infested areas Si-deficient soils Over application of nitrogen PEST OUTBREAK AND RESURGENCE Poor quality of sugarcane setts, poor germination Misuse or overuse of pesticides Proximity of other gramineous crops with shared pests Biodiversity loss, lack of beneficials due to vegetationclearance, fragmentation Water stress due to mismanagement (or malfunction) of ri rigation systems, poor drainage. Harvesting delay , trash blanketing , burning at harvest Current Opinion in Environmental Sustainability Main management practices and environmental constraints likely to the change pest pressure. capture such benefits for the local economies. All of this will likely lead to increased sugarcane and homogeneity in the landscape. It will be critical to understand the impacts of landscape diversity on maximising natural pest control potential, particularly from parasitoids, at different scales while also maximising production. The amount of clearance of native vegetation to create new sugarcane biofuel areas and how this will affect pest outbreaks and natural control is the first aspect to consider. Indeed the effectiveness of active biocontrol practice in sugarcane agrosystems may also suffer from natural habitat clearance and compromise the many successes of biocontrol in regulating sugarcane pest populations. Augmentative releases of biocontrol parasitoids, will be more effective in the long term if suitable habitats for sustaining these parasitoids are already in place [32]. Understanding multi-use landscape design, including restoring some native vegetation has been shown to improve pest control strategies in other cropping systems [37]. Crop husbandry, overuse of fertilisers and silicon deficiency: a strong influence on pest population dynamics Sugarcane farming practices such as burning at harvest, still in use in developing countries in Africa and Asia, have a significant impact on biodiversity and cause the immediate destruction of the natural enemy communities important for pest control [17]. The environmental concern of burning has led many countries to implement ‘green harvesting’ which is also believed to reduce pest incidence. Poor quality of sugarcane sets used for new plantations, over use of nitrogen and positive water stress due to poor drainage or irrigation malfunctions can also increase pest infestations [38,39]. www.sciencedirect.com The link between nitrogen inputs and pest abundance (particularly aphids and mites) is well understood in a wide range of crops (apple, beans, tomato, sorghum, etc.) [40]. In South Africa, a positive correlation between nitrogen input and pest infestation levels exists for the African stalk borer E. saccharina [36] and proved to be another factor leading to lower pest prevalence on small scale farms there. The critical threshold of 100 kg N per ha was found to agree with results obtained in Cuba for D. Saccharalis [41]. There is a tradeoff between fertiliser inputs to increase productivity and associated increased losses to pests. Silicon content of the plant tissue also enhances resistance to pests and diseases [42]. Water stress, during droughts for example, seems to induce greater polymerisation of silicon or changes its structure within plant tissues, leading to a harder external barrier associated with the cell walls, through which larvae must penetrate. In South Africa, silicon content in sugarcane adversely affects the biology of E. saccharina and this impact is exacerbated in drought conditions [43,44]. Further experiments in the field are underway to confirm this on a larger scale, and if true, silicon content could be manipulated to improve pest management. The temptation of using more agrochemicals to protect new biofuel sugarcane crops Even though the consumption of pesticides is relatively important, sugarcane is not a highly treated plots crop compared to other commodities (coffee, cotton, corn, soybean, etc.). The dense growth form of sugarcane limits insecticide effectiveness as do the endophagous habits of many of the key pests. Nonetheless some countries, notably South Africa, USA and Australia continue to apply insecticides to control major pests Current Opinion in Environmental Sustainability 2011, 3:81–89 86 Terrestrial systems [16,45,46]. This has led to significant environmental issues. In Australia, the proximity of sugarcane areas to the Great Barrier Reef World Heritage site has increased runoff pollution risk and led to strict regulations for the use of pesticides and fertilisers there [47]. In developing countries (particularly in Africa) and where agrochemical use is unsustainable and poorly regulated broad scale insecticides are still applied over large areas using ultra light planes or helicopters. This can induce insecticide resistance, outbreaks of secondary pests and destruction of natural enemy communities. As sugarcane industries, driven by overseas or international private companies, expand to meet the ‘biofuel’ demands, regulations and the science needed to underpin them will be critical to maximise production and pest control while minimising environmental harm. Varietal resistance to sugarcane pests and GM sugarcane varieties Use of conventional (non-GM) pest or disease resistant varieties is a major component of the IPM in sugarcane ecosystems but if recommendations for their use are not followed the risk of elevated pest pressure will remain [48–50]. New pest resistant varieties will remain part of the industry devoted to bioenergy production. However, ‘high fibre’ varieties are being developed for biofuel production and it is not known yet how these will effect pest performance particularly stem-borers. Screening such varieties in the field against a range of pest types might show if higher proportion of cellulose, hemicelluloses and lignins will influence pest abundance. Similarly ‘high sucrose’ varieties also currently under development are also likely to influence pest dynamics as it is known that sweet varieties are generally more susceptible to stem-borers. There is a need to directly consider the pest consequences of any new varieties and whether pest resistance can be an active parallel component of variety development. The use of genetically modified (GM) sugarcane has been identified as a future strategy for the expansion of sustainable sugarcane production [51]. The associated risks; capacity and public concerns about GM based sugar products entering the human food chain, biodiversity impacts, capacity for GM cane to escape and invade ecosystems beyond production systems or transfer the genes to closely related species have also been considered [51]. More importantly here the likely development of pest resistance to transgenic crops represents a significant threat to the large scale adoption of these cultivars [52,53]. The direct and indirect impacts GM varieties may have on the dynamics of the pests and their associated natural enemies will need to be understood. This is especially important for existing successful biological control strategies where volatiles emitted by the host plant following a pest attack play an important role. Research on new traits to be incorporated into sugarcane Current Opinion in Environmental Sustainability 2011, 3:81–89 varieties for pest particularly stemborer resistance is not yet complete [54]. GM sugarcane is likely to offer significant benefits for non-food commodity options for the industry, but will also generate significant acceptability risks for sugar production as a food additive. This conflict will also play out as it has for canola where there are real problems for cross contamination between production supply chains. As transgenic sugarcane varieties have not yet been commercialised we need to learn from other industries where GM varieties are under production (e.g. in maize, canola, cotton and soybean crops). Lessons and research avenues for sugarcane pest management: towards an areawide ecologically based approach Conventional Integrated Pest Management (IPM) systems have focussed on insect-plant interactions and cultural practices, biological control and host plant resistance characteristics to minimise pesticide use at the field/farm scale. Despite considerable progress in pest control, scientists are increasingly demonstrating the need to broaden conventional pest management systems by including a landscape component. This is mainly because insect population dynamics operate at a regional scale (metapopulation concept), which is particularly true with not only polyphagous pests and/or invasive species, but also their antagonists. To illustrate this, Mark D. Hunter [32] argued: ‘As insect ecologists, we are obligated to understand the processes that influence the abundance, richness and diversity of insects in fragmented landscapes. As pest managers, we need to know how the architecture of landscapes influences pest population dynamics and their interactions with natural enemies and agents of control. As conservation biologists, we must develop strategies to maintain focal insect species, faunal diversity and the trophic interactions that drive key ecosystem processes’. This provides the basis for future research to implement an ecological and area-wide pest management for future sugarcane production systems within multi-use landscapes. Mixing agronomy and ecology (‘agroecology’) using multi-disciplinary knowledge of crop–pest–natural enemy relationships in the ecosystem integrates multiple practices that minimise impact on natural processes [55]. Areawide pest management has increased dramatically over the past decade thanks to the development of remote sensing and Geographic Information Systems (GIS). These tools can generate maps of infestations (based on pest spectral signatures) combined with other map layers to localise high risk areas and therefore provide useful prediction systems for smart application of a management response [56]. A biosecurity component can be added to this to ensure rapid identification of new pests using new technologies (e.g. barcoding, remote microscopy, and in field diagnostic tests), new pest risk assessment and appropriate surveillance and cost-shared response in conjunction with government agencies. www.sciencedirect.com New pest threats for sugarcane in the new bioeconomy and how to manage them Goebel and Sallam 87 Summary and conclusions The rise of bioenergy production has the potential to revolutionise the sugarcane industry from its days as a low value crop when viability hung of the international price of sugar. The versatility and productivity of sugarcane will continue to support agriculture through multiple energy products for developing, emerging and developed economies. In this context, the International Sugar Organisation (ISO) predicts a rapid expansion of new sugarcane areas in almost all producing countries. Pest management problems in this industry are however set to get worse. The destruction of natural habitat to create new sugarcane areas, intensive agronomic practices and lack of naturally occurring enemies are key drivers to pest outbreaks. Vegetation clearance even on marginal lands continues unabated in developing countries in the need to achieve economic growth. The risks are high and need urgent assessment [57]. The industry needs precision agriculture to link management to the spatial distribution of pest outbreaks at large scales and allow early warning pests predictions. Ecologically based solutions combined with creative science-based landscape and area-wide management strategies will be required to reduce pest pressure regardless the production focus (sugar, ethanol or other by-products). Maintaining beneficial arthropods in the sugarcane landscape via natural refuges will be a key part of any strategy. Changing farming practices that ignore the implications for pest dynamics will compromise this industry. The change from sugar or fibre production will have implications for the tri-trophic interactions between crop, pests and natural enemies. New pest incursions will increasingly threaten the expansion of sugarcane production areas in new regions or countries, because of increased trade and poor biosecurity measures in many developing countries. These industry changes are generating key challenges for pest management that will require scientists, agronomists and producers to work together. Acknowledgements The results and conclusions presented here are part of outcomes from two current projects on sugarcane pest management funded by the Australian Center of International Agricultural Research (project Hort/2006/147) and Europe through the Marie Curie International Outgoing Fellowship (Project Ecogrubs 235862, Framework program 7). We thank our research colleagues from BSES Limited and CIRAD for their useful inputs and comments on this manuscript. The OECD Cooperative Research Programme provided support for the authors to attend a Biosecurity in the New Bioeconomy summit organised by CSIRO in Canberra Australia from 17 to 21 November 2009. References and recommended reading Papers of particular interest, published within the period of review, have been highlighted as: of special interest of outstanding interest 1. Botha FC: Future prospects. In Genetics, Genomics and Breeding of Sugarcane, vol 31. Edited by Henri R, Kole C. Science Publishers; 2010:249-264. www.sciencedirect.com 2. BNDES: Sugarcane-Based Bioethanol, Energy for Sustainable Development. 1st edition. Rio de Janeiro, Brazil: BNDES and CGEE Coordination; 2008. This book gives unprecedented mapping of the ethanol sector in Brazil and vast amount of information about future of this bioenergy for sustainable development. 3. 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He argues that any change in the way that humans appropriate plant biomass for biofuel production has immense implications and he concludes that entomologists have a unique opportunity to examine these varied implications. 32. Tscharntke T, Brandl R: Plant-Insect interactions in fragmented landscapes. Annu Rev Entomol 2004, 49:405-430. 33. Hunter MD: Landscape structure, habitat fragmentation, and the ecology of insects. Agric Forest Entomol 2002, 4:59-166. 34. Ricci B, Franck P, Toulon JF, Bouvier JC, Sauphanor B, Lavigne C: The influence of landscape on insect pest dynamics: as case study in southeastern France. Landscape Ecol 2009, 24:337-349. The authors found that the number of codling moths (Cydia pomonella) depended not only on local orchard characteristics but also on the characteristics of the surrounding landscape (hedgerows, abandoned orchards) despite intense control of local populations by insecticides. Current Opinion in Environmental Sustainability 2011, 3:81–89 37. 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Today more attention is paid across the world on the use of silicon (calcium silicate) in insect pest management and scientific papers on this topic are on the increase. The authors have conducted a remarkable work in South Africa on the effect of silicon on the stalk borer Eldana saccharina [44]. 44. Kvedaras OL, Keeping MG, Goebel FR, Byrne M: Water stress augments silicon-mediated resistance of susceptible sugarcane cultivars synergy in resistance of sugarcane cultivars to the Stalk Borer, Eldana saccharina Walker (Lepidoptera: Pyralidae). Bull Entomol Res 2007, 97:175-183. 45. Leslie GW, Moodley S: Progress in the use of insecticides for the control of the sugarcane thrips Fulmekiola serrata (Kobus) (Thysanoptera: Thripidae) in South Africa. Proc S Afr Sug Technol Ass 2009, 82:437-440. 46. White WH, Viator RP, Dufrene EO, Dalley CD, Richard EP, Tew TL: Re-evaluation of sugarcane borer (Lepidotera: Crambidae) bioeconomics in Louisiana. Crop Prot 2008, 27:1256-1261. 47. 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Tabashnik BE, Gassmann AJ, Crowder DW, Carrie`re Y: Insect resistance to Bt crops: evidence versus theory. Nat Biotechnol 2008, 26:199-202 doi: 10.1038/nbt1382. Can evolution of insect resistance threaten the continued success of transgenic crops producing Bacillus thuringiensis (Bt) toxins that kill pests? The answer is yes. From an analysis of more than a decade of global monitoring, Bruce Tabashnik and his team reveals that the frequency of resistance alleles to Bt toxin Cry1Ac has increased substan- www.sciencedirect.com tially in some field populations of Helicoverpa zea, a cotton bollworm. Field-evolved resistance in pest population should continue with the intensive planting of Bt cotton. 54. Craveiro KI, Gomes Ju´nior JE, Silva MC, Macedo LL, Lucena WA, Silva MS, de Souza Ju´nior JD, Oliveira GR, de Magalha˜es MT, Santiago AD et al.: Variant Cry1Ia toxins generated by DNA shuffling are active against sugarcane giant borer. J Biotechnol 2009, 145:215-221. 55. 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