Connecting scales: Achieving in‐field pest control from areawide and landscape ecology studies

Areawide management has a long history of achieving solutions that target pests, however, there has been little focus on the areawide management of arthropod natural enemies. Landscape ecology studies that show a positive relationship between natural enemy abundance and habitat diversity demonstrate landscape‐dependent pest suppression, but have not yet clearly linked their findings to pest management or to the suite of pests associated with crops that require control. Instead the focus has often been on model systems of single pest species and their natural enemies. We suggest that management actions to capture pest control from natural enemies may be forth coming if: (i) the suite of response and predictor variables focus on pest complexes and specific management actions; (ii) the contribution of “the landscape” is identified by assessing the timing and numbers of natural enemies immigrating and emigrating to and from the target crop, as well as pests; and (iii) pest control thresholds aligned with crop development stages are the benchmark to measure impact of natural enemies on pests, in turn allowing for comparison between study regions, and generalizations. To achieve pest control we will need to incorporate what has been learned from an ecological understanding of model pest and natural enemy systems and integrate areawide landscape management with in‐field pest management.     

Comparison of pollinators and natural enemies: a meta‐analysis of landscape and local effects on abundance and richness in crops

To manage agroecosystems for multiple ecosystem services, we need to know whether the management of one service has positive, negative, or no effects on other services. We do not yet have data on the interactions between pollination and pest‐control services. However, we do have data on the distributions of pollinators and natural enemies in agroecosystems. Therefore, we compared these two groups of ecosystem service providers, to see if the management of farms and agricultural landscapes might have similar effects on the abundance and richness of both. In a meta‐analysis, we compared 46 studies that sampled bees, predatory beetles, parasitic wasps, and spiders in fields, orchards, or vineyards of food crops. These studies used the proximity or proportion of non‐crop or natural habitats in the landscapes surrounding these crops (a measure of landscape complexity), or the proximity or diversity of non‐crop plants in the margins of these crops (a measure of local complexity), to explain the abundance or richness of these beneficial arthropods. Compositional complexity at both landscape and local scales had positive effects on both pollinators and natural enemies, but different effects on different taxa. Effects on bees and spiders were significantly positive, but effects on parasitoids and predatory beetles (mostly Carabidae and Staphylinidae) were inconclusive. Landscape complexity had significantly stronger effects on bees than it did on predatory beetles and significantly stronger effects in non‐woody rather than in woody crops. Effects on richness were significantly stronger than effects on abundance, but possibly only for spiders. This abundance‐richness difference might be caused by differences between generalists and specialists, or between arthropods that depend on non‐crop habitats (ecotone species and dispersers) and those that do not (cultural species). We call this the ‘specialist‐generalist’ or ‘cultural difference’ mechanism. If complexity has stronger effects on richness than abundance, it might have stronger effects on the stability than the magnitude of these arthropod‐mediated ecosystem services. We conclude that some pollinators and natural enemies seem to have compatible responses to complexity, and it might be possible to manage agroecosystems for the benefit of both. However, too few studies have compared the two, and so we cannot yet conclude that there are no negative interactions between pollinators and natural enemies, and no trade‐offs between pollination and pest‐control services. Therefore, we suggest a framework for future research to bridge these gaps in our knowledge.     

Conservation biological control and enemy diversity on a landscape scale

Conservation biological control in agroecosystems requires a landscape management perspective, because most arthropod species experience their habitat at spatial scales beyond the plot level, and there is spillover of natural enemies across the crop–noncrop interface. The species pool in the surrounding landscape and the distance of crop from natural habitat are important for the conservation of enemy diversity and, in particular, the conservation of poorly-dispersing and specialized enemies. Hence, structurally complex landscapes with high habitat connectivity may enhance the probability of pest regulation. In contrast, generalist and highly vagile enemies may even profit from the high primary productivity of crops at a landscape scale and their abundance may partly compensate for losses in enemy diversity. Conservation biological control also needs a multitrophic perspective. For example, entomopathogenic fungi, plant pathogens and endophytes as well as below- and above-ground microorganisms are known to influence pest-enemy interactions in ways that vary across spatiotemporal scales. Enemy distribution in agricultural landscapes is determined by beta diversity among patches. The diversity needed for conservation biological control may occur where patch heterogeneity at larger spatial scales is high. However, enemy communities in managed systems are more similar across space and time than those in natural systems, emphasizing the importance of natural habitat for a spillover of diverse enemies. According to the insurance hypothesis, species richness can buffer against spatiotemporal disturbances, thereby insuring functioning in changing environments. Seemingly redundant enemy species may become important under global change. Complex landscapes characterized by highly connected crop–noncrop mosaics may be best for long-term conservation biological control and sustainable crop production, but experimental evidence for detailed recommendations to design the composition and configuration of agricultural landscapes that maintain a diversity of generalist and specialist natural enemies is still needed.     

Adaptive defense of pests and switching predation can improve biological control by multiple natural enemies

One of the most important questions in biological control is whether multiple natural enemies can provide greater suppression of agricultural pests than a single best enemy. Intraguild predation (IGP) among natural enemies has often been invoked to explain failure of biological control by multiple enemies, and classical theoretical studies on IGP have supported this view. However, empirical studies are inconclusive and have yielded both positive and negative results. We extend classical models by considering anti-predator behavior of pests and diet switching of omnivorous natural enemies, and examine their effects on pest control. We assume that the pest can adaptively allocate effort toward the specific defense against each predator, and that the omnivorous natural enemy can consume disproportionately more of the relatively abundant prey (switching predation) by type III functional responses to prey items. The model predicts that adaptive defense augments pests but favors introduction of multiple natural enemies for controlling pests if IGP is weak. In contrast, switching predation does not make pest control by multiple natural enemies advantageous as in classical studies, in the absence of adaptive defense. However, switching predation reduces the necessity of defense by the pest against the omnivore and offsets the effect of adaptive defense. Thus, it makes the introduction of multiple natural enemies advantageous for pest control when the pest employs adaptive defense even if IGP is strong. These results suggest that types and combinations of behavior of prey and predators may greatly affect qualitative outcomes of biological control by multiple natural enemies.     

Organic farming expansion drives natural enemy abundance but not diversity in vineyard‐dominated landscapes

Organic farming is seen as a prototype of ecological intensification potentially able to conciliate crop productivity and biodiversity conservation in agricultural landscapes. However, how natural enemies, an important functional group supporting pest control services, respond to organic farming at different scales and in different landscape contexts remain unclear. Using a hierarchical design within a vineyard‐dominated region located in southwestern France, we examine the independent effects of organic farming and semi‐natural habitats at the local and landscape scales on natural enemies. We show that the proportion of organic farming is a stronger driver of species abundance than the proportion of semi‐natural habitats and is an important facet of landscape heterogeneity shaping natural enemy assemblages. Although our study highlights a strong taxonomic group‐dependency about the effect of organic farming, organic farming benefits to dominant species while rare species occur at the same frequency in the two farming systems. Independently of farming systems, enhancing field age, reducing crop productivity, soil tillage intensity, and pesticide use are key management options to increase natural enemy biodiversity. Our study indicates that policies promoting the expansion of organic farming will benefit more to ecological intensification strategies seeking to enhance ecosystem services than to biodiversity conservation.     

Carbon dioxide effects on stomatal responses to the environment and water use by crops under field conditions

The structural complexity of habitats has been espoused as an important factor influencing natural-enemy abundance and food-web dynamics in invertebrate-based communities, but a rigorous synthesis of published studies has not heretofore been conducted. We performed a meta-analytical synthesis of the density response of natural enemies (invertebrate predators and parasitoids) to experimental increases and decreases in the structural complexity of their habitats using data from 43 published studies, reporting 62 independent taxa. Studies varied in structural complexity at two spatial scales (habitat and within-plant architecture) and comprised a diverse array of natural-enemy taxa (natural-enemy assemblage at large, the entire spider assemblage, hunting spiders, web-building spiders, mites, hemipterans, coccinellid beetles, carabid beetles, ants, and parasitoids). For all taxa combined, increasing habitat structure resulted in a large and significant increase in natural enemy abundance. Similarly, decreasing habitat structure significantly diminished natural enemy abundance. Separate meta-analyses at two spatial scales (habitat and within-plant architecture) found that increasing habitat complexity resulted in significant increases in abundance. In particular, manipulating levels of detritus at the habitat spatial scale had the strongest effect on natural enemy abundance. In general, most guilds of natural enemies were significantly affected when the structural complexity of the habitat was altered. Seven of nine natural enemy guilds were more abundant under conditions of increased habitat complexity, with hunting spiders and web-building spiders showing the strongest response followed by hemipterans, mites, and parasitoids. Spiders in particular were negatively affected when habitat structure was simplified. The mechanisms underlying the accumulation of natural enemies in complex-structured habitats are poorly known. However, refuge from intraguild predation, more effective prey capture, and access to alternative resources (alternative prey, pollen, or nectar), are possible candidates. Our analysis was unable to confirm that predators aggregate in complex-structured habitats because prey (mostly herbivores) are more abundant there. The results of this meta-analysis support the view that basal resources mediate top-down impacts on herbivores, and provide encouragement that manipulations of habitat complexity can be made in agroecosystems that will enhance the effectiveness of the natural enemy complex for more effective pest suppression.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

农田景观格局对害虫天敌生态控害功能的调控作用

如何提升农田景观的生态服务功能是当前景观生态学和害虫防治学的前沿研究热点.基于区域农田景观格局可显著调节植物-植食性昆虫-天敌之间相互关系的理论基础,本文系统概括总结了农田景观格局及其变化对农田重要天敌多样性与生态控害功能的影响.从不同天敌类群的角度,分析了农田景观格局对捕食性天敌、寄生性天敌、有益微生物及其生态控害功能的调控作用.同时,对优化农田景观作物布局、采取合理的植被生境管理策略进行了展望.本文可为应用植被生境管理提升农田景观中天敌的生态系统服务功能提供参考,进一步促进区域生态农业响应"化学农药减量施用"的战略目标提供理论支撑.     

Effects of crop species richness on pest-natural enemy systems based on an experimental model system using a microlandscape

The relationship between crop richness and predator-prey interactions as they relate to pest-natural enemy systems is a very important topic in ecology and greatly affects biological control services. The effects of crop arrangement on predator-prey interactions have received much attention as the basis for pest population management. To explore the internal mechanisms and factors driving the relationship between crop richness and pest population management, we designed an experimental model system of a microlandscape that included 50 plots and five treatments. Each treatment had 10 repetitions in each year from 2007 to 2010. The results showed that the biomass of pests and their natural enemies increased with increasing crop biomass and decreased with decreasing crop biomass; however, the effects of plant biomass on the pest and natural enemy biomass were not significant. The relationship between adjacent trophic levels was significant (such as pests and their natural enemies or crops and pests), whereas non-adjacent trophic levels (crops and natural enemies) did not significantly interact with each other. The ratio of natural enemy/pest biomass was the highest in the areas of four crop species that had the best biological control service. Having either low or high crop species richness did not enhance the pest population management service and lead to loss of biological control. Although the resource concentration hypothesis was not well supported by our results, high crop species richness could suppress the pest population, indicating that crop species richness could enhance biological control services. These results could be applied in habitat management aimed at biological control, provide the theoretical basis for agricultural landscape design, and also suggest new methods for integrated pest management.     

Sustainable pest regulation in agricultural landscapes: a review on landscape composition, biodiversity and natural pest control

Agricultural intensification has resulted in a simplification of agricultural landscapes by the expansion of agricultural land, enlargement of field size and removal of non-crop habitat. These changes are considered to be an important cause of the rapid decline in farmland biodiversity, with the remaining biodiversity concentrated in field edges and non-crop habitats. The simplification of landscape composition and the decline of biodiversity may affect the functioning of natural pest control because non-crop habitats provide requisites for a broad spectrum of natural enemies, and the exchange of natural enemies between crop and non-crop habitats is likely to be diminished in landscapes dominated by arable cropland. In this review, we test the hypothesis that natural pest control is enhanced in complex patchy landscapes with a high proportion of non-crop habitats as compared to simple large-scale landscapes with little associated non-crop habitat. In 74% and 45% of the studies reviewed, respectively, natural enemy populations were higher and pest pressure lower in complex landscapes versus simple landscapes. Landscape-driven pest suppression may result in lower crop injury, although this has rarely been documented. Enhanced natural enemy activity was associated with herbaceous habitats in 80% of the cases (e.g. fallows, field margins), and somewhat less often with wooded habitats (71%) and landscape patchiness (70%). The similar contributions of these landscape factors suggest that all are equally important in enhancing natural enemy populations. We conclude that diversified landscapes hold most potential for the conservation of biodiversity and sustaining the pest control function.     

Landscape-scale forest cover increases the abundance of Drosophila suzukii and parasitoid wasps

Agricultural landscapes rich in natural and semi-natural habitats promote biodiversity and important ecosystem services for crops such as pest control. However, semi-natural habitats may fail to deliver these services if agricultural pests are disconnected from the available pool of natural enemies, as may be the case with invasive species. This study aimed to provide insights into the relationship between landscape complexity and the abundance of the recently established invasive pest species Drosophila suzukii and a group of natural enemies (parasitoid wasps), which contain species that parasitize D. suzukii in native and invaded ecosystems. The importance of landscape complexity was examined at two spatial scales. At the field scale, the response to introduction of wildflower strips was analysed, while the relationship with forest cover was assessed at the landscape scale. Half of the surveys were done next to blueberry crops (Vaccinium corymbosum), the other half was done in landscapes without fruit crops to examine effects of D. suzukii host presence. As expected, the number of observed parasitoid wasps increased with amount of forest surrounding the blueberry fields, but the number of D. suzukii individuals likewise increased with forest cover. Establishment of wildflower strips did not significantly affect the abundance of D. suzukii or parasitoid wasps and insect phenology was similar in landscapes with and without blueberry crops. This suggests that D. suzukii is enhanced by landscape complexity and is largely unlinked from the species group that, in its native range, hosts key natural enemies. Although management practices that rely on enhancing natural enemies through habitat manipulations can contribute to the long-term stability of agroecosystems and to control agricultural pests, other control measures may still be necessary in the short term to counteract the benefits obtained by D. suzukii from natural habitats.     

Assessing the impact of arthropod natural enemies on crop pests at the field scale

There are many reasons why it is important that we find ways to conserve, and better utilize natural enemies of invertebrate crop pests. Currently, measures of natural enemy impact are rarely incorporated into studies that purport to examine pest control. Most studies examine pest and natural enemy presence and/or abundance and then qualitatively infer impact. While this provides useful data to address a range of ecological questions, a measure of impact is critical for guiding pest management decision‐making. Often some very simple techniques can be used to obtain an estimate of natural enemy impact. We present examples of field‐based studies that have used cages, barriers to restrict natural enemy or prey movement, direct observation of natural enemy attack, and sentinel prey items to estimate mortality. The measure of natural enemy impact used in each study needs to be tailored to the needs of farmers and the specific pest problems they face. For example, the magnitude of mortality attributed to natural enemies may be less important than the timing and consistency of that mortality between seasons. Tailoring impact assessments will lead to research outcomes that do not simply provide general information about how to conserve natural enemies, but how to use these natural enemies as an integral part of decision‐making.     

Adaptive Release of Natural Enemies in a Pest-Natural Enemy System with Pesticide Resistance

Integrated pest management options such as combining chemical and biological control are optimal for combating pesticide resistance, but pose questions if a pest is to be controlled to extinction. These questions include (i) what is the relationship between the evolution of pesticide resistance and the number of natural enemies released? (ii) How does the cumulative number of natural enemies dying affect the number of natural enemies to be released? To address these questions, we developed two novel pest-natural enemy interaction models incorporating the evolution of pesticide resistance. We investigated the number of natural enemies to be released when threshold conditions for the extinction of the pest population in two different control tactics are reached. Our results show that the number of natural enemies to be released to ensure pest eradication in the presence of increasing pesticide resistance can be determined analytically and depends on the cumulative number of dead natural enemies before the next scheduled release time.     

Habitat linkages in conservation biological control: Lessons from the land–water interface

Terrestrial landscapes, including those with embedded agroecosystems, are a mosaic of cover types varying in size. Creating or maintaining habitats that support natural enemy populations to combat agricultural pests is the primary method of conservation biological control. Non-crop habitats can be managed in an attempt to maximize the exchange of natural enemies with adjacent agroecosystems with the expectation that they will suppress damaging pest outbreaks. Despite this goal, current habitat management relying on natural enemy spillover into crops has been unreliably effective at reducing pest abundance or increasing crop yield. Furthermore, the expansion and intensification of agriculture and changes in global climate patterns threaten the foundations of conservation biological control in future agroecosystems. However, the aquatic–terrestrial interface offers a natural boundary similar to the one between agroecosystems and their neighboring non-crop habitats that can provide useful insights to the challenges facing growers. Research of the exchanges between water and land suggests general biological and physical processes that govern the movement of organisms between disparate habitats. We propose that like aquatic insects moving from water to land, natural enemy dispersal from non-crop donor habitats into recipient crop patches on the landscape is a function of (1) the production of natural enemies in the source habitat which establishes the abundance of organisms that can disperse, (2) how and why mobile natural enemies disperse themselves into neighboring recipient habitats, and (3) the configuration of donor and recipient habitats on the landscape. We suggest that conservation biological control practitioners can focus on these main components of natural enemy production and dispersal to predict the effectiveness of conservation biological control measures and guide their adaptation to future global change.     

Habitat isolation affects plant–herbivore–enemy interactions on cherry trees

Understanding the interactions between herbivores and natural enemies in fragmented landscapes is essential for conservation biological control. Studies including multiple enemies affecting multiple herbivores, plant damage and growth are needed. Here, we separated independent effects of (1) isolation of cherry trees from woody habitat and (2) the amount of woody habitat in the surrounding landscape (500 m buffers) on interactions between different groups of herbivores with their natural enemies and resulting changes in the growth of young cherry trees. Most predatory arthropods declined with habitat isolation, except some aphid predators (ladybeetles and hoverflies). Herbivores either increased with isolation (herbivorous beetles) or showed no significant response (aphids). In contrast, the amount of woody habitat in the landscape was not relevant for herbivore–enemy interactions at the investigated scale. Plant growth was affected by bottom-up (nutrient availability) and top-down (aphid density) forces but did not change significantly with habitat amount or isolation. We conclude that herbivores can be released from natural enemies at isolated sites, in accordance with the hypothesis that habitat connectivity improves pest control. However, each herbivore group responded differently to the landscape context and had contrasting effects on the same host plant, demonstrating the difficulty to predict landscape effects on plant growth.     

Interactions Between Entomopathogenic Fungi and Other Natural Enemies: Implications for Biological Control

Pathogens and arthropod natural enemies may contribute to the suppression of insect pest populations either as individual species or as species complexes. However, because natural enemies of insects have evolved and function in a multitrophic context it is important to assess interactions within complexes of natural enemies if they are to be exploited effectively in pest management. Natural enemies can interact either synergistically/additively (e.g. enhanced transmission and dispersal of insect pathogens) or antagonistically (e.g. parasitism/infection, predation and competition). In this paper, studies assessing the potential interactions between insect and fungal natural enemies are reviewed. In general, these studies indicate the positive nature of the interactions between arthropod natural enemies and fungal pathogens with respect to the control of insect populations. More work is required to investigate further the many ways in which the natural enemy community interacts in the agroecosystem     

More pests but less pesticide applications: Ambivalent effect of landscape complexity on conservation biological control

In agricultural landscapes, the amount and organization of crops and semi-natural habitats (SNH) have the potential to promote a bundle of ecosystem services due to their influence on ecological community at multiple spatio-temporal scales. SNH are relatively undisturbed and are often source of complementary resources and refuges, therefore supporting more diverse and abundant natural pest enemies. However, the nexus of SNH proportion and organization with pest suppression is not trivial. It is thus crucial to understand how the behavior of pest and natural enemy species, the underlying landscape structure, and their interaction, may influence conservation biological control (CBC). Here, we develop a generative stochastic landscape model to simulate realistic agricultural landscape compositions and configurations of fields and linear elements. Generated landscapes are used as spatial support over which we simulate a spatially explicit predator-prey dynamic model. We find that increased SNH presence boosts predator populations by sustaining high predator density that regulates and keeps pest density below the pesticide application threshold. However, predator presence over all the landscape helps to stabilize the pest population by keeping it under this threshold, which tends to increase pest density at the landscape scale. In addition, the joint effect of SNH presence and predator dispersal ability among hedge and field interface results in a stronger pest regulation, which also limits pest growth. Considering properties of both fields and linear elements, such as local structure and geometric features, provides deeper insights for pest regulation; for example, hedge presence at crop field boundaries clearly strengthens CBC. Our results highlight that the integration of species behaviors and traits with landscape structure at multiple scales is necessary to provide useful insights for CBC.     

Coccinellid immigration to infested host patches influences suppression of Aphis glycines in soybean

Generalist natural enemies may be well adapted to annual crop systems in which pests and natural enemies re-colonize fields each year. In addition, for patchily-distributed pests, a natural enemy must disperse within a crop field to arrive at infested host patches. As they typically have longer generation times than their prey, theory suggests that generalist natural enemies need high immigration rates to and within fields to effectively suppress pest populations. The soybean aphid, Aphis glycines Matsumura, is a pest of an annual crop and is predominantly controlled by coccinellids. To test if rates of coccinellid arrival at aphid-infested patches are crucial for soybean aphid control, we experimentally varied coccinellid immigration to 1 m² soybean patches using selective barriers and measured effects on A. glycines populations. In a year with low ambient aphid pressure, naturally-occurring levels of coccinellid immigration to host patches were sufficient to suppress aphid populations, while decreasing coccinellid immigration rates resulted in large increases in soybean aphid populations within infested patches. Activity of other predators was low in this year, suggesting that most of the differences in aphid population growth were due to changes in coccinellid immigration. Alternatively, in a year in which alate aphids continually colonized plots, aphid suppression was incomplete and increased activity of other predatory taxa contributed to adult coccinellid predation of A. glycines. Our results suggest that in a system in which natural enemy populations cannot track pest populations through reproduction, immigration of natural enemies to infested patches can compensate and result in pest control.     

Coccinellid response to landscape composition and configuration

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Contrasting effects of natural habitat loss on generalist and specialist aphid natural enemies

The greater susceptibility of higher trophic levels to habitat loss has been demonstrated to disrupt important trophic interactions such as consumer control of prey populations. This pattern is predicted to break down for generalist species that can use matrix habitats, yet empirical studies comparing generalist and specialist enemy pressure in response to natural habitat loss are lacking. Here we examined the effects of landscape simplification resulting from habitat conversion to agriculture on nettles, Urtica dioica , their specialized aphid herbivore, Microlophium carnosum , and associated natural enemies that varied broadly in their degree of specialization. Both nettles and their specialized aphid herbivore were significantly more abundant in complex than simple landscapes. Different enemy groups showed contrasting responses. Aphid specialists (parasitic wasps and cecidomyiid midges) reached higher densities in complex than simple landscapes, and this effect was primarily related to shifts in local resource abundance (i.e. nettle aphid densities). In contrast, densities of generalists (coccinellid beetles and spiders) were significantly higher in simple landscapes, presumably due to spillover of generalists from surrounding cropland habitats. Natural enemy-prey ratios did not differ significantly across landscape types for specialist groups but were significantly higher in simple than complex landscapes for generalist groups, suggesting that enemy pressure on nettle aphids likely increases with landscape simplification. This was supported by our finding that aphid population growth rates were lower in simple than complex landscapes, and declined significantly with increasing coccinellid densities. Thus, in marked contrast to previous work, our results suggest that natural habitat loss may augment rather than disrupt consumer–prey interactions, and this will depend greatly on the degree of specialization of functionally dominant natural enemies.     

Biocontrol potential varies with changes in biofuel–crop plant communities and landscape perenniality

We examined the potential local‐ and landscape‐level impacts of different biofuel production systems on biocontrol, an important service provided by arthropod natural enemies. Specifically, we sampled natural enemies with sweep nets and measured predation of sentinel pest eggs in stands of corn, switchgrass and mixed prairie in Michigan and Wisconsin (total n=40 for natural enemy sampling, n=60 for egg predation), relating them to crop type, forb cover and diversity, and the composition and heterogeneity of the surrounding landscape. Grasslands with intermediate levels of forb cover and flower diversity supported two‐orders of magnitude more natural enemy biomass, fourfold more natural enemy families, and threefold greater rates of egg predation than corn. Data suggest this was in part due to a general increase in biomass, richness and predation in perennial grasslands compared with corn, combined with a positive effect of intermediate levels of forb cover and flower diversity. Specifically, natural enemy biomass and family richness showed hump‐shaped relationships to forb cover that peaked in sites with 5–25% forbs, while egg predation increased with floral diversity. At the landscape scale, both natural‐enemy biomass and egg predation increased with the area of forest in the landscape, and egg predation almost doubled as the area of herbaceous, perennial habitats within 1.5 km of study sites increased. Our results suggest that floristically diverse, perennial grasslands support diverse and abundant predator communities that contribute to natural pest suppression. In addition, large‐scale production of biofuel crops could positively or negatively affect biocontrol services in agricultural landscapes through associated changes in the area of perennial habitats. Biofuel landscapes that incorporate perennial grasslands could support a variety of beneficial organisms and ecosystem services in addition to producing biomass.