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In this study, the predatory mite

Agricultural intensification is affecting the biological control of insect pests, an important component for sustainable crop production. To understand the changing patterns of insect abundance within an agroecosystem, it is necessary to disentangle the trophic interactions between species, and metabarcoding is an excellent alternative to show them. In the Ebro Basin (NE Iberian Peninsula), agricultural landscapes are composed of a mosaic of crops scattered with natural and semi-natural habitats, where the presence of Orius spp., used as biocontrol agents, is well known. To shed light on their predatory role in this area, a previously developed metabarcoding multi-primer method has been used to study the arthropod and plant most frequently resources consumed by some field-collected Orius, sampled at different dates in a peach and an alfalfa adjacent crop. Their high-throughput sequencing (HTS) analysis showed the consumption of 15 arthropod and 12 plant taxa. Eight of them were consumed by O. laevigatus, six by O. majusculus and 23 by O. niger. The obtained results showed that HTS is a powerful tool in studies of trophic interactions in agroecosystems. Among the detected arthropods, other natural enemies were present, showing a certain degree of intraguild predation, which has been demonstrated by developing a new added strategy in the bioinformatic analysis. Detected plant consumption indicates that Orius forages on several plant species, showing their movement from them to the sampled crops. These plants could have a potential role in attracting or maintaining these predators in both crops in biological control strategies.

We assess the effects of changing land use and crop management on alfalfa insect abundance by comparing it in 50 alfalfa fields when they were inserted in landscapes with different proportions of arable crops and orchards. Land use in a buffer of 500m.was assessed and alfalfa insect abundance was estimated with sticky yellow traps.Numbers of catches of several herbivores and predators were related to the proportion of landscape components and several field variables. Results indicated that the proportion of orchards in the buffer negatively affected the abundance of predators on alfalfa; likely because orchards treated with pesticides are a sink for predators moving in the landscape, among other possible causes. Other landscape variables such as noncrop habitats, winter cereals, and landscape diversity analyzed by the Shannon index had a minor influence. Among field variables, field size influenced positively the abundance of insects on alfalfa whereas alfalfa growth stage and age affected positively or negatively the different herbivores and predators. Of course, abundance of predators and prey was affected by the abundance of prey and predators, respectively. These findings suggest that a high proportion of intensively managed crops (orchards) in the landscape interferes with the role of alfalfa as a reservoir of predatory insects for adjacent crops and that the responses to local and landscape structures are temporal and species-specific as previously concluded for maize. Consequently, landscape and field management strategies to improve pest control must consider both types of variables as well as their changing influence when we modify them. info:eu-repo/semantics/acceptedVersion

Our work reports on the establishment of the neotropical parasitoid Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) for the first time in Europe. This larval parasitoid has been recorded in samples collected in commercial tomato crops in Catalonia (North-eastern Spain) from 2016 to the present. Dolichogenidea gelechiidivoris is considered to be a new biocontrol agent among the resident parasitoid complex of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). info:eu-repo/semantics/acceptedVersion

To understand trophic interactions and the precise ecological role of each predatory species, it is important to know which arthropod and plant resources are used by generalist predators in agroecosystems. Molecular approaches, such as the use of high-throughput sequencing (HTS), play a key role in identifying these resources. This study develops a multiprimer metabarcoding approach for screening the most common trophic interactions of two predatory arthropods with contrasting morphologies, Rhagonycha fulva (Coleoptera: Cantharidae) and Anthocoris nemoralis (Hemiptera: Anthocoridae) collected from a peach crop. To reduce the time and cost of this metabarcoding approach, we first evaluated the effect of using two different predator-pools of different size (10 and 23 individuals of the same species). We also used our system to analyze the performance of one and two primer pairs in the same library. Our results show that the analysis of 23 individuals together with the use of two primer pairs in the same library optimize the HTS analysis. Using these best-performing conditions, we then analyzed the entire bodies of field-collected predators as well as the washing solutions used to clean the insect bodies. We were able to identify both gut content (i.e., diet) and external pollen load (i.e., on the insects’ bodies). This study also demonstrates the importance of washing predatory insects’ bodies prior to HTS analysis when the target species have a considerable size (>10 mm) and hairy structures. This metabarcoding approach has significant potential for the study of trophic links in agriculture, revealing expected and unexpected trophic relationships. info:eu-repo/semantics/acceptedVersion

Development of conservation biological control programs requires the identification of sources that contribute to predator colonization of crops. Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) is an efficient polyphagous predator used in biological control programs in vegetable crops in Europe. We have developed a marking method based on spraying with a solution of the brine shrimp Artemia spp. (Anostraca: Artemiidae) cysts, followed by a PCR detection of Artemia DNA to monitor M. pygmaeus dispersal from banker plants to tomato crops. Experiments conducted in climatic chambers show that the topical application of this marking solution on M. pygmaeus does not significantly reduce adult longevity and that it is detected up to 6 d after the application. When this Artemia solution was applied on Calendula officinalis L. banker plants harboring M. pygmaeus and maintained outdoors, Artemia DNA was still detected on 62% of the insects after 6 d. The conducted field applications in commercial greenhouses have confirmed the usefulness of this method to monitor M. pygmaeus dispersal from banker plants to a newly planted tomato crop. This method can be used to assess arthropod movement, being an interesting molecular approach for further improving future pest management strategies. info:eu-repo/semantics/acceptedVersion

Our study aimed to assess the contribution of natural parasitism due toNecremnus tutaeRibes & Bernardo (Hymenoptera: Eulophidae) to the biological control ofTuta absoluta(Meyrick) (Lepidopera:Gelechiidae) in commercial plots where an IPM program based on the use of predatory mirid bugs was implemented. During the samplings, the presence of another parasitoid was detected and, therefore, a second part of our study intended to identify this species and to evaluate the importance of its natural populations in the biological control of the pest. Leaflets withT. absolutagalleries were collected during 2017–2020 from commercial tomato plots in the horticultural production area of Catalonia (Northeast Spain), including greenhouses, open fields, and roof covered tunnels that lack side walls. In the laboratory,T. absolutalarvae were classified as ectoparasitized, alive, or dead. Reared parasitoids from ectoparasitized larvae were mostly morphologically identified asNecremnussp. with parasitism rates that peaked in summer months with values between 9 and 15%. Some of these ectoparasitized larvae also yielded another parasitoid identified asDolichogenidea gelechiidivorisMarsh (Hymenoptera: Braconidae) by both morphological and molecular-DNA barcoding methods. In 2020, parasitism rates due toD. gelechiidivoristhat increased with season up to 22%. Our work reports for the first time in Europe the presence of the neotropical speciesD. gelechiidivorisadding this biocontrol agent to the resident parasitoid complex ofT. absolutain Spain.

Conservation biological control involves manipulation of the environment to enhance the efectiveness of natural enemies in controlling crop pests. In this study, we combined historical data, sticky trap sampling of tomato greenhouses and beat sampling of adjacent vegetation to identify which greenhouse characteristics, habitat management practices and landscape features favour an early colonisation of tomato greenhouses by the key mirid predator Macrolophus pygmaeus and its establishment in NE Spain. Results show that landscape composition and the use of Calendula ofcinalis banker plants inside the greenhouse are key factors. In general, greater amounts of herbaceous semi-natural cover at the landscape scale promoted M. pygmaeus colonisation, while the use of C. ofcinalis banker plants encouraged M. pygmaeus colonisation independently of the landscape context. We identifed host plants adjacent to tomato greenhouses that sustain M. pygmaeus populations; however, they did not have a major efect on M. pygmaeus colonisation compared to larger landscape and banker plant efects. Early colonisation of greenhouses by this predator species also translated into lower accumulated incidence of pests at the end of the sampling period. This study demonstrates the importance of active habitat management practices in promoting the early arrival of M. pygmaeus in greenhouses with delayed spontaneous colonisation. This study was funded by EU-funded projects, EUCLID (Project Number: 633999-2) and EMPHASIS (Project Number: 634179-2), the project AGL2016-77373-C2-1-R (Spanish Ministry of Economy and Competitiveness) and the CERCA Programme of the Generalitat de Catalunya. AA was partly supported by a Ramón Areces fellowship while writing this manuscript.

Knowing which arthropod and plant resources are used by generalist predators in agroecosystems is important to understand trophic interactions and the precise ecological role of each predatory species. To achieve this objective, molecular approaches, such as the use of high-throughput sequencing (HTS) platforms are key. This study develops a multi-primer metabarcoding approach and explores its suitability for the screening of the most common trophic interactions of two predatory species of arthropod with contrasted morphology, Rhagonycha fulva (Coleoptera: Cantharidae) and Anthocoris nemoralis (Hemiptera: Anthocoridae) collected in an organic peach crop. To save time and cost in this metabarcoding approach, we first evaluated the effect of two different predator-pool sizes (10 and 23 individuals of the same species), as well as the performance of using one or two primer pairs in the same library. Our results show that the analysis of 23 individuals together with the use of two primer pairs in the same library optimizes the HTS analysis. With these best-performing conditions, we analyzed whole bodies of field-collected predators as well as the washing solutions used to clean the insect bodies. Results showed that we were able to identify both, gut content (i.e. diet) as well as external pollen load (i.e. on the insects’ body), respectively. This study also demonstrates the need of washing predatory insects prior to HTS analysis when the target species have a considerable size and hairy structures. This metabarcoding approach has a high potential for the study of trophic links in agriculture, revealing both expected and unexpected trophic relationships.

Implementation of landscape approaches to conservation biological control programs requires the confirmation of putative sources that contribute to predator colonization of crops. Several predator species are known to play an important role in biological control programs in orchards worldwide. This study optimizes a DNA mark-capture procedure based on a topical application of a solution of grinded brine shrimp cysts, Artemia spp. (Anostraca: Artemiidae), followed by a conventional PCR to monitor predator dispersal from an alfalfa field to a neighboring peach orchard. Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) is a well-known predator present in orchards as well as in arable crops, which was used in this study to optimize the marking procedure. Firstly, the acquisition and the retention time of the Artemia marking method were tested in greenhouse trials either directly by spraying them with the Artemia solution, or indirectly via residual contact on caged plants after the spray. The topical mark remained detectable on O. laevigatus after 6 days, and 50% of the tested predators were positive 3 days after walking on the sprayed plants. Secondly, after spraying the Artemia solution on a 25m2 strip of an alfalfa crop neighboring to a peach orchard, several common predator species were collected using sticky traps placed between both crops after the alfalfa cuts. After PCR analysis with the Artemia specific primers, 32% of the analyzed predators (coccinellids, anthocorids, chrysopids, and mirids) showed their movement from alfalfa to peach. This study confirms the usefulness of this marking method to monitor dispersal of biological control agents between neighboring crops. info:eu-repo/semantics/acceptedVersion

The β-aminobutyric acid (BABA) is a plant defense priming compound highly effective in controlling important tomato diseases and plant-parasitic nematodes. It has also been shown to induce resistance against phytophagous insects such as aphids. This study examines the effect of BABA on the performance of the tomato pest Bemisia tabaci (MEAM 1, previously known as Biotype B) and its zoophytophagous predator Macrolophus pygmaeus under laboratory and greenhouse conditions. Tomato plants were treated with BABA 25 mM applied by soil drenching. The effect of BABA on the fertility and juvenile development of two generations of B. tabaci and M. pygmaeus was evaluated. Our results showed no effect of BABA on the juvenile development or adult fecundity/fertility of both the whitefly and its predator. The non-interference of BABA with M. pygmaeus and B. tabaci assures that the control of the whitefly with this mirid bug will not be affected when this elicitor is applied to the crop. Further studies are needed to clarify the mechanisms underlying BABA-plant-whitefly-predatory myrids interactions. info:eu-repo/semantics/acceptedVersion

First we describe the different types of biocontrol used in greenhouses and present examples of each type. Next we summarize the history of greenhouse biocontrol, which started in 1926, showed a problematic period when synthetic chemical pesticides became available after 1945, and flourished again since the 1970s. After 1970, the number of natural enemies becoming available for commercial augmentative biocontrol in greenhouses grew very fast, as well as the industry producting these control agents. Biocontrol of the most important clusters of greenhouse pests is summarized, as well as the taxonomic groups of natural enemies that play a main role in greenhouses. More than 90% of natural enemy species used in greenhouses belong to the Arthropoda and less than 10%, many belonging to the Nematoda, are non-arthropods. This is followed by sections on finding and evaluation of potential biocontrol agents, and on mass production, storage, release and quality control of natural enemies. Since the 1970s, production of biocontrol agents has moved from a cottage industry to professional research and production facilities. Many efficient agents have been identified, quality control protocols, mass-production, shipment and release methods matured, and adequate guidance for farmers has been developed. Most natural enemy species (75%) are produced in low or medium numbers per week (hundreds to a hundred thousand), and are applied in situations where only low numbers are needed, such as private gardens, hospitals, banks, and shopping malls. The other 25% of the species are produced in numbers of 100,000 to up to millions per week and regularly released in many of the greenhouse crops. Microbial pesticides are predominantly used as corrective treatments in greenhouse crops where natural enemies are providing insufficient control. Europe is still the largest commercial market for arthropod greenhouse biocontrol agents, and North America is the largest market for microbial control agents. We then continue with a discussion on the pros and cons of use of polyphagous predators, and the use of semiochemicals. Finally, we summarize factors that indicate a positive future for greenhouse biocontrol, as well as developments frustrating its implementation.

Zoophytophagous mirid species, that feed and develop either on prey or plant resources, are often found simultaneously on the same host. Hence, these species can engage in both intraguild predation and cannibalism, which can pose a threat to mirid eggs. Ovipositing females may respond to such risks of predation on their eggs by reducing the number of eggs laid or selecting safer oviposition sites. We tested the oviposition behaviour of Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae) females under the risk of cannibalism by M. pygmaeus males and intraguild predation by Nesidiocoris tenuis (Reuter) males (Hemiptera: Miridae) under laboratory conditions. Intraguild predators and cannibals were introduced during or after the oviposition period. The number of eggs laid (using counts of newly hatched nymphs) and their proportion on each part of a tomato plant were both measured. The results reveal that only cannibalism by M. pygmaeus males after the period of oviposition significantly decreased the number of hatched eggs. Cannibalism thus represents a greater risk to mirid eggs than intraguild predation. The M. pygmaeus female responded to the presence of potential intraguild predators (or competitors) by decreasing the number of eggs laid in the upper leaves. The results suggest that M. pygmaeus females avoid competition by N. tenuis, by laying fewer eggs on upper leaves. Cannibalism could regulate zoophytophagous predator populations under prey scarcity conditions and minimize the risk of crop damage associated with those biological control agents. info:eu-repo/semantics/acceptedVersion

The feeding habits of the generalist arthropod predators in agroecosystems are often difficult to determine, as they are small, mobile and live among the vegetation or in the soil. DNA-based gut-content analysis is a powerful tool that enables the study of arthropod predator–prey interactions. Predation on two of the main pests of Mediterranean lettuce crops, the lettuce aphid, Nasonovia ribisnigri, and the western flower thrips, Frankliniella occidentalis, as well as on Collembola, the most abundant non-pest prey, was studied. Generalist arthropods, like hoverflies, anthocorids (Orius spp.), coccinellids and spiders were collected in lettuce plots in two seasons (spring and summer) and analysed by conventional PCR using N. ribisnigri, F. occidentalis and Collembola-specific primers. Our results showed that in spring the main pest was N. ribisnigri, which was consumed by hoverfly larvae and coccinellids. In summer, the main pest was F. occidentalis, which was mainly predated by Orius spp. followed by hoverfly larvae. Spiders, which fed mainly on Collembola, did not seem to contribute to control of either target pest. This study offers a deeper knowledge of the trophic relationships present in Mediterranean lettuce crops, laying the groundwork for implementing biological control programmes based on the conservation of natural enemies.

MedISys is a media monitoring system initially intended for news items related to human health. The tool has how been extended by the Joint Research Centre, Universitat de Lleida and IRTA to also deal with plant health threats. This EFSA-funded project was based on a knowledge representation approach that generated an ontology, a formal representation of knowledge related to plant health threats. The ontology models plant pests and diseases, together with other concepts related with them: affected crops, hosts, vectors and symptoms. First of all, a collection of news sources related to plant health threats was collected to be monitored by MedISys. These sources included already known manually curated Web pages but also additional ones discovered by performing global Web searches using terms appearing in the ontology. Then, the news items coming from these sources were filtered using MedISys using a set of categories with keywords to identify those actually about plant health threats. Most of these categories focused on known threats and used terms associated with the 117 pests and diseases selected at the beginning of the project. Additionally, categories for unknown threats were also developed. In this case the categories included keywords that are usually used by experts to describe unknown threats and keywords related with symptoms expressions. All these MedISys categories combined provide mechanism to monitor plant health threats mentions in media, from newspapers to social media, ranging from those that explicitly mention a named threat (useful to monitor re-emerging threats or their spread) to those related to unknown ones (to monitor potential new threats). The project concluded with an evaluation of the e-mail alerts and reports generated by MedISys based on the previous categories. A survey and tests with real users were conducted and the results analysed to generate a set of recommendations and improvements to facilitate the use of MedISys as a plant health threats monitoring tool.

BACKGROUND The aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) and the thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) are common pests in Mediterranean lettuce crops, where Orius spp. are common generalist predators. Predation by Orius spp. was studied in a lettuce plot by conventional polymerase chain reaction (PCR) and real-time PCR analyses using specific primers of both main pests. Also, high-throughput sequencing was used to have a wider approach of the diet of these predators in natural field conditions. RESULTS Molecular analyses indicated a higher predation on N. ribisnigri in spring and on F. occidentalis in summer. Predation on alternative prey, like Collembola, was also found in both seasons. Real-time PCR was more sensitive than conventional PCR in showing the target trophic links, whereas high-throughput sequencing revealed predation on other natural enemies – intraguild predation (IGP), showing other trophic interactions of Orius majusculus within the studied ecosystem. CONCLUSIONS This study gives important information about the trophic relationships present in Mediterranean lettuce crops in different periods of the year. The detected predation by Orius spp. on alternative prey, as well as on other natural enemies, should be further investigated to clarify whether it adds or detracts to the biological control of N. ribisnigri and F. occidentalis. © 2015 Society of Chemical Industry

Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) (western flower thrips, WFT) is a key pest in a range of crops worldwide. Anthocorid species (Hemiptera) are important natural enemies of thrips. Several experiments were undertaken to determine whether a thrips lure, methyl isonicotinate (MI), affected the behaviour of WFT and anthocorids found in outdoor crops. Currently, this volatile compound is used in conjunction with sticky traps for monitoring thrips predominantly in greenhouses in Northern Europe. In the present study, in a nectarine [Prunus persica (L.) (Rosaceae)] orchard and an outdoor capsicum [Capsicum annuum L. (Solanaceae)] crop in Spain, blue sticky and white water traps with MI caught significantly more WFT than traps without MI. The volatile compound also significantly increased both blue sticky and white water trap capture of anthocorids – predominantly Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) – in the capsicum crop. These results indicate that the behaviour of both WFT and O. laevigatus were altered by the presence of the compound and suggest there is potential to develop novel tools based on MI in conjunction with biological control strategies for thrips management.

Within the genus Macrolophus (Heteroptera: Miridae), the species M. costalis (Fieber), M. melanotoma (Costa) and M. pygmaeus (Rambur) are present in the Mediterranean region on a wide variety of plant species. While M. costalis can easily be separated from the other two by the black tip at the scutellum, M. pygmaeus and M. melanotoma are cryptic species, extremely similar to one another in external traits, which have resulted in misidentifications. M. pygmaeus is an efficient biological control agent, both in greenhouse and field crops. The misidentification of these cryptic species could limit the effectiveness of biological control programs. Although morphology of the left paramere of the male genitalia has been used as a character for identification of these two cryptic species, there is controversy on the reliability of this character as a taxonomic tool for these species. Using geometric morphometric techniques, which are a powerful approach in detecting slight shape variations, the left parameres from these three Macrolophus species were compared. The paramere of M. costalis was larger and had a different shape than that of M. melanotoma and M. pygmaeus; however, no differences in size or shape were found between the left paramere of M. melanotoma and that of M. pygmaeus. Therefore, our results confirm that this character is too similar and it cannot be used to discriminate between these two cryptic species.

BACKGROUND Hoverflies (Diptera: Syrphidae) are generalist predators of a great variety of pests. Nasonovia ribisnigri (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g. Collembola). A semi-field experiment was conducted in an experimental lettuce plot where hoverfly predation on N. ribisnigri, F. occidentalis and Collembola was studied by conventional PCR and qPCR using specific primers, as well as by next-generation sequencing (NGS) in order to reveal other potential trophic interactions. RESULTS Trophic linkages between hoverflies and N. ribisnigri were the strongest both in spring and summer. F. occidentalis and Collembolans were also detected in both seasons, but with less frequency. qPCR detected a higher frequency of consumption than conventional PCR when both tests were run at optimal conditions. NGS analyses showed intraguild predation on other hoverfly species, as well as on anthocorids, spiders and even aphid parasitoids. CONCLUSIONS Conventional PCR and qPCR provided important insights into Mediterranean hoverfly species predation on target pest and non-pest prey. NGS gave a complementary approach revealing a broader diet of these predators within the studied ecosystem. © 2014 Society of Chemical Industry

Modified atmospheres (MAs) are safe and environmentally friendly alternatives to control pests in stored products. However, to accommodate the requirements of the food industry, the control of insects by a MA can be a too lengthy process. This paper describes the potential of sulphur dioxide as an additive to reduce the long lethal exposure of modified atmospheres (MA) enriched with carbon dioxide for major stored product pests. Specifically, we evaluated whether the addition of SO2 (0–30,000 ppm) to a high-CO2 content of 70%–95% MA could enhance its insecticidal effect for the control of Sitophilus oryzae and Tribolium confusum. The addition of 15,000 ppm and 30,000 ppm of SO2 to 95% CO2 enhanced control up to 100% in comparison to CO2 alone for S. oryzae and T. confusum adults when treated for one day in all of the substrates tested. However, the effectiveness of adding SO2 at reduced contents was lower and depended on the substrate and pest species considered. The addition of SO2 also increased the mortality of all of the developmental stages of S. oryzae. The increase in mortality with the addition of SO2 was also observed when included with 70% CO2. Therefore, the addition of SO2 can be considered a feasible means of shortening the length of treatment necessary to achieve the control of these two pests using a high-CO2 MA.

Biological pest control in greenhouse crops is usually based on periodical releases of mass-produced natural enemies, and this method has been successfully applied for decades. However, in some cases there are shortcomings in pest control efficacy, which often can be attributed to the poor establishment of natural enemies. Their establishment and population numbers can be enhanced by providing additional resources, such as alternative food, prey, hosts, oviposition sites or shelters. Furthermore, natural enemy efficacy can be enhanced by using volatiles, adapting the greenhouse climate, avoiding pesticide side-effects and minimizing disrupting food web complexities. The special case of high value crops in a protected greenhouse environment offers tremendous opportunities to design and manage the system in ways that increase crop resilience to pest infestations. While we have outlined opportunities and tools to develop such systems, this review also identifies knowledge gaps, where additional research is needed to optimize these tools.

The larvae of many hoverflies (Diptera: Syrphidae) are important polyphagous predators used in integrated pest management programs. Because the accurate identification of preimaginal stages by morphological characters is difficult, we have developed a multiplex PCR to identify the immature and/or adult stages of the most common syrphid species in Mediterranean vegetable crops: Episyrphus balteatus, Scaeva pyrastri, Eupeodes corollae, Meliscaeva auricollis, Sphaerophoria scripta, and Sphaerophoria rueppellii. The latter two species were amplified by the same primer pair due to the high similarity of their cytochrome oxidase subunit I sequences. Additionally, the assay included a primer pair targeting Diplazon laetatorius, a common koinobiont ichneumonid endoparasitoid of predatory syrphid larvae. The multiplex PCR assay proved to be highly specific and sensitive, and it was used to study the assemblage of hoverfly species in larval stage in two Mediterranean lettuce crops in two consecutive years. The molecular analysis revealed that Eu. corollae, Ep. balteatus, and Sph. scripta/Sph. rueppellii were the species present in the investigated fields. Species composition differed depending on sampling date and whether the larvae were collected on the plants or on the ground. The parasitoid D. laetatorius was not detected in any of the analyzed hoverfly larvae, suggesting low-parasitism pressure in the studied syrphid populations. The wide distribution of most of these syrphid species makes this multiplex PCR assay an ideal tool to deepen our knowledge on the ecology of these polyphagous hoverfly species in preimaginal stages and to improve the use of hoverflies to control insect pests. This study has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) (Projects AGL2008-00546 and AGL2011-24349). P. Gomez-Polo was supported by a FPI Grant funded by the MINECO.

MedISys is a media monitoring system initially intended for news items related to human health. The tool has how been extended by the Joint Research Centre, Universitat de Lleida and IRTA to also deal with plant health threats. This EFSA-funded project was based on a knowledge representation approach that generated an ontology, a formal representation of knowledge related to plant health threats. The ontology models plant pests and diseases, together with other concepts related with them: affected crops, hosts, vectors and symptoms. First of all, a collection of news sources related to plant health threats was collected to be monitored by MedISys. These sources included already known manually curated Web pages but also additional ones discovered by performing global Web searches using terms appearing in the ontology. Then, the news items coming from these sources were filtered using MedISys using a set of categories with keywords to identify those actually about plant health threats. Most of these categories focused on known threats and used terms associated with the 117 pests and diseases selected at the beginning of the project. Additionally, categories for unknown threats were also developed. In this case the categories included keywords that are usually used by experts to describe unknown threats and keywords related with symptoms expressions. All these MedISys categories combined provide mechanism to monitor plant health threats mentions in media, from newspapers to social media, ranging from those that explicitly mention a named threat (useful to monitor re-emerging threats or their spread) to those related to unknown ones (to monitor potential new threats). The project concluded with an evaluation of the e-mail alerts and reports generated by MedISys based on the previous categories. A survey and tests with real users were conducted and the results analysed to generate a set of recommendations and improvements to facilitate the use of MedISys as a plant health threats monitoring tool.

Habitat manipulation and increasing biodiversity are important approaches that enhance biological control of pests, but it is important to evaluate the relative benefits of specific plant species when designing conservation programs. Orius insidiosus Say (Hemiptera: Anthocoridae) is an important predator of thrips and aphids that also feeds on plants. It is the target of conservation biological control programs. Despite O. insidiosus' relevance, little is known about the effects of plant subsidies on predator performance or nutritional status. Here, we examined the influence of restricting the pollen and nectar resources of five plant species (alyssum, buckwheat, phacelia, fava bean, and chamomile), and how increasing plant diversity affects O. insidiosus fecundity, survival, and nutritional status. Plant species varied in their suitability for O. insidiosus, which was driven in part by the availability of the pollen or nectar resources. Offering plants as a mixture did not improve fecundity; however, the plant least preferred for oviposition under no-choice tests (fava bean) became the preferred egg-laying site when the plants were offered in combination. We conclude that the benefits obtained by O. insidiosus vary among plant species, and that increasing plant diversity can have unpredicted, positive effects on insect fitness.

In conservation biological control programs, provision of the required resources (shelter, food, oviposition sites) can be achieved by means of the use of insectary plants. This is especially important in the case of omnivorous predators that feed on prey and plant materials, and where the availability of plant resources plays a significant role in their conservation. An important predator of thrips and other pests in the Mediterranean is the omnivorous bug Orius majusculus (Reuter) (Hemiptera: Anthocoridae). The objective of this study was to evaluate the fertility, fecundity and longevity of O. majusculus on alyssum, (Lobularia maritima L.) with and without prey (Ephestia kuehniella eggs), and compare it with green bean pods. Additionally, the effects of the breeding colony of the individuals on the fertility of O. majusculus were studied. Fecundity on both plants without prey was low; however the addition of prey significantly increased the number of eggs laid, especially on alyssum. The longevity differed significantly among diets, being longer for alyssum with prey eggs. Survival on alyssum without prey was not statistically different from green bean with prey, which shows the potential of alyssum to conserve O. majusculus during times of prey scarcity. The fertility of O. majusculus females was significantly higher on the diets of both plant materials when prey was included. Our results showed that alyssum can provide resource subsidies for O. majusculus during times of prey scarcity in the field.

Most predators and parasitoids feed on plant-provided food (nectar, pollen) or engage in herbivory during at least part of their life stages. Plant feeding by these insects plays an important role in driving predator-herbivore dynamics. Thus, understanding the effects of plant feeding on omnivores could be an important element in improving biological control strategies. The mirid Macrolophus pygmaeus is an omnivorous heteropteran predator of whitefly and other pests. Unlike other predators that need to seek out accessible nectar to meet their carbohydrate requirements, mirid bugs can access the plant's carbohydrate resources by feeding directly on plant tissues. Leaf and stem feeding could be seen as a nutritional surrogate that allows mirids to become independent of nectar availability. However, to date feeding experiments have not yet considered nectar feeding by these mirid predators. In this study we demonstrate that M. pygmaeus survival is prolonged on broad bean plants featuring extrafloral nectar as compared to broad bean with extrafloral nectaries removed, irrespective of the presence of cattail pollen. Survival on extrafloral nectar was comparable to the survival by individuals kept on broad bean provided with eggs of Ephestia kuehniella as prey. Also, a greater proportion of mirid females laid eggs when extrafloral nectar was available as compared to those confined on nectariless plants without supplemental food.

The relationship between the oviposition site preferences of predators in the face of intraguild competitors has received little attention, but it likely shapes the reproductive ecology of predatory species. In this study, oviposition intensity and the within-plant distribution of Orius insidiosus (Heteroptera: Anthocoridae) and Nabis americoferus (Heteroptera: Nabidae) eggs on Phaseolus vulgaris plants was studied when the two species were present independently or in combination. Both predators laid more eggs in the presence of the other species relative to when they were only exposed to conspecifics. When only exposed to conspecifics, O. insidiosus preferred to lay eggs on leaves and petioles on the upper half of the plant, whereas N. americoferus laid eggs mostly on the petioles and petiolules equally throughout the height of the plant. But when both species were present, O. insidiosus preferred to lay eggs on the leaf, whereas N. americoferus altered their behavior to lay an even greater prop...

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.

The development of alternative treatments for pest control in food commodities is an increasing demand from the food industry, which should meet consumer demands for the reduced use or elimination of pesticides. The use of carbon dioxide (CO2) at high pressure is one of the most rapid options for arthropod pest control among current commercial treatments, offering complete control within hours. The present study aimed to establish the efficacy of the technique against different stages of several insect and mite pests that affect stored-food products. Standard food diets containing eggs, larvae, pupae and adults of Oryzaephilus surinamensis, Cryptolestes ferrugineus, Lasioderma serricorne, Sitophilus oryzae, Rhyzopertha dominica, Acanthoscelides obtectus, Ephestia kuehniella, Liposcelis bostrychophila and Tyrophagus putrescentiae were treated with CO2 for different times at two high pressures, 15 and 20 bar. A high level of control was achieved for most species and development stages when they were treated with CO2 at 20 bar for 60 min. However, the efficacy at 15 bar was much lower. The eggs of L. bostrychophila and L. serricorne showed the highest tolerance of all species/stages and survived the most extreme conditions tested. The beetle O. surinamensis, the moth E. kuehniella, and the mite T. putrescentiae were easier to kill than the other species tested. Our results confirmed that the use of high-pressure CO2 offers an effective and fast way to control most stored-product pests that affect food commodities.

Intraguild predation (IGP) among predatory species can influence many plant-arthropod associations. However, the relevance of IGP is poorly understood for truly omnivorous species such as those that can complete development on both animal and plant diets. Here we test the hypothesis that IGP among two omnivorous mirids is more common when extraguild food is either absent or not suitable. Laboratory experiments were performed in experimental cages in order to determine the effect of intraguild prey densities and diet availability on direction and intensity of IGP between Dicyphus tamaninii and Macrolophus caliginosus (Heteroptera: Miridae). Intraguild predation was symmetrical between the two mirid species in the absence of alternative food. Increasing densities of intraguild prey enhanced drastically the incidence of IGP. Intraguild predation was reduced when mirids were in the presence of green or red tomato fruits, but the presence of any other extraguild resources had no impact on IGP level. H...

Modified atmospheres based on high carbon dioxide (CO 2 ) content offer an alternative to fumigation for arthropod pest control in durable commodities. The present study aimed to establish the efficacy of using modified atmospheres during packaging (MAP) to control a wide spectrum of pests and their respective developmental stages that affect final food products during storage and commercialization. Two high (50% and 90%) CO 2 MAPs were applied to identify the pest species and developmental stages that were most tolerant to treatments. Standard food diets containing eggs, larvae, pupae and adults of Lasioderma serricorne , Cryptolestes ferrugineus , Oryzaephilus surinamensis , Tribolium confusum , Rhyzopertha dominica , Sitophilus oryzae , Ephestia kuehniella , Plodia interpunctella , Liposcelis bostrychophila and Tyrophagus putrescentiae were confined in sealed plastic bags filled with the two MAPs. The pest species and developmental stages showed different sensitivity to the two MAP treatments. The beetles S. oryzae , R. dominica , C. ferrugineus and L. serricorne were among the most tolerant species as pupae or eggs. The mite T. putrescentiae was also highly tolerant. Moths were easier to kill than the other species tested. Our results confirmed that MAP could be applied to final food products during packaging to control the residual occurrence of pests after the manufacturing process and to prevent further infestation in the final packages reaching consumers.

The development time for eggs and nymphs and female fertility were determined for Nesidiocoris tenuis Reuter (Het., Miridae: Dicyphini) at 15, 20, 25, 30, 35 and 40 ± 1°C, using tomato, Solanum esculentum (Miller), as substrate and eggs of Ephestia kuehniella Zeller as substitute prey. At 40°C, N. tenuis was unable to develop and barely reproduced. Egg development ranged from 30.8 days at 15°C to 6.3 days at 35°C. The cumulative thermal requirements for the eggs were 148.6 degree days (°d) and the lower thermal threshold, 10.3°C. The duration of the nymphal instar decreased from 55.9 days at 15°C to 8.6 days at 35°C. The thermal constant for the nymphs was 182.3 °d and the lower thermal threshold 11.7°C. No nymphs survived at 40°C, and the highest mortalities were at extreme temperatures (15 and 35°C). Female and male weights were influenced significantly by temperature. The fertility of N. tenuis females was reduced greatly at 15 and 40°C. The highest fertility during an observation period of 18 days following female emergence (79.5–60.0 nymphs per female) was within the temperature range of 20 to 35°C. Fertility was related directly to female weight and temperature (r2 = 0.932). Based on development, reproduction data and thermal requirements, the optimum temperature range for N. tenuis was established as being between 20 and 30°C. Overall, N. tenuis is the most thermophilous of all dicyphines from vegetable crops in the Mediterranean area studied so far.

Macrolophus caliginosus is a polyphagous mirid bug native to the Mediterranean area where it is widely used as a biological control agent, both in protected and open-field vegetable crops. Its reproductive biology remains largely unknown and a better understanding of it will improve mass rearing and release strategies. In the present work, we studied the development of reproductive organs in females and males and how age conditioned receptiveness to mating in both sexes. Females with mature eggs in their ovarioles appear 3–4 days after adult molt with a similar pattern of ovary maturation in virgin females as in females that were kept with males of the same age. Newly molted males were found to already have active sperm in their seminal vesicles but their accessory glands did not completely develop until 3 days later. Receptivity for copulation paralleled ovarian and accessory gland maturation.

Macrolophus pygmaeus (Rambur, 1839) (Insecta, Heteroptera, Miridae) is a predator of key vegetable crop pests applied as a biocontrol agent in the Mediterranean region. M. pygmaeus and M. melanotoma (A. Costa, 1853) are cryptic species with great morphological similarity which results in their misidentification and negative consequences for the conservation of their populations on greenhouse and outdoor crops. In order to find out specific markers for their separation we studied the karyotype, male meiosis and heterochromatin composition of these species and additionally of a third species (as a reference one), M. costalis Fieber, 1858. We demonstrate here that all the three species share achiasmate male meiosis and sex chromosome pre-reduction. On the other hand, the species differ in karyotype, with 2n=28 (26+XY) in M. pygmaeus, 2n=27 (24+X1X2Y) in M. costalis, and 2n=34 (32+XY) in M. melanotoma, and heterochromatin distribution and composition. In addition, the species differ in sperm morphology: sperm cells of M. costalis are significantly longer with longer head and tail than those of M. melanotoma and M. pygmaeus, whereas sperm cells of M. melanotoma have a longer tail than those of M. pygmaeus. All these characters can be used as markers to identify the species, in particular the cryptic species M. melanotoma and M. pygmaeus. This study has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) (Project AGL2011-24349), and by a travel grant from the University of Lleida - Fundació “La Caixa” to Dr Grozeva. The chromosome analysis was performed using microscope Axio Scope A1 – Carl Zeiss Microscopy upgraded by the project WETLANET (FP7 CSA – SUPPORT ACTION, GA 229802). We thank cordially Prof. Dr V. Kuznetsova for the valuable advices to improve the manuscript

The mirid bugs Macrolophus pygmaeus and M. costalis use substrate-borne vibrational signals during pair formation and in male-male interactions as determined by laser vibrometry. The vibrational communication of Macrolophus is more complex than in other mirids, with a signal repertoire composed of two elements, only produced by males, while the females are mute. The 'yelp' signal consists of one or several consecutive brief pulses with harmonic structure and is commonly produced by stationary males before mating, as a key-element of courtship. 'Yelping' is also associated with contacts between males. The 'roar' signal differs from 'yelps' in that it has a broadband frequency pattern, a longer and more variable duration than 'yelping', and is produced by males in association with walking on the leaf. Playback experiments did not affect male vibration emission, but when 'roaring' was used as stimulus, it elicited a significant increase in the time spent walking. We detected significant differences between M. costalis and M. pygmaeus in some spectral parameters of the 'roar' and 'yelp' signals, so these signals could contain species-specific information. We conclude that 'roaring' and 'yelping' vibrational signals are used by Macrolophus in social communication, in particular in the context of mating behavior. CG was funded by an Erasmus Training Grant. OA was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) (Project AGL2011-24349)

The mirid Macrolophus caliginosus Wagner (Hemiptera: Miridae), and the syrphids, Sphaerophoria rueppellii (Wiedemann), Sphaerophoria scripta (L.), and Episyrphus balteatus (DeGeer) (Diptera: Syrphidae), belong to the aphidophagous guild, feeding on aphids (Hemiptera: Aphididae) in Mediterranean vegetable crops. The direction, symmetry, and intensity of intraguild predation between different instar combinations of syrphids and mirid were studied in an arena without plants. Moreover, predatory interactions between syrphids and mirids on plants were also evaluated. The results obtained in the arena without plants demonstrated mutual intraguild predation, i.e., syrphid eggs were highly susceptible to predation, whereas mirid nymphs and adults were attacked by syrphid larvae. All syrphid species showed the same propensity to predation, which was unaffected by parasitism of syrphid larvae by Diplazon laetatorius (Fabricius) (Hymenoptera: Ichneumonidae). Sphaerophoria scripta eggs were less susceptible to predation than those of the two other syrphid species. The experiment performed on plants showed different results. Predation by syrphid larvae on mirids never exceeded 10%, while 100% of syrphid eggs were preyed upon after 48 h. Intraguild predation rates were not influenced by the presence or absence of aphids on the plants. This study demonstrated that results obtained from studying intraguild predation in arenas that are highly artificial should be interpreted cautiously. Depending on the colonization history of a particular habitat in the field, syrphids should be more vulnerable to predation by mirids than vice versa.

This work presents the results of an investigation that aimed to evaluate the effectiveness of releases of the omnivorous predator Macrolophus caliginosus Wagner (Heteroptera, Miridae) in the control of Bemisia tabaci Gennadius (Homoptera, Aleyrodidae) on greenhouse melon. Two greenhouse trials were performed, one in spring and one in summer. Adults of M. caliginosus were released at two release rates (two and six per plant) in an initial infestation of 10 adult whitefly per plant. The high release rate did control the whitefly populations. Results of the lower release ratio did not work in the second trial, presumably due to excessive pruning of the crop that may have affected predator establishment. No damaged fruits were recorded. Laboratory trials were also done to examine the effects of plant and variable prey availability on predator fertility and survivorship. Results showed that low-prey availability significantly reduced survivorship and fertility of M. caliginosus , and explained why predator establishment was the same for both predator release rates.

Colonization of tomato greenhouses by native predatory mirid bugs at the end of the spring cycle is common in the western Mediterranean area when no broad-spectrum insecticides are applied. Due to their polyphagy, these predators interact with pest populations and also with other natural enemies present in the crop. In this work we evaluate the abundance and timing of greenhouse colonization by these predators and their interaction with the greenhouse whitefly Trialeurodes vaporariorum, a key crop pest, and its introduced parasitoid Encarsia formosa. Although quite unpredictable, natural colonization of greenhouses by Macrolophus caliginosus and Dicyphus tamaninii, the two predominant species in our location, usually leads to the establishment of predator populations in the crop that subsequently prey on greenhouse whitefly. No preference for parasitized pupae was observed in greenhouse samples, while laboratory experiments revealed a marked tendency to avoid parasitoid pupae. In our area, IPM programs for greenhouse tomatoes and other vegetables should take advantage of the presence of this predator complex by allowing the immigration and establishment of its populations without disturbing them with highly toxic and non-selective insecticides.

Some Mediterranean greenhouses are inserted in a landscape of open fields, non-agricultural and woody habitats. Both the greenhouse whitefly and its polyphagous predators are well adapted to protected and field crops. The phenology and intensity of whitefly and predator exchange between greenhouses and surrounding habitats were investigated in two different zones of northern Spain. Whiteflies colonised greenhouses earlier and built up high populations before predators established in the crop. Both the abundance of vegetation and the topographic characteristics of the environment surrounding greenhouses affected the numbers of predators entering the tomato crop through the greenhouse openings whereas whitefly migration was only affected by the topography around the greenhouses. These results are discussed in terms of biological control of greenhouse pests by naturally occurring predators.

In northeast Spain, the most common predators found in tomato Þelds and greenhouses are the mirids Macrolophus caliginosus Wagner and Dicyphus tamaninii Wagner. Natural colonization occurs during the growing season and both species prey on whitesies. Because D. tamaninii can damage tomato fruits during periods of prey scarcity, a semiÞeld experiment was carried out to evaluate whether the presence of M. caliginosus affects damage produced by D. tamaninii. In a tomato greenhouse, 60plants were individually caged and distinct predator treatments were introduced: D. tamaninii, D. tamaninii eggs of Ephestia kuehniella Zeller, D. tamaninii M. caliginosus, M. caliginosus alone, and a control without any insect. Damage to tomato fruits was recorded (25% of the fruit) in all the treatments with D. tamaninii, whereas no signiÞcant damage was detected with M. caliginosus alone. Finally, no intraguild predation was detected between both mirid species.

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.

Dicyphus tamaninii and Macrolophus caliginosus are predatory bugs that significantly contribute to control of pests in tomato crops following early colonisation in spring from winter refuges. This paper aimed to determine the influence of the richness of nearby potential predator sources at the time of arrival, amount and establishment of the mirid bugs in tomato fields. For this, six tomato fields were selected that showed a gradient of vegetational settings in the landscape. Crops and non-crop vegetation were sampled with a vacuum suction sampler and abundance of potential colonising predators was estimated. Soon after transplantation of tomatoes, weekly visual counts on the crop were initiated and continued for 8 weeks to estimate densities of Trialeurodes vaporariorum adults, the most abundant pest, and predator adults and nymphs. Time of predator arrival in each field, which varied between 6 and 8 weeks after seedling transplantation, was not related to the respective predator abundance in the surrounding vegetation. Eleven weeks after transplantation, fields differed in their cumulative numbers of insect-days (greenhouse whitefly, predator adults and nymphs). Differences in predator-days were not related to densities of greenhouse whitefly-days but to predator abundance in field surroundings. Fields were also colonised by predators coming from distant sources. Mirid bugs were more abundant in outer rows, particularly in fields with close predator sources and were concentrated on plants with higher whitefly densities. Predator nymphs were detected soon after adult arrival and distributed in the field mostly according to adult predator or prey spatial pattern. Presence of winter refuges for predators in nearby habitats increases the amount of colonisation. However, in order to rely on predator colonisation into fields, the stimuli involved in the predator movement from winter refuges to crops and the predator dispersal capacity should be further investigated.

Within the genus Macrolophus (Heteroptera: Miridae), the species M. costalis (Fieber), M. melanotoma (Costa) and M. pygmaeus (Rambur) are present in the Mediterranean region on a wide variety of plant species. While M. costalis can easily be separated from the other two by the black tip at the scutellum, M. pygmaeus and M. melanotoma are cryptic species, extremely similar to one another in external traits, which has resulted in misidentifications. M. pygmaeus is an efficient biological control agent, both in greenhouse and field crops. The misidentification of these cryptic species could limit the effectiveness of biological control programs. Although the morphology of the left paramere of the male genitalia has been used as a character for identification of these two cryptic species, there is controversy surrounding the reliability of this character as a taxonomic tool for these species. Using geometric morphometric techniques, which are a powerful approach in detecting slight shape variations, the left parameres from these three Macrolophus species were compared. The paramere of M. costalis was larger and had a different shape to that of M. melanotoma and M. pygmaeus; however, no differences in size or shape were found between the left paramere of M. melanotoma and that of M. pygmaeus. Therefore, our results confirm that this character is too similar and it cannot be used to discriminate between these two cryptic species. This study has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) (Project AGL2011-24349 and AGL2014-53970-C2-2-R).

The aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) and the thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) are common pests in Mediterranean lettuce crops, where Orius spp. are common generalist predators. Predation by Orius spp. was studied in a lettuce plot by conventional polymerase chain reaction (PCR) and real-time PCR analyses using specific primers of both main pests. Also, high-throughput sequencing was used to have a wider approach of the diet of these predators in natural field conditions.Molecular analyses indicated a higher predation on N. ribisnigri in spring and on F. occidentalis in summer. Predation on alternative prey, like Collembola, was also found in both seasons. Real-time PCR was more sensitive than conventional PCR in showing the target trophic links, whereas high-throughput sequencing revealed predation on other natural enemies - intraguild predation (IGP), showing other trophic interactions of Orius majusculus within the studied ecosystem.This study gives important information about the trophic relationships present in Mediterranean lettuce crops in different periods of the year. The detected predation by Orius spp. on alternative prey, as well as on other natural enemies, should be further investigated to clarify whether it adds or detracts to the biological control of N. ribisnigri and F. occidentalis.

Hoverflies (Diptera: Syrphidae) are generalist predators of a great variety of pests. Nasonovia ribisnigri (Hemiptera: Aphididae) and Frankliniella occidentalis (Thysanoptera: Thripidae) are two common pests in Mediterranean lettuce crops, where they occur alongside alternative prey (e.g., Collembola). A semi-field experiment was conducted in an experimental lettuce plot where hoverfly predation on N. ribisnigri, F. occidentalis and Collembola was studied by conventional PCR and qPCR using specific primers, as well as by next-generation sequencing (NGS) in order to reveal other potential trophic interactions.Trophic linkages between hoverflies and N. ribisnigri were the strongest both in spring and summer. F. occidentalis and Collembolans were also detected in both seasons, but with less frequency. qPCR detected a higher frequency of consumption than conventional PCR when both tests were run at optimal conditions. NGS analyses showed intraguild predation on other hoverfly species, as well as on anthocorids, spiders and even aphid parasitoids.Conventional PCR and qPCR provided important insights into Mediterranean hoverfly species predation on target pest and non-pest prey. NGS gave a complementary approach revealing a broader diet of these predators within the studied ecosystem.

Bemisia tabaci is an extremely polyphagous pest that causes direct damage and can act as a vector of viral plant diseases. The activity of natural enemies can be exploited by employing proper conservation and augmentation techniques. In addition to use of extant fauna, importation of parasitoids belonging to the genera Encarsia and/or Eretmocerus and of various predators has been successfully employed in greenhouses and out of doors. Biological control practice in greenhouses differs greatly in warmer climates, where interchanges of the pest and its enemies with the outdoor environment are possible, than in cold countries where the crop is more isolated. Recent successes in the biological control of Trialeurodes vaporariorum and B. tabaci in greenhouses and out of doors lead the way to a better understanding of the types of studies necessary for implementing future programs. Although certain natural enemy species have proven effective components in B. tabaci control, there are still unexplored, potentially valuable species in many areas of the world. This paper reviews the identity and biological attributes of known natural enemies, summarizes the studies conducted on them during the last decade, reviews current efforts in biological control of B. tabaci in greenhouse and field crops, and highlights research gaps and directions deserving further development.

Predation rate and nymphal development time were determined for four predatory bugs (Dicyphus tamaninii Wagner andMacrolophus caliginosus Wagner [Het.:Miridae],Orius laevigatus (Fieber) andO. majusculus (Reuter) [Het.:Anthocoridae], on cucumber withAphis gossypii Glover (Hom.:APhididae) as prey and for both mirids also on tomato withMacrosiphum euphorbiae (Thomas) as prey. All four predator species were able to achieve adulthood feeding on both aphids. The developmental period ofD. tamaninii nymphs was the longest and the shortest was forO. majusculus. During nymphal developmentD. tamaninii consumed greater numbers of both aphids thanM. caliginosus, whileOrius’ consumption ofA. gossypii was intermediate. Average daily predation was higher forD. tamaninii than forM. caliginosus, but was not different from bothOrius species. FemaleD. tamaninii exhibited a typical type-II functional response when preying on varying densities ofA. gossypii nymphs.