Search

Many field studies have reported that natural habitats in the agricultural landscape are associated with increased predator abundance and/or decreased crop pest load. However, recently published meta-analyses have found mixed results, with natural habitats being associated with increased pest loads as often as decreased loads. We investigate possible reasons for these conflicting results using a mechanistic model that simulates the dynamics of a generalist, omnivorous predatory bug and a plant bug pest in a landscape consisting of a 1 km2 annual field crop monoculture bisected by a 60 m wide natural habitat strip. The model simulates the movement of adult predators in the landscape via both trivial movement and long-distance dispersal, along with the movement of energy and egg reserves carried by those predators. We simulate multiple scenarios varying the presence or absence of floral resources and alternate prey in the natural habitat and crop, and the presence or absence of overwintering refuges for the predator and pest insect in the natural habitat. Food resources provided to the predator by the natural habitat did not enhance natural control in adjacent crops. When the natural habitat served as an overwintering refuge for predators, natural control of pests was enhanced if food resources were available in the crop for those predators. Availability of alternate prey was more important to the predator than floral resources. Early-season crop pest loads were always increased when pest insects overwintered in the natural habitat, however early-season availability of pest insects enhanced natural control across the whole-season. Overall, crop pest loads were highly variable across simulation scenarios, reproducing the conflicting results from field research.

• Simulates thrips population dynamics in the presence of Orius predators. • Identifies suitable Orius release rates to control thrips under a target threshold. • Thrips oviposition rate and Orius egg survival rate are highly influential parameters. • Thrips handling time by Orius had little impact on both species populations' dynamics. The use of predatory insect species to control agricultural pests is a key aspect of Integrated Pest Management (IPM) that can help to reduce the use of chemical pesticides. A simulation model that captures the population dynamics and interactions of this predator–prey system can serve as a valuable IPM decision-support tool. However, such a simulation is challenging to construct due to the interactions between life stages of insect predators, prey and the crop plants. Frankliniella occidentalis (Western Flower Thrips, WFT) is an economically devastating global pest that damages diverse crops. Orius laevigatus is an effective and commercially available predator that controls WFT. We, therefore, developed a population dynamics simulation that models their interactions to better understand these insects' predator–prey dynamics in a strawberry crop. The model considers critical multi-stage predator–prey interaction, prey consumption reduction due to intraspecific competition, and the relationship between predation and oviposition rates of Orius. The simulation was structured using the boxcar train method, a stage-structured approach allowing insect populations to flow from one stage to the next over time. It was parameterised using data from existing literature. The results indicate the potential of the model to forecast the predator and prey species' population dynamics for different initial populations. A global sensitivity analysis identified that the daily oviposition rate of WFT and egg survival rate of Orius were the most significant parameters. The prey handling time of Orius on WFT did not significantly impact population variation. This model provides a useful tool for scenario exploration and assessment of the effects of Orius on WFT that can aid decision-making in IPM prior to implementation. [ABSTRACT FROM AUTHOR]

Highlights • A. biannulipes had a positive growth rate when feeding on D. porcellus larvae. • A. biannulipes exhibited a 'pin and jab' mode of predation. • A. biannulipes exhibited a mating behaviour that can be divided in four steps. • A. biannulipes reduced D. porcellus numbers after an 8 week laboratory trial. • A. biannulipes proves to be a biological agent control of D. porcellus. Abstract Stored yam chips are attacked by Dinoderus porcellus Lesne, which can cause significant losses. The predator Alloeocranum biannulipes Montr. and Sign. is a potential biological control agent of D. porcellus. The biology, predation and mating behaviour of A. biannulipes were investigated under laboratory conditions. Moreover, the regulatory effect of this predator on population dynamics of D. porcellus , and hence on yam chips losses, were evaluated under both laboratory and natural conditions. Female A. biannulipes laid on average 42.1 ± 6.8 eggs, which hatched some 4.3 ± 0.3 d after laying, with a hatching rate of 86%. A total of five nymphal stages were recorded with a total nymphal period of 28.2 ± 0.1 d, and a total developmental period of 32.4 ± 2.3 d. Female A. biannulipes lived longer (29.3 ± 1.3 d) than did the males (25.8 ± 4.1 d). Periods of pre-oviposition, oviposition, and post-oviposition were 12.8 ± 1.7, 10.5 ± 1.0 and 5.3 ± 0.5 d, respectively. Life‐table analysis revealed an intrinsic rate of increase 0.29 females/day and a gross reproductive rate of 28.38 females/female. The predator A. biannulipes exhibited a 'pin and jab' mode of predation, and its mating behaviour consisted in sequential actions (excitation and approach, riding over, copulation and post-copulation). Under laboratory conditions, A. biannulipes significantly reduced the numbers of D. porcellus and the weight loss of yam chips after 8 weeks at the initial density of 10 predator for 20 preys. Similar trends were observed under farmer storage conditions; there was a significant reduction in the D. porcellus population and in weight loss of yam chips as compared to the control treatment after 8 and 12 weeks for all tested density prey/predator. Therefore, our findings showed that A. biannulipes can be mass reared under laboratory conditions and has the potential to be an effective biological agent against D. porcellus in stored yam chips. [ABSTRACT FROM AUTHOR]

Highlights • Spiders are efficient predators in agroecosystems against pests. • Different non-prey foods significantly enhanced spiders' fitness. • Spiders actively selected the most beneficial non-prey foods. • Crops can offer alternative foods for spiders. • Agricultural management should promote practices that provide non-prey foods. Abstract Spiders are generalist predators adapted to consume a wide range of prey although their ability to exploit non-prey foods such as pollen, nectar, and honeydew has been referred but less studied. In this work, we investigated the effect of different non-prey food items (Glucose at 0.5 M; aphid honeydew; black scale honeydew; a mixture of glucose 0.5 M, phenylalanine 0.1 mM, proline 0.1 mM, and tryptophan 0.1 mM; honey at 10%, and pollen at 10%) on the survival of immature spiders of two functional groups represented by Haplodrassus rufipes (ground hunters) and Synema globosum (ambushers), and their feeding choices, in laboratory experiments. The overall survival of both species fed on non-prey foods significantly increased compared to individuals fed on water. The black-scale honeydew was the best food for H. rufipes increasing longevity up to 117 days. The highest survival reached by S. globosum was observed when fed on a mixture of glucose 0.5 M and three amino acids. When different non-prey food items were offered together, the exploring rate was significantly higher for H. rufipes than for S. globosum. H. rufipes chose to feed on honey whereas S. globosum chose the mixture treatment. The most chosen food items corresponded with those that provided the highest longevities in both species. Our results suggest that spiders could search, recognize and actively select the most beneficial non-prey food. Habitat management practices such as maintaining weed strips in the crop may provide these valuable supplementary food resources within agroecosystems contributing for biological pest control. [ABSTRACT FROM AUTHOR]

Pest management in protected sweet pepper crops mainly rely on biological control (BC) strategies. Recently, the zoophytophagous predatory mirids, Nesidiocoris tenuis , Macrolophus pygmaeus , and Dicyphus maroccanus , proved to be effective in the control of aphids on sweet pepper, for which the current biological control strategies have been meagre. The next step to integrate the possible use of these mirids in sweet pepper BC practices would be to ascertain their potential control on other sweet pepper pests. In this research, a comparative study to assess the establishment and the efficacy of N. tenuis , M. pygmaeus , and D. maroccanus on the two sweet pepper key pests; the thrips, Frankliniella occidentalis , and the whitefly, Bemisia tabaci was conducted. This study was carried out with two different temperature regimes, 20 °C and 27 °C, which simulated the mean temperatures registered in the two main crop cycles in Spain (the winter and summer planting period). Both, N. tenuis and M. pygmaeus were able to establish on sweet pepper and significantly reduced the number of F. occidentalis and B. tabaci adults, larvae and nymphs. Macrolophus pygmaeus had the highest density at 20 °C, whereas N. tenuis was more abundant at 27 °C. In contrast, D. maroccanus was less abundant under both temperatures studied; and did not reduce neither F. occidentalis nor B. tabaci infestations in this crop. None of the three mirids were observed to cause any damage to the pepper plant. The implications of these results applied to the use of mirids in sweet pepper crops are discussed. [ABSTRACT FROM AUTHOR]

Mealybugs (Hemiptera: Pseudococcidae) have spread throughout subtropical and tropical regions, causing severe losses to crop production that have prompted much interest in discovering effective biological agents against these pests. The Brazilian indigenous lacewing (Neuroptera: Chrysopidae) species Chrysoperla externa (Hagen) and Ceraeochrysa everes (Banks) were studied against two exotic mealybug species, Ferrisia dasylirii (Cockerell) and Pseudococcus jackbeardsleyi Gimpel & Miller. To assess the relative potential of these lacewing species as control agents against these two pests, we confined 1st-, 2nd-, and 3rd-instar lacewing larvae with 2nd- and 3rd-instar nymphs and adult female mealybugs to evaluate development, survival, reproduction and predation rate. Lacewing larvae at 2nd- and 3rd-instar preyed successfully on mealybugs of all ages, and second instar mealybug nymphs supported successful development of lacewing larvae irrespective of the predators’ age. However, 1st-instar lacewing larvae either failed to complete development or showed lower performance when fed only 3rd-instar or adult female of mealybugs of either species. Comparing the lacewing species, Ce. everes tended to produce more eggs, but showed delayed development and lower egg viability as compared to Ch. externa . Furthermore, in every case in which a significant difference in predation rate was detected, it was always superior for Ch. externa . Further studies to assess the establishment of these species and other lacewing species associated with these introduced mealybugs are reasonable to provide sustainable biological control. [ABSTRACT FROM AUTHOR]

Predatory mites of the family Phytoseiidae are important natural enemies of phytophagous mites and small insects. Phytoseiid mites often experience a variety of stresses brought about by changing or fluctuating environmental factors in the field or laboratory or during their commercial production. These factors include abiotic stressors such as extreme temperature and humidity, ultraviolet radiation, and pesticides, and biotic stressors such as cannibalism, intraguild predation, food shortage, and pathogens, all of which affect the biocontrol potential of phytoseiid mites. The extent to which an environmental stressor may affect the biocontrol efficacy of phytoseiid mites depends on the characteristics of the species and on other concurrent stresses. In this review, we discuss the effects of environmental stressors on various biological and ecological aspects of phytoseiid mites, such as development, survival, reproduction, and predation, and the mites’ adaptation strategies to these stressors. [ABSTRACT FROM AUTHOR]

The minute two-spotted ladybeetle, Diomus notescens Blackburn is a common predator of aphids and other pests in Australian agricultural crops, however little is known about the biology of D. notescens . The aim of this study was to provide information on the life cycle of this predator and improve our understanding of its biological control potential, particularly against one of the major pests of cotton, Aphis gossypii Glover. In laboratory experiments, juvenile development, prey consumption, as well as adult lifespan and fecundity were studied. Results from this study revealed that D. notescens could successfully complete development on A. gossypii , which at 25 °C required 21 days and during this period they each consume 129 ± 5.2 aphids. At 25 °C adult lifespan was 77 ± 9.6 days, with a mean daily prey consumption of 28 ± 1.8 aphids and a mean daily fecundity of 8 ± 0.5 eggs. Net reproductive rate was estimated as 187 ± 25.1 females and the intrinsic rate of increase was estimated as 0.14. Juvenile development was recorded at four constant temperatures (15, 21, 26 and 27 °C) and using a linear model, the lower threshold for D. notescens development was estimated to be 10 ± 0.6 °C with 285 ± 4.7 degree days required to complete development. A prey choice experiment studying predation rates revealed a strong preference for A. gossypii nymphs compared to Bemisia tabaci Gennadius eggs. [ABSTRACT FROM AUTHOR]

The Banks grass mite, Oligonychus pratensis (Banks) (Acari: Tetranychidae), is a serious pest in dates ( Phoenix dactylifera L.) in the New World. Currently O. pratensis is managed using the miticide, Savey, and alternative strategies are necessary to remove pressure from a single control method due to the risk of resistance evolution. For this purpose, studies are underway to develop biological control strategies using the predatory mite, Galendromus flumenis (Chant) (Acari: Phytoseiidae). The current study determined the consumption rate of G. flumenis at constant densities of O. pratensis eggs, larvae, protonymphs and deutonymphs, and defined the functional response of predator females. The predator consumed significantly more eggs than other prey stages, and displayed a type II functional response on all prey stages. The highest attack rate and shortest handling time were obtained for predators feeding on prey larvae and eggs, respectively. The proportions of prey consumed by G. flumenis were higher at lower densities for all stages of Banks grass mite, implying that G. flumenis should be more effective at suppressing Banks grass mite populations at lower densities. Therefore, in an augmentative release program, G. flumenis would need to be released early in the infestation. [ABSTRACT FROM AUTHOR]

Establishing effective methods of rearing natural enemies can facilitate basic and applied studies on their use in biological pest control. Insect predators of four genera ( Oligota , Stethorus , Scolothrips and Feltiella ) and predatory mites are important natural enemies of pest spider mites in agricultural crops. However, fewer laboratory studies have focused on insect predators due to the difficulty of their rearing. To establish a simple rearing method, we compared the rearing efficiency of four insect predator groups ( Oligota spp., Stethorus spp., Scolothrips takahashii and Feltiella acarisuga ) on potted komatsuna plants ( Brassica rapa ) infested with the two-spotted spider mite Tetranychus urticae , a new plant-prey combination for predator rearing in large containers, with that on potted bean plants infested with T. urticae . Significantly more Feltiella acarisuga and Stethorus spp. adults were obtained when offered T. urticae -infested komatsuna plants than infested lima bean or kidney bean plants ( Feltiella : 70, 9 and 0 adults, respectively; Stethorus : 72, 3 and 0 adults, respectively). More adults of S. takahashii and Oligota spp. were obtained on T. urticae -infested komatsuna than on infested lima bean ( Scolothrips : 181 and 27 adults, respectively; Oligota : 152 and 16 adults, respectively). Many individuals of all four predator groups such as larvae of F. acarisuga and Stethorus spp. were entrapped by the hooked trichomes on lima and kidney bean leaves, whereas no entrapped predators were observed on the komatsuna plants. These results show potted komatsuna plants infested with T. urticae to be suitable for efficient rearing of all four predator groups. [ABSTRACT FROM AUTHOR]

The combined release of species of generalist predators can enhance multiple pest control when the predators feed on different prey, but, in theory, predators may be excluded through predation on each other. This study evaluated the co-occurrence of the generalist predators Macrolop h us pygmaeus Rambur and Orius laevigatus (Fieber) and their control of two pests in a sweet pepper crop. Both predators consume pollen and nectar in sweet pepper flowers, prey on thrips and aphids, and O. laevigatus is an intraguild predator of M. pygmaeus . Observations in a commercial sweet pepper crop in a greenhouse with low densities of pests showed that the two predator species coexisted for 8 months. Moreover, their distributions in flowers suggested that they were neither attracted to each other, nor avoided or excluded each other. A greenhouse experiment showed that the predators together clearly controlled thrips and aphids better than each of them separately. Thrips control was significantly better in the presence of O. laevigatus and aphid control was significantly better in the presence of M. pygmaeus . Hence, combined inoculative releases of M. pygmaeus and O. laevigatus seem to be a good solution for controlling both thrips and aphids in greenhouse-grown sweet pepper. The predators are able to persist in one crop for a sufficiently long period and they complement each other in the control of both pests. This study also provides further evidence that intraguild predation does not necessarily have negative effects on biological control. [ABSTRACT FROM AUTHOR]

Highlights: [•] We examine the changes of δ13C and δ15N among crops, pests and predators. [•] δ13C or δ15N values of predators related to proportions of diets with equations. [•] Values of δ13C or δ15N can trace prey origins, proportions of diets. [•] Integrative values of δ13C and δ15N can trace feeding period of natural enemies. [•] Provide quantifying techniques for habitat management of natural enemies. [ABSTRACT FROM AUTHOR]

Highlights: [•] Beneficial insects may interact for resources such as prey and floral nectar. [•] Interactions may be additive or non-additive, potentially effecting biocontrol. [•] Volatile cues from hoverflies were avoided by female parasitoid wasps. [•] Female parasitoid wasp longevity was reduced by high hoverfly presence on flowers. [•] Responses of male wasps to hoverflies were more ambiguous. [ABSTRACT FROM AUTHOR]

Highlights: [•] A meridic diet was developed for Arma chinensis for 6 consecutive generations. [•] Nymphal development time prolonged and fecundity reduced. [•] Diet-reared adults lived longer than prey-fed adults. [•] A sex ratio shift in favor of males occurred in diet-reared populations. [•] The rearing method, combination of plant and artificial diet, was used here. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dengue mosquito eggs help perpetuate the disease through seasons. [•] Mosquitoes are attracted to lay eggs by tadpole cues. [•] Tadpoles of all five genera tested, are dengue mosquito egg predators. [•] Tadpoles live in various aquatic habitats that are often not accessible to fish. [•] Tadpoles are important for biological control of mosquitoes than previously thought. [ABSTRACT FROM AUTHOR]

Highlights: [•] Virus vector leafhopper moves from cereal fields to grassy habitats at harvest. [•] A dominant hunting spider in grassy margins has peak population density at that time. [•] In laboratory the leafhopper is among the favorable prey types for the spider. [•] When fed on a pure leafhopper diet spiders maintained their growth. [•] The spider is a potential natural enemy against the leafhopper. [Copyright &y& Elsevier]

Highlights: [•] The thrips Gynaikothrips ficorum and its predator Montandoniola confusa are associated and spreading alongside one another throughout Brazil. [•] M. confusa prey upon all thrips life stages and exhibits a type II functional response. [•] It is estimated ∼10-fold greater predation on eggs compared to larvae/prepupae and adult thrips. [Copyright &y& Elsevier]

Highlights: [•] We explored how releasing a generalist predatory mite impacted pest corn rootworms. [•] Unexpectedly, plots with mites had more rootworm larvae and higher root damage. [•] There were no effects on density of adult rootworms or plant biomass and yield. [•] Releasing mites likely altered trophic interactions among soil invertebrates. [•] Soil invertebrates can impact subterranean rootworm pests and root damage. [ABSTRACT FROM AUTHOR]

Abstract: Lambda-cyhalothrin is a pyrethroid insecticide widely used to control pests in various crop ecosystems, in which the lady beetle occurs naturally. Therefore, lady beetle populations are exposed to lambda-cyhalothrin sprays that may foster tolerance to this insecticide. This study was conducted to confirm the occurrence of resistance in the lady beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae) to lambda-cyhalothrin and to characterize the inheritance of resistance after eight progressive selection with insecticide dosages based on the LD50 determined for the F1 generation. Dose–mortality curves were determined for parental populations, F1 hybrids and backcross progenies. Parameters regarding the heritability of resistance to lambda-cyhalothrin in E. connexa allow estimating 10-fold increase in the initial LD50 after 54.5 generations of successive selections. The resistance of E. connexa to lambda-cyhalothrin was characterized as autosomally inherited and incompletely dominant, and influenced by a major gene with possible influence of secondary genes. Additionally, the resistance in E. connexa varies from functionally dominant to functionally recessive depending on the dose used. These findings indicate that insecticide resistance in E. connexa can be selected in the field as determined for field-collected individuals, and subsequently enhanced under laboratory conditions. Its characterization presented here is an important step toward linking biological and chemical control within pest management regarding the lady beetle and lambda-cyhalothrin targeting different pest groups. [Copyright &y& Elsevier]

Abstract: Generalist predators may disrupt or complement biological control by parasitoids. Past studies have examined how predators and parasitoids interact to affect aphid suppression, but more information is needed from other host taxa. Here, we explore the interactive effects of a spider (Cheiracanthium mildei) and a generalist parasitoid (Meteorus ictericus) on the light brown apple moth (Epiphyas postvittana), a recent introduction to North America. The spider negatively affected adult parasitoids in a field experiment, and reduced numbers of parasitized larvae in the laboratory. Nonetheless, the combined effects of parasitoids and spiders on larval mortality of the moth were additive. Percent parasitism was not affected by the presence of the spider in field or laboratory experiments, and results were similar when single or multiple larval instars of the moth were included. The spider’s lack of prey preference for unparasitized or parasitized larvae likely precluded any disruptive effects on parasitism. Results suggest that resident generalist parasitoids and predators can work in conjunction to hinder the invasion success of a novel herbivore prey species. [Copyright &y& Elsevier]

Abstract: Eriopis connexa (Germar) (Coleoptera: Coccinellidae) is an important predator with potential for biological control of insect pests. This research evaluated the development of E. connexa larvae fed on fresh eggs of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) without (T1) or with (T2) scales or one-day (T3) or six-month (T4) frozen, or newly-hatched larvae of S. frugiperda (T5). The percentage of E. connexa adults was higher when larvae feeding on fresh S. frugiperda eggs with or without scales, or one-day frozen eggs of this prey and lower with eggs of this Lepidoptera after frozen for six months or with newly-hatched larvae of S. frugiperda. Duration of the larval period of E. connexa was 15.7, 15.8, 16.0, 17.6, and 17.3days, respectively, with these diets. The high survival of E. connexa fed with eggs of S. frugiperda shows the potential use of this prey in the laboratory to maintain this natural enemy. [Copyright &y& Elsevier]

Abstract: Strawberry plants frequently suffer from simultaneous or sequential attacks of powdery mildew (Podosphaera aphanis) and the two-spotted spider mite (Tetranychus urticae), and for many years control of these two plant-damaging organisms have been achieved by use of sulfur and the predatory mite Phytoseiulus persimilis, respectively. Sulfur, predatory mites, and powdery mildew have long been studied separately regarding their impacts on spider mites, but knowledge of their combined influence in that context is also needed to aid integrated pest and disease management. Therefore, we conducted controlled laboratory experiments to study the main and the interaction effects of sulfur, P. persimilis, P. aphanis, and T. urticae in strawberry leaf disc bioassays. The results showed that the predatory mite, powdery mildew, and sulfur had additive effects on reducing egg number and population growth of T. urticae. Compared to the control, populations of T. urticae on the leaf discs were decreased by 83%, 76%, and 61% after 5days of treatment with sulfur+powdery mildew+predatory mites, mildew+predatory mites, and predatory mites alone, respectively. The survival and egg production of T. urticae females was affected to the greatest extent by P. persimilis, followed by powdery mildew. Residual sulfur had a short-term suppressive effect on T. urticae egg production but did not influence survival and reproduction of P. persimilis. If these findings also apply under field conditions, controlling powdery mildew will not reduce the need for spider mite control in strawberry, as has been suggested for other fruit crops. [Copyright &y& Elsevier]

Abstract: Conservation biological control (CBC) combines a diverse set of actions aiming to enhance pest regulation by the provision of pest natural enemies’ preservation in the crop environment. This is accomplished through appropriate implementation practices and the creation of infrastructures of non-crop vegetation. On most annual crops, omnivorous heteropteran predators comprise the main assemblage of native natural enemies. Their populations, when protected from pesticides, have shown a high potential in biological control. Aiming to promote their functioning in CBC, efforts targeted to modify the crop environment are focusing on the determination of their non-crop host plants that can support the predators’ persistence as well as the emigration of these predators to the nearby crops. Nonetheless, relatively few studies seek to collect essential and adequately verified data for the practical implementation of CBC approaches. In this review, the advances already developed are illustrated, the shortcomings are discussed and the future research needs are highlighted in an effort to intensify efforts for CBC developments on annual crops. [Copyright &y& Elsevier]

Abstract: The use of plant-feeding predators for biological pest control has traditionally been neglected, mainly due to the risk of them feeding on crop plants and causing economically significant damage. Yet, these predators offer advantages for biological pest control. They are mostly generalist predators that have an impact on several crop pests. They may also be able to establish on crops early in the growing season, when pests colonize them, and can remain on the target crop when prey is scarce. Therefore, management programs must seek to minimize risks while maximizing benefits. In vegetable crops, most of the literature on zoophytophagous predators has focused on four species: Dicyphus tamaninii, Dicyphus hesperus, Macrolophus pygmaeus and Nesidiocoris tenuis (Heteroptera, Miridae). The capacity of these species to produce crop damage in tomatoes varies. This damage has been related to relative predator-to-prey abundance, with damage increasing at high predator abundances and low prey densities. In this review, we analyze the use of these species in biological control programs and the associated benefits and risks. The differences in the damage caused by the four predatory species examined could not be attributed to either stylet morphology or saliva composition. However, feeding on specific plant structures where they may find the resources required for their development is what probably determines feeding damage. Understanding when and why these predators increase their feeding on plants or on certain plant parts is of crucial importance for integrating them in biological control programs. [Copyright &y& Elsevier]

Abstract: Perennial plants, such as willows, miscanthus, and hybrid poplars, are promising bioenergy crops while lowering atmospheric CO2. Increases in the acreage of perennial bioenergy crops will pose new challenges and opportunities for biological control. In this review, we suggest that zoophytophagous bugs could be expected to become increasingly important in biological control of arthropod pests in perennial bioenergy crops. The main reasons are: (1) perennial bioenergy crops provide suitable habitats for arboreal natural enemies like zoophytophagous bugs; (2) zoophytophagous bugs often increase in response to low disturbance frequencies; and (3) plant-feeding by zoophytophagous bugs will not likely affect plant biomass production in perennial crops. We review aspects of the biology of zoophytophagous bugs expected to be important in biological control of pests in perennial systems. We also present a predator–prey model investigating how alternative harvest methods affect biological control of herbivorous pests by zoophytophagous bugs in willow biomass plantations. Although there is good evidence that zoophytophagous bugs can provide pest control, more research is needed about factors affecting the dispersal and population dynamics of zoophytophagous bugs in agricultural landscapes. [Copyright &y& Elsevier]

Abstract: Heteropteran predators constitute an important component of predatory guilds in terrestrial and aquatic ecosystems. Most heteropteran species have generalist diets, and intraguild predation has been documented in most heteropteran families. Zoophytophagous species also frequently engage in intraguild interactions. An increase in extraguild prey density is often predicted to reduce intraguild predation between guild members by providing abundant alternate prey. However, an increase of extraguild prey density may also be associated with an increase in the density of intraguild predators, which could instead strengthen intraguild predation. Evaluating the combined effect of these potentially opposing influences on intraguild predation is difficult. Most studies have been carried out in the laboratory, using artificially simplified communities of predators and prey and employing spatial and temporal scales that may not reflect field conditions. We review experimental studies examining how extraguild prey density influences the intensity of intraguild predation and then report an observational case study examining the influence of extraguild prey density on the intensity of intraguild predation at larger spatial and temporal scales in unmanipulated cotton fields. Fields with more abundant extraguild prey (aphids, mites) were not associated with elevated densities of intraguild predators, and were strongly associated with increased survival of intraguild prey (lacewing larvae). In this system, the ability of extraguild prey to relax the intensity of intraguild predation, as previously documented in small-scale field experiments, also extends to the larger spatial and temporal scales of commercial agriculture. [Copyright &y& Elsevier]

Abstract: Reproductive ecology entails relating the physiology and behavior of an organism to its environment and the community in which it lives. Terrestrial predatory Heteroptera (including Anthocoridae, Geocoridae, Miridae, Nabidae, Pentatomidae, Phymatidae, and Reduviidae) display a wide range of reproductive ecologies. But in spite of this variability, a review of the literature reveals certain underlying trends that are useful in understanding how generalist predators function within their environments. First, the reproductive ecology of predatory bugs is inherently coupled to the physiology of the female and her eggs. Second, three population parameters are directly tied to reproduction (maturation rates, realized fecundity, and reproductive diapause) have great bearing on the rate of population increase and reproductive success of a predatory bug, but these three parameters fluctuate widely within and among species. The variables that affect these processes include the physiological status of the mother (mating status, age and size, and nutritional status), the abiotic environment in which she and her eggs live (temperature, photoperiod, water availability), and natural enemies that attack eggs and reproductive females. A final trend observed in the literature involves the hierarchy of events that must occur before a female finds a suitable oviposition site. Females all must locate preferred habitats, plants/substrates, and microsites in which to insert or deposit an egg, but they use a variety of tactics and cues in order to accomplish this, depending on their life history traits. Examining the factors that constrain and promote the reproductive potential of predatory Heteroptera will make biological control programs that center on them more reliable and sustainable. [Copyright &y& Elsevier]

Abstract: Deployment of genetically modified (GM), herbicide-tolerant corn may alter weed flora abundance and composition and may affect pests and their natural enemies. Among on-plant predators, Orius spp. are the prevalent group in Spain and were selected to study the impact of glyphosate use on predators. We also studied Nabis sp. which is commonly recorded on corn in the study area. For this, a 4-year study was conducted in NE Spain. Three different herbicide regimes were compared: two glyphosate (a broad-spectrum herbicide) treatments per season, no herbicide treatment, and one pre-emergence conventional treatment with selective herbicides against broadleaf and grassy weeds. Density of main arthropod herbivores and the above two predatory groups was recorded on plants. Differences between herbicide regimes were observed in the two functional groups studied, herbivores and heteropteran predators. The comparison of glyphosate-treated and untreated plots showed significant differences for both functional groups, but the differences between glyphosate-treated and conventionally treated plots for the two functional groups were lower. For Orius spp., annual density per plot was significantly correlated with annual density of leafhoppers and to a lesser extent, with aphids. Nabis sp. densities were never different between glyphosate-treated and conventionally treated plots, and Nabis sp. density showed no relation to any of the herbivores tested. We concluded that no significant changes in heteropteran predator densities may be expected from moderate alterations in weeds arising from the deployment of herbicide-tolerant corn varieties and that leafhoppers are probably the herbivore prey that most influences Orius spp. densities in corn in our study area. [Copyright &y& Elsevier]

Abstract: The citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), is a pest of citrus worldwide, and a major pest of satsuma mandarin (Citrus unshiu Marcovitch) in Alabama. This study was conducted to evaluate the potential of three commercially available predacious mite species (Acari: Phytoseiidae), Phytoseiulus persimilis Athias-Henriot, Galendromus occidentalis (Nesbitt), and Neoseiulus californicus (McGregor), as biological control agents of P. citri. The functional responses (at densities ranging from 2 to 150 P. citri immature per leaf disc arena) and prey-stage preferences (when offered varying ratios of P. citri eggs and nymphs) of the phytoseiids were investigated in laboratory experiments. All three species were modestly effective in regulating P. citri nymph density, but very few eggs were laid by each on the prey. Logistic regression analysis suggests a Type II (convex) functional response for all three species: the number of prey consumed increased with prey availability up to a maximum point after which it slowly began to decrease. The maximum daily predation was recorded at a prey density of 75 P. citri nymphs per arena for female P. persimilis and G. occidentalis, and at a density of 100 nymphs per arena for female N. californicus. Results from experiments on prey-stage preferences showed that all three phytoseiids preferred nymphs to eggs of P. citri. Food deprivation for up to 48h had no significant effect on the number of prey consumed or the prey-stage preferences of the phytoseiids. Among the three species, P. persimilis had the highest predation potential, in particular at high prey densities. These results are discussed in relation to the feeding habits and specialization of the phytoseiids and their potential for biological control of P. citri in citrus orchards. [Copyright &y& Elsevier]

Abstract: In this paper, we report the first evidence for the suppression of coconut mite Aceria guerreronis Keifer (Acari: Eriophyidae) populations by augmenting the natural population of the predatory mite, Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae) by an inundative release with laboratory-bred N. baraki. On each of five coconut mite infested palms in two plantations in the same agro-climatic zone of Sri Lanka, 10,000 laboratory-bred N. baraki was released once and the numbers of both N. baraki and coconut mite were assessed over a period of 6months. Irrespective of the plantation, release of N. baraki resulted in a significant increase in its population on released palms during the post-release period of 6months with a mean number of 8.99±1.03 per fruit compared to 6.19±0.80 per fruit on unreleased palms. A single release of N. baraki showed a highly significant positive impact on the coconut mite population in the released palms in both plantations. The mean numbers of coconut mites per fruit were 1264.77±139.07 and 1815±46 in the released and unreleased palms, respectively, during the sampling period. [Copyright &y& Elsevier]

Abstract: The annual occurrence and distribution of the predatory bugs Anthocoris nemorum and Anthocoris nemoralis between apple, pear and herbal vegetation, was assessed in three apple orchards in 2001, and in two apple and two pear orchards in 2002. In the laboratory anthocorid prey preference was assessed in two-choice experiments with key pests of apple and pear including pear psyllid, apple psyllid, green apple aphid, rosy apple aphid and red spider mites. Anthocorid predation behavior towards pear psyllids was assessed. Anthocorids were the dominant early season predatory bugs. A. nemorum dominated in apple, while A. nemoralis dominated in pear. A. nemorum was also common in herbal vegetation, especially in mid-summer. Anthocorid numbers were correlated with numbers of collembola, psyllids and aphids in apple, and with numbers of psyllids in pear. A. nemoralis preferred pear psyllid to green apple aphid, while A. nemorum preferred green apple aphid. Both species preferred psyllids to spider mites. The success rate of A. nemoralis in attacking pear psyllids was higher than that of A. nemorum. A. nemorum had two generations in both 2001 and 2002 proving that it can be bivoltine under Danish climate conditions. The mid-summer move by A. nemorum from trees to herbal vegetation suggests that herbal vegetation may maintain A. nemorum in orchards at times of low prey numbers in the trees. Habitat and prey preference trials both identify A. nemorum as a biological control agent of special importance in apple, whereas A. nemoralis is of importance in pear. [Copyright &y& Elsevier]

Abstract: Tetranychus evansi Baker and Pritchard, is a key pest of tomato in Africa. Surveys have been conducted in the last few years to search for predators associated with this pest in Brazil for introduction into Africa. Biological parameters of Phytoseiulus longipes Evans, one of the predators found in those surveys, were evaluated when it was exposed to different food items, including T. evansi, in laboratory tests. The predator had about the same oviposition rate on T. evansi and on Tetranychus urticae Koch; it did not oviposite when fed on pollen of Ricinus communis L. or Typha sp. When given the choice, the predators were found in higher proportions on leaflets infested with T. evansi than with T. urticae; on the former leaflets, they also laid more eggs. Full life table analysis indicated that the predator performed well on T. evansi and on T. urticae, although reproductive parameters were higher on the former prey. The results suggest that the Brazilian population of P. longipes has a good potential as a biological control agent of T. evansi. [Copyright &y& Elsevier]

Abstract: The development and reproductive capacity of Joppeicus paradoxus Puton (Hemiptera: Joppeicidae) reared on Tribolium confusum Jaquelin du Val (Coleoptera: Tenebrionidae) eggs, which is one of major pests of stored grain, were investigated at five constant temperatures (25, 28, 30, 32 and 34°C), 70–80% RH and a 16L–8D photoperiod. The duration of pre-adult (egg to adult) stage ranged from 60.2 days at 32°C to 142.9 days at 25°C. Emergence rates were more than 55.6% at 25–32°C, but only 27.2% at 34°C. Female lifetime fecundity was greatly reduced at 34°C, and reached a maximum at 30°C. Female longevity ranged from 72.5 days at 28°C to 118.5 days at 32°C. The net reproductive rate (R 0) and the intrinsic rate of natural increase (r m) were the highest at 30°C. It was estimated that the optimum temperature conditions for population increase of J. paradoxus, when fed with T. confusum eggs, lie around 30°C. [Copyright &y& Elsevier]

Abstract: Morphological defense traits of plants such as trichomes potentially compromise biological control in agroecosystems because they may hinder predation by natural enemies. To investigate whether plant trichomes hinder red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), as biological control agents in soybean, field and greenhouse experiments were conducted in which we manipulated fire ant density in plots of three soybean isolines varying in trichome density. Resulting treatment effects on the abundance of herbivores, other natural enemies, plant herbivory, and yield were assessed. Trichomes did not inhibit fire ants from foraging on plants in the field or in the greenhouse, and fire ant predation of herbivores in the field was actually greater on pubescent plants relative to glabrous plants. Consequently, fire ants more strongly reduced plant damage by herbivores on pubescent plants. This effect, however, did not translate into greater yield from pubescent plants at high fire ant densities. Intraguild predation by fire ants, in contrast, was weak, inconsistent, and did not vary with trichome density. Rather than hindering fire ant predation, therefore, soybean trichomes instead increased fire ant predation of herbivores resulting in enhanced tritrophic effects of fire ants on pubescent plants. This effect was likely the result of a functional response by fire ants to the greater abundance of caterpillar prey on pubescent plants. Given the ubiquity of lepidopteran herbivores and the functional response to prey shown by many generalist arthropod predators, a positive indirect effect of trichomes on predation by natural enemies might be more far more common than is currently appreciated. [Copyright &y& Elsevier]

We examined the ovipositional preference and larval to early adult performance of two generalist, predatory green lacewing species Chrysoperla comanche (Banks) and Chrysopa nigricornis Burmeister. Both of these predators are abundant in pecan trees (Carya illinoensis (Wagenh) K. Kock) in southern Arizona where two specialist aphids Monellia caryella (Fitch) and Melanocallis caryaefoliae (Davis) are found. Ovipositional preference was tested in a three-way choice experiment with pecan seedlings infested with one of the two aphid species or without aphids. Females of both green lacewing species showed a significant preference for ovipositing on plants bearing aphids, but only C. comanche distinguished between the two aphid species. Both aphid species were suitable for larval development and developmental time was not affected by aphid treatment. C. nigricornis pupae were significantly heavier when larvae were fed only M. caryaefoliae, but no difference in pupal weight was found for C. comanche. The pre-oviposition period was significantly longer for C. nigricornis females that were fed a mixture of the two aphid species during larval development compared with each aphid species alone. However, aphid diet did not affect the number of eggs laid by either species during the first five days of oviposition. [Copyright &y& Elsevier]

Macrolophus caliginosus (Wagner) is currently commercialized in Europe for the control of whiteflies in tomato greenhouses. Another mirid predator, Dicyphus tamaninii Wagner, spontaneously colonizes Mediterranean greenhouses. The impact of the presence of D. tamaninii on predation of the greenhouse whitefly (Trialeurodes vaporariorum Westwood) by M. caliginosus was investigated in the laboratory on tomato plants during four days. No significant interspecific competition was recorded between mirid nymphs and no significant intraguild predation was observed. Higher level of predation of the whitefly populations was achieved by D. tamaninii alone, than by M. caliginosus alone. Predation by the heterospecific combination (M. caliginosus + D. tamaninii) was similar to the results obtained by conspecific treatments. No intraspecific competition was recorded with D. tamaninii, nor with M. caliginosus. Finally, the distribution of whitefly predation on the plant by the mirids changed according to the predator treatment. The heterospecific combination of both mirids had a higher predation rate on lower leaves of the plant than monospecific combinations. Overall, the presence of D. tamaninii did not disrupt whitefly predation by M. caliginosus and could even increase the level of predation. [Copyright &y& Elsevier]