Pest Management Decisions Research Articles

The Role of Strategic Uncertainty in Area‐wide Pest Management Decisions of Florida Citrus Growers

AbstractWe elicit a measure of strategic uncertainty from growers by using an experimental game grounded on the theory of global games. This allows us to achieve the following: propose a mechanism for measuring strategic uncertainty aversion; compare growers' risk aversion to their strategic uncertainty aversion; explore how growers' strategic uncertainty aversion is affected by changes in group size and coordination requirement; and relate a strategic uncertainty aversion measure to growers' actual decisions to participate in an area‐wide pest management program. In our experimental setting, we found that when the coordination requirement for a successful outcome is low, most growers see the strategic uncertainty posed by human interaction as more favorable in terms of expected payoffs relative to a game against nature. In contrast, when the coordination requirement is high, most growers expect lower payoffs and choose to coordinate less. We also found evidence that growers' strong beliefs about neighbors not coordinating negatively impacted their choices to coordinate. Our measure of strategic uncertainty was also found to influence the likelihood of growers to actually coordinate sprays. Our findings help explain why participation in area‐wide pest management to control the vector of citrus greening across Florida has not been as widespread as expected; the strategic uncertainty involved in relying on neighbors has made many growers choose self‐reliance in spraying despite the lower payoff.

Influences of Stored Product Insect Movements on Integrated Pest Management Decisions.

Insect movement inside and outside grain bulks and processed products influences pest management decisions. Movement allows insects to find essential food resources, shelters (refuges), warmer and/or humid locations, mating and egg-laying sites, even when they are rare in fields, buildings, mills, warehouses, and inside grain masses. This review discussed the advantages and disadvantages of stored product insect movements, and the influence of insect mobility on some integrated pest management practices. Insect movement (1) results in clumped insect spatial distributions and thus makes large sample sizes necessary for monitoring; (2) makes trapping more efficient, but is influenced by many factors; (3) allows control methods to be effective, but requires pest management programs to be area-wide; (4) makes eradication of quarantine pests difficult and commodities are quickly re-infested; and (5) results in a diverse genetic pool and speeds the development of resistance to pesticides. Any element of an IPM approach should use the knowledge of insect movement. Reasons for the difficult interpretation of cryptic movement behaviours of insects were provided and future research areas were suggested.

Do field-level practices of Cambodian farmers prompt a pesticide lock-in?

Agronomic practices such as fertilizer application or seed rates have been known to affect rice pests and damage, but the evidence is often blurred in studies on pest management decisions and invisible in studies on pesticide lock-in. Combined agronomic practices and pesticide use may create technological lock-in, occurring when the combination has accumulated advantages over time which encourages its continued use, even if better options are available. We present results from a survey among farmers (N = 400) from five provinces in Cambodia. We asked about field-level, agronomic practices and applied a regression analysis to determine whether these practices affect pesticide application. Farmers from the selected provinces produce rice intensively, particularly those in provinces in the Mekong Delta where a percentage of farmers would aim for three crops per year.Cambodian farmers in the five sampled provinces rely on pesticides for pest control with an average of 2–5 applications each for herbicide and insecticide, and 1–6 applications of fungicide per season. Farmers from the Mekong Delta, particularly Prey Veng Province, made more pesticide applications. Interestingly, of nine agronomic practices tested, six were found to significantly correlate with no applications as in organic management recommendations, as well as misuse of pesticides. Varied combinations of agronomic practices including seed rate, crop establishment method, seed treatment, cultivating larger landholdings, irrigation through gravity irrigation system, and number of fertilizer applications predicted herbicide, insecticide and fungicide application. Interactions varied across wet and dry season. Pesticide use makes sense to farmers given a specific combination of agronomic practices. Therefore we argue that field-level agronomic practices contribute to pesticide lock-in as much as wider innovation system conditions such as trade and regulation of pesticides.These findings imply that addressing the pesticide lock-in to facilitate a shift to more sustainable practices, such as Integrated Pest Management, should not only aim at broader innovation systems or industry level changes. There are adjustments and fine-tuning of agronomic practices that also need to be made to wean farmers from pesticide reliance.

Biology and Management of the New Zealand Endemic Wheat Bug, Nysius huttoni (Hemiptera: Lygaeidae)

Abstract The wheat bug, Nysius huttoni White, mainly reported as a pest of wheat and forage brassicas, is native to New Zealand. This pest has been accidentally introduced into The Netherland and Belgium during apple exports from New Zealand. The bug population is abundant in open sparse vegetations and hot-dry habitats, and feeds on dropping seeds. It damages wheat grains during milk-ripe stage by piercing through the glumes into the developing grains that can reduce gluten protein and reduce baking quality. Bugs also suck phloem fluid from seedlings, which can reduce plant establishment in forage brassicas. Early scouting and field monitoring are suggested before making pest management decisions. Seed treatment with neonicotinoids, permethrin, and chlorpyrifos spray in the standing crops are chemical methods of management in New Zealand. These conventional synthetic pesticides have nontarget effects on human health, the environment, and biodiversity. However, preventive measures such as the use of less-susceptible cultivars, and using potential trap crops is other important pest management options. Alyssum (Lobularia maritima L. Desv. Brassicales: Brassicaceae) and wheat (Triticum aestivum L. Poales: Poaceae) are two potential trap crops of wheat bug. Kale (Brassica oleracea L.) cultivars, such as Corka and Regal, and wheat (Triticum aestivum) cultivars, such as Batten, Domino, and Oroua, are less-susceptible cultivars. Understanding the biology and ecology of the pest, and utilizing preventative pest management measures such as the use of trap crops and less-susceptible cultivars, and integrating these with ‘soft’ chemicals make a suitable integrated pest management strategy for this pest.

Influence of the public's perception, attitudes, and knowledge on the implementation of integrated pest management for household insect pests

AbstractHouseholds are mini‐ecosystems that provide a variety of conditions in which a variety of insect species can develop. Whether these insects are considered pests, largely depends on the perception, attitudes, and knowledge of the human inhabitants of the house. If considered unacceptable, residents can attempt to manage the insects themselves, or hire a professional. A pest management professional can provide a quick‐fix solution, often relying on the sole use of insecticides, or a sustainable solution through integrated pest management (IPM). In this review, it is discussed how the public's perception, attitudes, and knowledge affect the implementation of IPM in the household through the following steps: inspection, identification, establishment of a threshold level, pest control, and evaluation of effectiveness. Furthermore, recent and novel developments within the fields of inspection, identification, and pest control that allow to address pest infestations more effectively are described and their implementation in the household environment is discussed. In general, pest management in the household environment is reactive instead of pro‐active. The general public lacks the knowledge of the pest insects’ biology to identify the species, perform a proper inspection and identify causes of pest presence, as well as the knowledge of the available tools for monitoring and pest control. The percentage of individuals that seek professional aid in identification and pest control is relatively low. Moreover, the perception of and attitudes towards household insects generally result in low threshold levels. Current developments of methods for monitoring, identification, and control of insect pests in the household environment are promising, such as DNA barcoding, matrix‐assisted laser desorption/ionization time‐of‐flight and RNA interference. Efforts should be strengthened to alter the perception and attitude, and increase the knowledge of the non‐professional stakeholders, so that correct pest management decisions can be taken.

Density-invariant dispersion indices and fixed precision sequential sampling plans for the peach twig borer Anarsia lineatella (Lepidoptera: Gelechiidae)

Estimating the spatial dispersion of pest arthropods is crucial for the development of reliable sampling programs and one of the main components of integrated pest management. The natural spatial distribution of a population of a species may be random, uniform, or aggregated and can be so classified based on calculation of variance to mean relations and related dispersion indices. In this work some classical density-invariant dispersion indices and related regression models are used for the first time to quantify the spatial dispersion of an important peach pest Anarsia lineatella Zeller (Lepidoptera: Gelechiidae) and construct fixed precision sequential sampling schemes. Taylor's power law, Iwao's patchiness regression and Nachman's model were used to analyse the damage to peaches caused by A. lineatella. All three regression models fit the data well, although the results indicate that Iwao's patchiness model provides a better description of the relationship between variance and mean density. Taylor's b and Iwao's b regression indices were both significantly smaller than 1, indicating that the distribution of individuals was uniform rather than random or aggregated. According to Green's and Kuno's models, the minimum sample size at the precision level of 0.2 varies from 3 samples, when total population density is more than 3 larvae/sample, to 10 samples, when population density is between 1 and 2 larvae/sample. Kuno's fixed sampling plan indicates that a small number of samples (i.e., 3-10 branches with fruit) is sufficient to estimate the mean population density of A. lineatella larvae with a precision of 0.2. The Resampling for validation of sampling plans (RVSP) method confirmed that the average level of precision of the fixed sequential plans matched the desired precision in most cases. The sampling plan presented here provides a level understanding of A. lineatella spatial ecology suitable for pest management decisions.

Predicting the phenology of codling moth, Cydia pomonella, for sustainable pest management in Swiss apple orchards

AbstractThe effects of temperature on post‐diapause development, female lifespan, and reproduction of Cydia pomonella L. (Lepidoptera: Tortricidae) were studied under controlled conditions to determine the respective parameters for a temperature‐driven phenology model. Lower thermal thresholds of 10.0 and 9.7 °C and thermal constants of 417.2 and 427.7 degree days were established for post‐diapause development of females and males, respectively. Female lifespan was found to be 202.6 degree days on average, with a lower thermal threshold of 11.2 °C. Total fecundity was highest at 27.7 °C with an average of 241.9 eggs per female. Literature data were used to quantify the lower thermal thresholds and the thermal constants for eggs, larvae, and pupae. For validation, the model was run with weather data from 13 consecutive years and the output was compared with pheromone trap catches from 39 to 63 different orchards, depending on the year. The model proved to be a reliable and useful tool to forecast codling moth phenology under Swiss conditions not only for a whole growing season but also during several years with very variable weather conditions. Hence, it can be used to support apple growers in pest management decisions on the one hand and to predict changes in codling moth phenology with respect to climate change on the other.

Field evaluation of the susceptibility of mill and table olive varieties to egg‐laying of olive fly

AbstractThe susceptibility of 20 widely distributed mill and table olive varieties to Bactrocera oleae (Rossi) as affected by irrigation, and fruit diameter and oil content was evaluated in a 3‐year trial in Southern Spain. Bactrocera oleae was bivoltine life cycle in the experimental site, with significant differences among population size throughout the study. Even though the olive fruit fly damaged all varieties, significant differences in susceptibility were detected. Among the mill olive varieties “Nevadillo Blanco de Jaén” was the most susceptible, with average infestation levels ranging between 6.7% and 52.2% and between 10.3% and 69.2% under rainfed and irrigated conditions, respectively, and “Arbequina” was the least susceptible, with average infestation levels ranging between 0.6% and 12.7% and between 2.3% and 18.5% under rainfed and irrigated conditions, respectively. Among the table olive varieties, “Gordal Sevillana,” “Ascolana Tenera” and “Ocal” were the most susceptible (with average infestation levels reaching 39.7%, 36.5% and 33.3%, respectively), while “Callosina” was the least susceptible (with infestation levels of only 8.4%). Irrigation tended to promote both B. oleae infestation and its earlier occurrence compared to the rainfed condition. Even though the diameter and oil content were positively correlated with B. oleae fruit infestation (correlation coefficients ranged between 0.5 and 0.95), the present work reveals that other yet‐unknown factors may influence B. oleae oviposition preferences. The results of this study can be useful for breeding programmes to develop olive varieties resistant to B. oleae and provide key information for wide‐area olive fly pest management decisions.

Farmers’ perceptions of crop pest severity in Nigeria are associated with landscape, agronomic and socio-economic factors

Insect pests are a major cause of crop yield losses around the world and pest management plays a critical role in providing food security and farming income. This study links Nigerian farmers’ perceptions of pest severity to the landscape, agronomic, biophysical, and socio-economic context in which agricultural production takes place. A farm household survey was conducted during 2012–2013, collecting data on household characteristics, cropping systems, pest severity and pest management from 805 households in 12 states of Nigeria. Village characteristics and land use information were collected from an accompanying semi-structured village survey. Reported pest severity was negatively associated with the proportions of forest and unused land at the landscape scale. This finding suggests the existence of pest suppressive effects of a diverse landscape under African smallholder agriculture settings, confirming findings of more industrial and larger scale agroecosystems in the temperate zone. Application of fertilizers (chemical and manure) was negatively related to reported pest severity. Moreover, reported pest severity was lower in mixed-cropping systems than in mono-cropping systems, reinforcing the idea of a pest suppression benefit of diverse cropping systems. In conclusion, our findings suggest that the presence of non-crop areas in the landscape and the diversification of agroecosystems may be a viable strategy for smallholder farmers to manage pests with limited reliance of chemical insecticides in Nigeria, but that actual pest management decisions are influenced by a wide range of context-specific factors. The paper adds new evidence on the relationship between different production situation characteristics and pest severity for Nigeria, based on which policy implications are discussed.

Forest pests and their management in the Anthropocene

Forest managers are facing unprecedented challenges from rapid changes in forest pests. The core causes are changes in climate, land use, and global distributions of organisms. Due to invasions and range expansions by pests, and propagation of nonnative trees, managers are increasingly confronted with pest problems outside their range of experience. There is a need to adapt pest management practices more quickly and efficiently than is possible when managers work in isolation and mainly learn by trial and error. Here we identify general tactics for adaptation of forest pest management in the Anthropocene: growth and application of practical theory; improved biosecurity against future invasions; improved monitoring, prediction, and mitigation; increased sharing of knowledge among regions, countries, and continents; management plans that anticipate continuing change; improved assessment of costs, benefits, and risks of possible responses to new potential pests; assessment of system responses to pest management decisions so that subsequent decisions are increasingly better informed; and improved understanding of the couplings between forests, forest management, and socioeconomic systems. Examples of success in forest management can aid in other sectors (e.g., agriculture, pastoralism, fisheries, and water resources) that are similarly important to our environmental security and similarly challenged by global change.

To Spray or Not to Spray: A Decision Analysis of Coffee Berry Borer in Hawaii.

Integrated pest management strategies were adopted to combat the coffee berry borer (CBB) after its arrival in Hawaii in 2010. A decision tree framework is used to model the CBB integrated pest management recommendations, for potential use by growers and to assist in developing and evaluating management strategies and policies. The model focuses on pesticide spraying (spray/no spray) as the most significant pest management decision within each period over the entire crop season. The main result from the analysis suggests the most important parameter to maximize net benefit is to ensure a low initial infestation level. A second result looks at the impact of a subsidy for the cost of pesticides and shows a typical farmer receives a positive net benefit of $947.17. Sensitivity analysis of parameters checks the robustness of the model and further confirms the importance of a low initial infestation level vis-a-vis any level of subsidy. The use of a decision tree is shown to be an effective method for understanding integrated pest management strategies and solutions.

AuToDiDAC: Automated Tool for Disease Detection and Assessment for Cacao Black Pod Rot

Pest control strategies for crop diseases highly depend on visual inspection to assess the severity of the infection, which usually lead to inconsistencies: either over or under assessment. These inconsistencies could be attributed to the limitations of humans to perceive small differences. A more precise disease assessment is needed for better pest management decision, which will result to a more efficient utilization and allocation of resources for farm inputs. This translates to a better income for cacao farmers. This paper introduces a mobile application named AuToDiDAC or Automated Tool for Disease Detection and Assessment for Cacao Black Pod Rot (BPR). AuToDiDAC automatically detects, separates, and assesses the infection level of BPR in cacao through image processing and machine learning techniques. It gives the farmers the capacity to objectively monitor and report the infection level of the BPR compared to the common visual rating for plant disease level of infection. Pixel-level accuracy test of the tool showed an average of 84% accuracy on an independent test set of ten cacao pod images.

Physical Factors Influencing Orientation of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) to Food-Baited Traps

Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) is a serious pest of post-harvest durable stored food products for which traps are being developed as important tools for integrated pest management. This work addresses the effects of trap design, trap location, time of response, and light on the orientation of released groups of 7200 pedestrian T. putrescentiae to food-baited traps in experimental rooms maintained in full darkness at 28 °C and 70% RH. A standard trap made from a disposable Petri dish and four commercially produced stored-product pest traps of different designs were compared and evaluated for efficacy in trapping mites. Subsequent experiments evaluated the effect of trap placement, trapping duration, and light on mite capture. More mites were captured in the standard Petri dish trap when compared singly or side by side with four different commercial trap designs, so the standard trap was used in all other studies. Further experiments found that mites could be trapped 1 h after release at a distance of 2 m from the release point and at six meters from a mite source within 24 h. A greater number of mites were caught in traps placed along a wall than those away from a wall, demonstrating thigmotaxis to an edge. Traps at various heights on a shelf rack suggested that walking mites tended to be positively geotactic whether the source of mites was from the floor or from the top shelf at 1.8 m from the floor. More mites were caught in black-painted traps than in unpainted clear plastic traps in fully lighted rooms, suggesting that mites seek refuge from brightly lighted conditions. Light emitting diodes deployed with traps or assayed alone determined mites oriented positively to traps with violet or ultraviolet, with least preference to green, yellow, red and white lights. This research provides new information on orientation by T. putrescentiae that may help optimize trap designs and trap deployment for pest management decisions.

Comparison of bioassays to biotype grape phylloxera ("Daktulosphaira vitifoliae" Fitch) on "Vitis" ssp.

Grape phylloxera biotypes exist throughout viticultural regions causing substantial economic losses. In the past different biotyping assays were employed to determine host adaption and potential harm of phylloxera strains or field populations. Standardised and efficient laboratory assays are required to define biotypes according to their aggressivity as well as to make accurate pest management and quarantine decisions. We aim to provide information on the consistency of the three most commonly used assays to accurately identify grape phylloxera biotype. Two phylloxera biotypes (A, C) were tested on two host plants (rootstock 'Teleki 5C' V. berlandieri x V. riparia and V. vinifera 'Riesling') using three assays: Simple isolation chamber, excised root bioassay and aseptic dual culture bioassay. Insect number, life table and plant-based response parameters (root galling) were compared. The simple isolation chamber and aseptic dual culture bioassay produced consistent results, whereas the excised root bioassay did not. We demonstrated that biotype results depend on whether the technique used is tuberosity- or nodosity-based. Pest management decision based on a single assay may inaccurately assess the phylloxera aggressivity potential. Thus, we recommend using two assay types which allows comparison of both root gall types.

Sugarcane Aphid Spatial Distribution in Grain Sorghum Fields

Abstract. Sorghum, Sorghum bicolor (L.) Moench, is an important summer grain crop in the United States. In 2014, the U.S. produced 432 million bushels of sorghum valued at $1.67 billion on more than 2.43 million ha. The sugarcane aphid, Melanaphis sacchari (Zehntner), was discovered in damaging numbers in grain sorghum in Texas and Louisiana in 2013. The sugarcane aphid can be very damaging to sorghum grown for grain and forage and is capable of explosive population growth. An objective sampling plan based on knowledge of spatial distribution of the aphid in sorghum would be useful for pest management decision making. We sampled 94 commercial grain sorghum fields in five southern states during 2 years to obtain data that were used to assess several aspects of sugarcane aphid distribution within and among sorghum plants in commercial grain sorghum fields. There were frequently significant differences in number of aphids among upper and lower leaves in fields in each state. However, there were no consistent...

Maximizing Information Yield From Pheromone-Baited Monitoring Traps: Estimating Plume Reach, Trapping Radius, and Absolute Density of Cydia pomonella (Lepidoptera: Tortricidae) in Michigan Apple.

Novel methods of data analysis were used to interpret codling moth (Cydia pomonella) catch data from central-trap, multiple-release experiments using a standard codlemone-baited monitoring trap in commercial apple orchards not under mating disruption. The main objectives were to determine consistency and reliability for measures of: 1) the trapping radius, composed of the trap’s behaviorally effective plume reach and the maximum dispersive distance of a responder population; and 2) the proportion of the population present in the trapping area that is caught. Two moth release designs were used: 1) moth releases at regular intervals in the four cardinal directions, and 2) evenly distributed moth releases across entire approximately 18-ha orchard blocks using both high and low codling moth populations. For both release designs, at high populations, the mean proportion catch was 0.01, and for the even release of low populations, that value was approximately 0.02. Mean maximum dispersive distance for released codling moth males was approximately 260 m. Behaviorally effective plume reach for the standard codling moth trap was < 5 m, and total trapping area for a single trap was approximately 21 ha. These estimates were consistent across three growing seasons and are supported by extraordinarily high replication for this type of field experiment. Knowing the trapping area and mean proportion caught, catch number per single monitoring trap can be translated into absolute pest density using the equation: males per trapping area = catch per trapping area/proportion caught. Thus, catches of 1, 3, 10, and 30 codling moth males per trap translate to approximately 5, 14, 48, and 143 males/ha, respectively, and reflect equal densities of females, because the codling moth sex ratio is 1:1. Combined with life-table data on codling moth fecundity and mortality, along with data on crop yield per trapping area, this fundamental knowledge of how to interpret catch numbers will enable pest managers to make considerably more precise projections of damage and therefore more precise and reliable decisions on whether insecticide applications are justified. The principles and methods established here for estimating absolute codling moth density may be broadly applicable to pests generally and thereby could set a new standard for integrated pest management decisions based on trapping.

Outlook of Pyrethroid Insecticides for Pest Management in the Salinas Valley of California

Vegetable and strawberry (Fragaria × ananassa Duchesne ex Rozier) pest management involves intensive use of insecticides. Recently, pyrethroid insecticide residues toxic to benthic organisms (e.g., Hyalella azteca Saussure) were detected in the surface water of the Salinas Valley, California, resulting in the establishment of a Total Maximum Daily Load level for bifenthrin, cypermethrin, and lambda-cyhalothrin. Three discussion sessions and surveys were conducted during grower meetings held in Salinas, California, in 2016, regarding integrated pest management and critical use patterns of pyrethroid insecticides. Survey results were filtered to include only responses from qualified participants involved in pest management decisions on lettuce (Lactuca sativa L.), celery (Apium graveolens var. dulce Mill.), spinach (Spinacia oleracea L.), Brassica crops, and strawberry. Results indicated that there were many important crop-specific pests that were currently being controlled by pyrethroids, for example, western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae); Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae); cabbage looper, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae); and root maggots, Delia spp. (Diptera: Anthomyiidae). Participants suggested that the carbamate, methomyl, was the only effective alternative to pyrethroid insecticides for these pests. Although some lower risk controls may be useful on organic crops where there tends to be a higher tolerance for damage, lower risk controls will not be useful in conventional cropping systems until there is a higher tolerance for damage in the product. The survey indicated that insecticides selected for pest management were chosen based on cost, efficacy, low mammalian toxicity, and short reentry and preharvest intervals.

Validation of a geographic weighted regression analysis as a tool for area-wide integrated pest management programs for Ceratitis capitata Wiedemann (Diptera: Tephritidae) on Terceira Island, Azores

ABSTRACTExtrapolation from quantitative sampling to the surrounding areas is an essential feature of many aspects of real world applications in pest management decision-making. However, these decisions are only as good as the accuracy of the methods that provided the information. The problem of estimating Mediterranean fruit fly population densities from trap grids is a specific case. The efficiency of three methods to estimate fruit flies trapped per day values for non-sampled areas in Terceira Island is evaluated, the inverse distance weighted, ordinary Kriging and the geographic weighted regression (GWR). Each method has its own specificities and merits. The results demonstrate that the GWR method is capable of estimating hotspots for the next season and can be used to identify ecological corridors over a non-sampled area. The high spatial heterogeneity and topographical conditions present on Terceira Island may explain why a more mathematically complex method is more reliable than simpler methods for use in possible future wide-area control program for medfly.

Value of neonicotinoid seed treatments to US soybean farmers.

The benefits of neonicotinoid seed treatment to soybean farmers have received increased scrutiny. Rather than use data from small-plot experiments, this research uses survey data from 500 US farmers to estimate the benefit of neonicotinoid seed treatments to them. As seed treatment users, farmers are familiar with their benefits in the field and have economic incentives to only use them if they provide value. Of the surveyed farmers, 51% used insecticide seed treatments, averaging 87% of their soybean area. Farmers indicated that human and environmental safety is an important consideration affecting their pest management decisions and reported aphids as the most managed and important soybean pest. Asking farmers who used seed treatments to state how much value they provided gives an estimate of $US 28.04 ha-1 treated in 2013, net of seed treatment costs. Farmer-reported average yields provided an estimated average yield gain of 128.0 kg ha-1 treated in 2013, or about $US 42.20 ha-1 treated, net of seed treatment costs. These estimates using different data and methods are consistent and suggest the value of insecticide seed treatments to the US soybean farmers who used them in 2013 was around $US 28-42 ha-1 treated, net of seed treatment costs. © 2016 Society of Chemical Industry.

From species distributions to climate change adaptation: Knowledge gaps in managing invertebrate pests in broad-acre grain crops

Extensive research has shown that climate change will impact the distribution and outbreak potential of invertebrate pests in broad-acre crops. However, much less attention has been placed on translating these likely changes in pest outbreak frequency into practical management options for growers. Dryland grain production systems are generally predicted to be vulnerable to the effects of climate change. An initial step in understanding changes to outbreak potential of different pests is to describe the spatial distribution of different species and communities. Using a bioclimatic modelling approach, we demonstrate how general patterns of distribution for four major invertebrate pests of Australian dryland grain production systems are likely to be altered by climate change. While such models are useful for predicting the direct impacts of climate change on potential species distributions, they are less useful for assessing pest outbreak frequency from direct or indirect changes. In light of this, we explore different tools that can be used to support adaptive management by farmers to limit the impact of induced pest outbreaks. Primarily, research to increase available information of indirect impacts on the pest species and the communities they interact with, including their natural enemies, is required to extend models of pest outbreak potential. Further, incorporation of pests into global crop models combined with monitoring for existing pests and surveillance for new pests is critical for future pest management decision-making. For natural enemies, generalizations around the impact of climate change and flow on effects for pest control services need to be attempted now. The knowledge of potential management interventions is needed by farmers to support improved management decisions in the short-term, but in some cases will also facilitate adaption to climate change in the long-term.