Natural habitat connectivity and organic management modulate pest dispersal, gene flow, and natural enemy communities.

The simplification and fragmentation of agricultural landscapes generate effects on insects at multiple spatial scales. As each functional group perceives and uses the habitat differently, the response of pest insects and their associated natural enemies to environmental changes varies. Therefore, landscape structure may have consequences on gene flow among pest populations in space. This study aimed to evaluate the effects of local and landscape factors, at multiple scales, on the local infestation, gene flow and broad dispersion dynamics of the pest insect Bemisia tabaci (Genn.) Middle East-Asia Minor 1 (MEAM-1, former biotype B) (Hemiptera: Aleyrodidae) and its associated natural enemies in a tropical agroecosystem. We evaluated the abundance of B. tabaci populations and their natural enemy community in 20 tomato farms in Brazil and the gene flow between farms from 2019 to 2021. Landscapes dominated by agriculture resulted in larger B. tabaci populations and higher gene flow, especially in conventional farms. A higher density of native vegetation patches disfavored pest populations, regardless of the management system. The results revealed that whitefly responds to intermediate spatial scales and that landscape factors interact with management systems to modulate whitefly populations on focal farms. Conversely, whitefly natural enemies benefited from higher amounts of natural vegetation at small spatial scales, while the connectivity between natural habitat patches was beneficial for natural enemies regardless of the distance from the focal farm. The resulting dispersion model predicts that the movement of whiteflies between farms increases as the amount of natural vegetation decreases. Our findings demonstrate that landscape features, notably landscape configuration, can mediate infestation episodes, as they affect pest insects and natural enemies in opposite ways. We also showed that landscape features interact with farm traits, which highlights the need for management strategies at multiple spatial scales. In conclusion, we demonstrated the importance of the conservation of natural areas as a key strategy for area-wide ecological pest management and the relevance of organic farming to benefit natural enemy communities in tropical agroecosystems.

Effects of Fabaceae and Poaceae Pollen Accessibility and Traits on the Pollinivory of Adult Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae).

Pollen is a food source for adult Chrysoperla externa (Hagen), whose larvae are biocontrol agents against pests. However, adults may face challenges in foraging for pollen due to differences in pollen accessibility and variability in pollen morphology and chemistry. In the laboratory, we investigated the ability of adult C. externa to consume pollen from flowers of Cajanus cajan, Canavalia ensiformis, Crotalaria juncea, Flemingia macrophylla, Avena strigosa, Pennisetum glaucum, Sorghum bicolor, and Zea mays, and we explored whether adults chose any of these pollens based on their quantitative and qualitative features. Cajanus cajan and F. macrophylla pollen were the only ones not consumed by adults when confined to flowers. Pollen removed from the preanthesis buds was offered simultaneously for 24 and 48 h. In both periods, adults consumed more of the medium-sized P. glaucum (with the second largest exine thickness) and large-sized Z. mays (with the thinnest exine) pollen, even though they had significantly less crude protein than Fabaceae pollen, whose sizes varied from medium (C. juncea, with the thickest exine) to large (C. ensiformis, whose exine thickness was equal to that of P. glaucum). Overall, adults consumed more Poaceae pollen than Fabaceae pollen, but the palynological features and the protein contents did not affect this choice. Our results highlighted that C. juncea, P. glaucum, S. bicolor and Z. mays are good pollen sources for adult C. externa and should be considered promising candidates in the selection of insectary plants to deploy in biocontrol programs aimed at the conservation of this lacewing.

Heteropteran Bugs Assemblage Associated to Organic Tomato Farms: Knowledge for Pest Management.

The suborder Heteroptera (Hemiptera) includes zoophagous and zoophytophagous species which conform diverse natural enemies' systems with potential to control several horticultural pests. In this study, we report the assemblage structure of heteropteran bugs species inhabiting open-field and greenhouse organic tomato crops and one common adjacent non-crop solanaceous plant, Solanum sisymbriifolium, in North Buenos Aires province, Argentina, aimed to select promissory biocontrol species. Biweekly direct inspection of selected plants was carried out during a 3-year period (2017-2019) to collect hemipteran nymphs and adults. As a result, nine species and morphospecies belonging to Berytidae (zoophytophagous), Lygaeidae (phytophagous), and Miridae (phytophagous and zoophytophagous) were found, with ≥ 75% of species belonging to the latter family. The zoophytophagous mirid Tupiocoris cucurbitaceus (Spinola) was the most frequent and dominant species in all sites studied. Among the phytophagous species, Nysius simulans Stål was mostly present in greenhouse crops. The community found in greenhouse tomato crops was more diverse than that registered in open-field crops. The characterization of the heteropteran complex in organic tomato farms provides basic knowledge necessary to design pest control strategies in the region studied.

Intercropping maize with brachiaria can be a double-edged sword strategy.

BACKGROUND: Intercropping is commonly implemented as a way of promoting sustainable agriculture. Some of the benefits of intercropping include improving resource-use efficiency and soil quality as well as promoting pest control. As for pest control, intercropping can often engender pest repellency/confusion and promote natural biological control. Nevertheless, intercropping is not always a win-win strategy for pest management, with chances of sometimes either favoring or hampering pests and their natural enemies. Brazilian farmers commonly row-intercrop maize with brachiaria with the intent of forming a grass pasture for the feeding of livestock after maize harvest. However, very little is known about whether this intercropping can influence key pests and natural enemies in the maize agroecosystem. The overall aim of this study was to investigate how multiple groups of maize pests and natural enemies respond in terms of temporal abundance to this intercropping. RESULTS: Defoliation caused by caterpillars was higher in the intercropping treatment. Intercropping appeared to promote Dalbulus maidis while hampering aphids and Diabrotica speciosa. In general, the abundance of natural enemies was favored by intercropping. There was a reduction in maize productivity (i.e. fresh weight) in the intercropping treatment. Most results were season dependent. CONCLUSION: We believe that by considering together the pros and cons of intercropping maize and brachiaria in terms of pest management and soil conservation/fertility, the benefits of implementing this intercropping shall still outweigh its potential challenges. Nevertheless, the results and ensuing recommendations should be considered under the context of time and arthropod species. © 2022 Society of Chemical Industry.

Diverse non-crop vegetation assemblages as banker plants for predatory mites in strawberry crop.

Non-crop plant diversity plays a fundamental role in the conservation of predatory mite (PM) and can be proposed as a banker plant system (BPS). BPSs provide plants that host natural enemies in greenhouses or field crops and may improve the efficiency of biological control. The aim of this study was to investigate if a diverse plant composition could be a suitable BPS for PMs in strawberry crops. A plant inventory characterized 22 species of non-crop plants harboring PMs. The most abundant PMs, in decreasing order, were Neoseiulus californicus, Neoseiulus anonymus, Euseius citrifolius, and Euseius concordis. PMs were randomly distributed among plants. We also found specific associations of Phytoseiidae species and phytophagous or generalist mites on plants. Due to this, four species were deemed suitable as banker plants: Capsicum sp., Leonurus sibiricus, Solanum americanum, and Urochloa mutica. Moreover, these plants combined a high PMs density and a low occurrence or absence of pest-mites. This study suggests shifting the traditional view that BPSs are composed of a limited number of species to use plant assemblages. This contributes to both conservation and augmentative biological control.

Dolichopodidae abundance in different cover crop species / Abundância de Dolichopodidae em diferentes espécies de adubos verdes

This study evaluated the Dolichopodidae abundance in different cover crop species. For this, the following species were used in treatments: Crotalaria (Crotalaria spectabilis), cowpea (Vigna unguiculata), sunflower (Helianthus annuus), castor bean (Ricinus communis) and buckwheat (Fagopyrum esculentum). The survey was carried out in a field during two seasons 2012/2013 (November/December to March) and 2013/2014 (October/November to February). The Dolichopodidae abundance were evaluated weekly using a sweep net and Moericke traps. In addition, the phytophagous abundance (Thysanoptera: Thripidae; Hemiptera: Aleyrodidae and Hemiptera: Aphididae) was quantified, to allow for an inference about density-dependence. In total, 13,987 long-legged flies (96.5% in Moericke traps) were captured, represented only by the species Condylostylus erectus Becker, 1922 (Diptera: Dolichopodidae). In general, the higher abundance of C. erectus was observed in buckwheat and cowpea. Regarding the phytophagous species, 48,371 individuals [Thripidae (77.5%), Aleyrodidae (20.2%), and Aphididae (2.5%)] were quantified and a clear correlation with the C. erectus population was not evidenced. Thus, these results suggested that buckwheat and cowpea make resources available to long-legged flies, as discussed in our research. Finally, the buckwheat and cowpea sowing are options to increase the abundance of C. erectus predator populations in agroecosystems.

O objetivo deste estudo foi avaliar a abundância de dolicopodideos em diferentes espécies de adubos verdes. Para isso, foram utilizados os seguintes tratamentos: crotalária (Crotalaria spectabilis), feijão-caupi (Vigna unguiculata), girassol (Helianthus annuus), mamona (Ricinus communis) e trigo mourisco (Fagopyrum esculentum). A pesquisa foi realizada em campo, durante os anos 2012/2013 (novembro/dezembro a março) e 2013/2014 (outubro/novembro a fevereiro). As avaliações foram realizadas semanalmente, e a abundância de Dolichopodidae foi monitorada com uso de rede de varredura e instalação de armadilhas Moericke. Adicionalmente, foi quantificada a infestação de insetos fitófagos (Thysanoptera: Thripidae; Hemiptera: Aleyrodidae e Hemiptera: Aphididae), para avaliar possível relação de denso-dependência. No total, foram capturados 13987 dolicopodídeos (96,5% em armadilha Moericke), representados pela espécie Condylostylus erectus Becker, 1922 (Diptera: Dolichopodidae). De modo geral, a maior abundância de C. erectus foi observada em trigo mourisco e feijão-caupi. Em relação aos fitófagos, foram quantificados 48371 indivíduos (Thripidae (77,5%), Aleyrodidae (20,2%) e Aphididae (2,5%)), e não foi evidenciada uma consistente correlação populacional com C. erectus. Desse modo, esses resultados sugerem que o trigo mourisco e o feijão-caupi disponibilizam recursos alimentares de interesse ao predador, conforme discutido no trabalho. Por fim, a semeadura de trigo mourisco e feijão-caupi são opções para incrementar a abundância do predador C. erectus no agroecossistema.

A parasitoid's dilemma between food and host resources: the role of volatiles from nectar-providing marigolds and host-infested plants attracting Aphidius platensis.

The use of nectar-producing companion plants in crops is a well-known strategy of conserving natural enemies in biological control. However, the role of floral volatiles in attracting parasitoids and effects on host location via herbivore-induced plant volatiles is poorly known. Here, we examined the role of floral volatiles from marigold (Tagetes erecta), alone or in combination with volatiles from sweet pepper plant (Capsicum annuum), in recruiting Aphidius platensis, an important parasitoid of the green peach aphid Myzus persicae. We also investigated whether marigold floral volatiles are more attractive to the parasitoid than those emitted by sweet pepper plants infested by M. persicae. Olfactometry assays indicated that floral volatiles attracted A. platensis to the marigold plant and are more attractive than sweet pepper plant volatiles. However, volatiles emitted by aphid-infested sweet pepper were as attractive to the parasitoid as those of uninfested or aphid-infested blooming marigold. The composition of volatile blends released by uninfested and aphid-infested plants differed between both blooming marigold and sweet pepper, but the parasitoid did not discriminate aphid-infested from uninfested blooming marigold. Volatile released from blooming marigold and sweet pepper shared several compounds, but that of blooming marigold contained larger amounts of fatty-acid derivatives and a different composition of terpenes. We discuss the potential implications of the aphid parasitoid attraction in a diversified crop management strategy.

Biological Control of Tephritid Fruit Flies in the Americas and Hawaii: A Review of the Use of Parasitoids and Predators.

Biological control has been the most commonly researched control tactic within fruit fly management programs. For the first time, a review is carried out covering parasitoids and predators of fruit flies (Tephritidae) from the Americas and Hawaii, presenting the main biological control programs in this region. In this work, 31 species of fruit flies of economic importance are considered in the genera Anastrepha (11), Rhagoletis (14), Bactrocera (4), Ceratitis (1), and Zeugodacus (1). In this study, a total of 79 parasitoid species of fruit flies of economic importance are listed and, from these, 50 are native and 29 are introduced. A total of 56 species of fruit fly predators occur in the Americas and Hawaii.

Terracing field slopes can concurrently mitigate soil erosion and promote sustainable pest management.

Convincing farmers to allot refuge areas for natural enemies is a challenge due to their fear of losing farming space. But, increasing the benefits beyond enhancing natural enemy conservation may further incentivize the adoption of refuge areas, which then would concomitantly favor biological control and other purposes. For example, the construction of terrace embankments on field slopes is essential to mitigate soil erosion; and this is better attained when vegetation occurs atop the terraces. Our insight is that these vegetated terraces can serve a dual purpose of preventing soil erosion as well as sheltering natural enemies and potentially diverting the attack of herbivorous pests. Therefore, in this two-year field study we assessed the abundance of natural enemies and pests as well as leaf damage and plant mass in maize plots cultivated between either vegetated or unvegetated terraces. The proportion of maize defoliation in the unvegetated-terrace treatment was about twice as high as the defoliation observed in the vegetated-terrace treatment during both years. The most abundant spontaneous vegetation occurring on the terraces comprised the grasses Panicum maximum Jacq. and Brachiaria decumbens (Stapf), which appeared to shelter herbivorous pests such as leafhoppers, spittlebugs and Chrysomelidae beetles as well as natural enemies. Specifically, a higher abundance of flying predators including wasps, ladybeetles and syrphids was observed in the vegetated-terrace treatment. Taken together, these results indicate the potential for vegetated terraces to concurrently mitigate soil erosion and promote pest control by means of enhancing natural enemy conservation as well as diverting pest attack.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta ) / Diversidade de parasitoides em Pimentão Orgânico (Capsicum annuum) associado com Manjericão (Ocimum basilicum ) e Cravo Amarelo (Tagetes erecta)

Abstract The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.

Resumo O pimentão (Capsicum annuum L.) é um dos vegetais mais importantes dentre os cultivados no Brasil. Muitos insetos pragas estão relacionados a esta cultura, comprometendo a quantidade e a qualidade do pimentão, tornando-se um grande problema para a produção. A diversificação vegetal é um dos principais componentes a serem manejados para suprimir as populações de pragas na produção orgânica, devido ao apoio a inimigos naturais das pragas. O manjericão ( Ocimum basilicum L.) e cravo amarelo (Tagetes erecta L.) são plantas atrativas e nutritivas para parasitoides, importantes candidatas em cultivos diversificados. Este trabalho avaliou os parasitoides atraídos pela associação de manjericão e cravo amarelo em cultivo de pimentão orgânico. O experimento foi composto por três tratamentos: a) monocultura de pimentão; B) pimentão consorciado com manjericão; C) pimentão consorciado com cravo amarelo. Foram coletadas amostras de parasitoides himenópteros durante 14 semanas. Os espécimes foram identificados até o menor nível de taxonomia possível. Foram coletados 268 indivíduos ao longo de 12 famílias e 41 táxons. Os tratamentos de monocultura, pimentão consorciado com manjericão e pimentão consorciado com cravo amarelo resultaram em 40, 98 e 130 indivíduos e riqueza de espécies de 24, 24 e 23, respectivamente. Além disso, os insetos de maior abundância coletados no manjericão e cravo amarelo, foram diferentes daqueles coletados na monocultura. Houve um aumento na abundância de parasitoides nas associações de pimentão com manjericão e cravo amarelo, proporcionando vantagens no uso da diversificação vegetal, podendo ser usada no manejo do pimentão orgânico.

Effects of Citrus Overwintering Predators, Host Plant Phenology and Environmental Variables on Aphid Infestation Dynamics in Clementine Citrus.

The Spirea citrus aphid, Aphis spiraecola Patch, and the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are key pests of clementine mandarines in the Mediterranean basin. Severity of aphid infestations is determined by environmental variables, host plant phenology patterns, and the biological control exerted by their associated natural enemies. However, there is no information about the role these limiting and regulating factors play. Aphid densities, citrus phenology, and associated predators that overwinter in the crop were monitored weekly throughout two flush growth periods (February to July) in four clementine mandarin groves; relationships between these parameters and environmental variables (temperature and precipitation) were studied. Our results show exponential increase in aphid infestation levels to coincide with citrus phenological stages B3 and B4; shoots offer more space and nutritional resources for colony growth at these stages. Duration of these phenological stages, which was mediated by mean temperature, seems to importantly determine the severity of aphid infestations in the groves. Among those studied, the micro-coccinellids, mostly Scymnus species, were the only group of predators with the ability to efficiently regulate aphid populations. These natural enemies had the highest temporal and spatial demographic stability. Aphid regulation success was only achieved through early presence of natural enemies in the grove, at the aphid colonization phase. Our results suggest that conservation strategies aimed at preserving and enhancing Scymnus sp. populations may make an important contribution to the future success of the biological control of these key citrus pests.

Contribution of predation to the biological control of a key herbivorous pest in citrus agroecosystems.

Biological control has traditionally simplified the view of trophic relationships between herbivorous pests and their natural enemies in agriculture. The success or failure of this pest management strategy is still mainly attributed to the ability of a few key natural enemies to suppress the pest density. For example, successful regulation of the California red scale (Aonidiella aurantii), a key citrus pest, is generally credited to specific parasitoids of the Aphytis genus. Currently, research is revealing how herbivore regulation in agroecosystems can be alternatively achieved with a greater number of trophic associations within the system. The goals of the present study were as follows: i) to unravel species-specific trophic links between A. aurantii and its natural enemies in citrus agroecosystems, and ii) to assess their contribution to control of A. aurantii. Predation and parasitism of this herbivorous pest were assessed through exclusion experiments. Species-specific trophic links between this herbivorous pest and its natural enemies were studied using gut-content analysis of field-collected predators employing prey-specific DNA molecular markers. Relative predation rates of the species involved in A. aurantii regulation were estimated. Predation was found to be the main biotic component of A. aurantii mortality, causing reductions of more than 75% in recently settled cohorts. Aonidiella aurantii DNA was detected in the digestive system of 11 species of predators. Generalist and stenophagous predators, mainly associated with other citrus pests such as aphids, proved to be the most important biological control agents of this pest. Complex trophic relationships, such as apparent competition between two key citrus pests, were revealed. The present study highlights the role of predation as biotic mortality factor of key pests in perennial agroecosystems, wherein it is a rich complex of indigenous or naturalized generalist predators that are primarily responsible for this mortality. The results herein presented may therefore offer another perspective on the biological control of one of the key world-wide citrus pests, at least in those regions where specific parasitoids are not able to successfully regulate the scale populations.

Brazilian Legislation Leaning Towards Fast Registration of Biological Control Agents to Benefit Organic Agriculture.

Brazil is one of the main users of chemical pesticides in the world. These products threaten human and environmental health, and many of them are prohibited in countries other than Brazil. This paradigm exists in contrast with worldwide efforts to make the need for food production compatible with biodiversity conservation, preservation of ecosystem services, and human health. In this scenario, the development of sustainable methods for crop production and pest management such as organic agriculture and biological control are necessary. Herein, we describe how the process of registration of natural enemy-based products in organic agriculture is simpler and faster than the conventional route of chemical insecticides and can favor the development of the biological control market in Brazil. Since the regulatory mechanisms have been established in Brazil for organic agriculture, the number of biological control products registered has increased exponentially. Today, 50 companies and associations are marketing 16 species/isolates and 95 natural enemy-based products. Although this scenario presents a series of new opportunities to increase and stimulate a more sustainable agriculture in the country, biological control is not always aligned with the aims and philosophy of organic agriculture and agroecology. Therefore, we also argue that new research efforts are needed on understanding how conservation biological control strategies can be integrated with augmentation biological control to promote a sustainable agriculture under the concepts of organic agriculture and agroecology.

Current Strategies and Future Outlook for Managing the Neotropical Tomato Pest Tuta absoluta (Meyrick) in the Mediterranean Basin.

The invasion of new regions by exotic pests has been more than ever a critical issue that warrants coordinated international actions to manage established populations and prevent further spreading. Invasive insects can undermine the ecological equilibrium of both natural and agricultural ecosystems. Moreover, increasing temperatures due to climatic change exacerbate this problem by allowing pests to further reach regions previously considered unsuitable. The tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera) is an exotic pest native to Peru that has spread beyond Neotropical America. In Europe, its occurrence was reported in Spain in 2006, and thereafter, it has spread throughout the Mediterranean Basin and further into Africa and part of Asia. While T. absoluta can cause losses to tomato production all over the globe, the differences in each invaded region (e.g., climate, vegetation) may affect its population dynamics and, consequently, management protocols. Therefore, the main intent of this forum paper is to explore how European growers and researchers are dealing with T. absoluta in the Mediterranean area. As for many other invasive pests, the best approach has been the adoption of integrated pest management (IPM). Specifically, the integration of biological control agents (e.g., mirid predators and egg parasitoids), microbial insecticides (i.e., Bacillus thuringiensis), selective chemical insecticides, and sex pheromone-based control has proven adequate, especially in tomato greenhouses. Nonetheless, some of the challenges ahead include the development of resistant tomato cultivars, the management of wild vegetation and companion plants to optimize the conservation of natural enemies and their effectiveness at the crop level, the management of insecticide resistance, and the improvement of sex pheromone-based tactics.

Natural factors regulating mustard aphid dynamics in cabbage.

Lipaphis erysimi (L.) Kaltenbach (Hemiptera: Aphididae) is one of the most important pests of brassica crops, mainly causing losses due to sap sucking, toxin injection and viral transmission. Knowledge about the main natural factors that regulate populations of this pest, as well as its critical mortality stage, is crucial for the development of integrated pest management of L. erysimi. Here, we determined the critical stage and key mortality factors for L. erysimi in cabbage using an ecological life table. Causes of mortality at each stage of L. erysimi development were monitored daily in the field for seven seasons. From the experimental data, we determined the key factor and critical stage of mortality through correlation and regression analyses. The nymphal stage, especially first instar nymphs, was critical for L. erysimi mortality. The key mortality factors were, in descending order of importance, physiological disturbances and predation by Syrphidae, Coccinellidae and Solenopsis ants. Therefore, control measures should target early stages of L. erysimi and the use of cabbage cultivars that have negative effects against L. erysimi may be a promising strategy for its management. Our results may be useful for plant geneticists who could develop new cabbage cultivars based on these findings. In addition, conservation measures of the main predators of L. erysimi may contribute to the natural control of this pest.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta ) / Diversidade de parasitoides em Pimentão Orgânico (Capsicum annuum) associado com Manjericão (Ocimum basilicum ) e Cravo Amarelo (Tagetes erecta

The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.(AU)

O pimentão (Capsicum annuum L.) é um dos vegetais mais importantes dentre os cultivados no Brasil. Muitos insetos pragas estão relacionados a esta cultura, comprometendo a quantidade e a qualidade do pimentão, tornando-se um grande problema para a produção. A diversificação vegetal é um dos principais componentes a serem manejados para suprimir as populações de pragas na produção orgânica, devido ao apoio a inimigos naturais das pragas. O manjericão ( Ocimum basilicum L.) e cravo amarelo (Tagetes erecta L.) são plantas atrativas e nutritivas para parasitoides, importantes candidatas em cultivos diversificados. Este trabalho avaliou os parasitoides atraídos pela associação de manjericão e cravo amarelo em cultivo de pimentão orgânico. O experimento foi composto por três tratamentos: a) monocultura de pimentão; B) pimentão consorciado com manjericão; C) pimentão consorciado com cravo amarelo. Foram coletadas amostras de parasitoides himenópteros durante 14 semanas. Os espécimes foram identificados até o menor nível de taxonomia possível. Foram coletados 268 indivíduos ao longo de 12 famílias e 41 táxons. Os tratamentos de monocultura, pimentão consorciado com manjericão e pimentão consorciado com cravo amarelo resultaram em 40, 98 e 130 indivíduos e riqueza de espécies de 24, 24 e 23, respectivamente. Além disso, os insetos de maior abundância coletados no manjericão e cravo amarelo, foram diferentes daqueles coletados na monocultura. Houve um aumento na abundância de parasitoides nas associações de pimentão com manjericão e cravo amarelo, proporcionando vantagens no uso da diversificação vegetal, podendo ser usada no manejo do pimentão orgânico.(AU)

Cascading effects of combining synthetic herbivore-induced plant volatiles with companion plants to manipulate natural enemies in an agro-ecosystem.

BACKGROUND: Whether tactics to manipulate natural enemies in agro-ecosystems enhance their ecosystem function and services remains debatable. We conducted field experiments in 2015-2016 to test the hypothesis that attraction of natural enemies to herbivore-induced plant volatiles (HIPVs), alone or in combination with companion plants, increases crop productivity. Our treatments consisted of bean plants alone or baited with methyl salicylate (MeSA; an HIPV), or combined with coriander (a companion plant), or with both MeSA and coriander. Numbers of arthropods were visually sampled in each treatment. Sentinel aphids were used to measure ecosystem function (i.e. predation). Plant damage and biomass, and the number and weight of pods and seeds, were measured as a proxy for ecosystem services. RESULTS: MeSA and coriander, when alone or combined, increased the abundance of insect predators from six families, reduced herbivore (e.g. spider mite and thrips) populations, and increased aphid predation. MeSA and coriander also reduced damage by spider mites. MeSA with or without coriander did not, however, increase crop biomass or any yield parameters. CONCLUSIONS: MeSA alone or combined with coriander attracted different predator communities, altered pest communities, and reduced damage; however, these results did not cascade down to improve crop productivity. © 2018 Society of Chemical Industry.

Problems Inherent to Augmentation of Natural Enemies in Open Agriculture.

Augmentation biological control has successfully replaced a lot of insecticide use in 'closed system' agriculture (e.g., greenhouses). The profitable commercialization of biocontrol agents in greenhouses has created an incentive to expand markets for mass-reared beneficial insects into open agricultural systems, often without sufficient scientific justification. However, the semi-contained nature of greenhouse culture is often critical to the success of augmentation and can serve to mask potential pitfalls and intrinsic limitations of this approach in open systems. Factors contributing to greenhouse successes include the reduced biological diversity of contained agroecosystems, the prevention of agent dispersal, the ability to maintain environmental conditions within a range favorable for the agent, the exclusion of competitors and natural enemies of the agent that might otherwise diminish its efficacy, and the absence of alternative prey/hosts that could divert predation/parasitism from the target pest. There are also problems arising from collection of source material from locally adapted populations, and the inadvertent imposition of artificial selection in the course of laboratory rearing. Besides highlighting these pitfalls, this paper aims to encourage more consideration of conservation approaches prior to investment in augmentation programs which entice farmers into perpetual cycles of 'rear and release.' I argue that although augmentation can benefit agriculture whenever it replaces pesticide applications, it does not constitute an ecologically sustainable solution because it requires continued inputs, and it can distract research attention away from more sustainable objectives. Sustainable biological control is best achieved through modifications to cultural practices that increasingly 'naturalize' agroecosystems, thus facilitating the natural recruitment and persistence of beneficial arthropod fauna, combined with habitat management geared to increasing overall plant and arthropod diversity in the agroecosystem.

Pollen Ingestion by Chrysoperla externa (Hagen) Adults in a Diversified Organic Agroecosystem.

Chrysoperla externa (Hagen) larvae prey on pest insects and mites in agroecosystems, and adults mainly feed on pollen, nectar, and honeydew. Therefore, preserving this lacewing in crop systems depends on having plants that provide these resources. The objectives of this research were to identify pollen grains ingested by Ch. externa adults collected in a diversified organic agroecosystem and to evaluate whether there is a difference in the amount of ingested pollen grains between males and females. The adults of Ch. externa were collected in four different crops during 13 months in Seropédica, state of Rio de Janeiro, Brazil, using a collecting net. The adults were killed and underwent acetolysis, in order to recover the pollen in the gut. A total of 37,441 pollen grains from 19 Angiospermae families were found, besides 16 Pteridophyte spores. Among the recognized pollen grains, those of Poaceae were the majority, both in frequency of occurrence (87.5%) and in quantity (33496), and were found and recovered in every month of collection. Females and males ingested, respectively, 71.9 and 28.1% of the total number of Angiospermae pollen grains consumed by both sexes. The highest number of Poaceae pollens was obtained from the females (72.1% of the total number of Poaceae pollen, recovered from females + males). Taken as a whole, this study showed that adults of Ch. externa find possibilities to maintain throughout the year, in different crops, but the main source of pollen to males and females was Poaceae plants.

Parasitoids diversity in organic Sweet Pepper (Capsicum annuum) associated with Basil (Ocimum basilicum) and Marigold (Tagetes erecta )

Abstract The sweet pepper (Capsicum annuum L.) is one of the most important crops in Brazilian farming. Many insect are related to this crop, compromising the quantity and quality of the fruit, representing a production problem. Vegetable diversification is one of the main elements that can be managed for suppressing undesirable insect populations in organic production, once that supports the presence of natural enemies. The basil Ocimum basilicum L. and the marigold Tagetes erecta L. are attractive and nutritious plants for parasitoids, being important candidates for diversified crops. This study evaluated the parasitoids attracted by the association of basil and marigold to organic sweet pepper crop. The experiment comprised three treatments: a) sweet pepper monoculture; b) sweet pepper and basil intercropping; c) sweet pepper and marigold intercropping. Hymenopteran parasitoids were collected over 14 weeks. 268 individuals from 12 families and 41 taxa were collected. Sweet pepper monoculture, sweet pepper-basil intercropping, and sweet pepper-marigold intercropping hosted 40, 98, and 130 individuals and richness of 24, 24, and 23, respectively. Furthermore, the insects of greater abundance in the basil and marigold were different to those collected in the monoculture. The number of parasitoids increased in the associations of sweet pepper with basil and marigold, providing advantages in the use of vegetable diversification for the organic pepper crops management.

Resumo O pimentão (Capsicum annuum L.) é um dos vegetais mais importantes dentre os cultivados no Brasil. Muitos insetos pragas estão relacionados a esta cultura, comprometendo a quantidade e a qualidade do pimentão, tornando-se um grande problema para a produção. A diversificação vegetal é um dos principais componentes a serem manejados para suprimir as populações de pragas na produção orgânica, devido ao apoio a inimigos naturais das pragas. O manjericão ( Ocimum basilicum L.) e cravo amarelo (Tagetes erecta L.) são plantas atrativas e nutritivas para parasitoides, importantes candidatas em cultivos diversificados. Este trabalho avaliou os parasitoides atraídos pela associação de manjericão e cravo amarelo em cultivo de pimentão orgânico. O experimento foi composto por três tratamentos: a) monocultura de pimentão; B) pimentão consorciado com manjericão; C) pimentão consorciado com cravo amarelo. Foram coletadas amostras de parasitoides himenópteros durante 14 semanas. Os espécimes foram identificados até o menor nível de taxonomia possível. Foram coletados 268 indivíduos ao longo de 12 famílias e 41 táxons. Os tratamentos de monocultura, pimentão consorciado com manjericão e pimentão consorciado com cravo amarelo resultaram em 40, 98 e 130 indivíduos e riqueza de espécies de 24, 24 e 23, respectivamente. Além disso, os insetos de maior abundância coletados no manjericão e cravo amarelo, foram diferentes daqueles coletados na monocultura. Houve um aumento na abundância de parasitoides nas associações de pimentão com manjericão e cravo amarelo, proporcionando vantagens no uso da diversificação vegetal, podendo ser usada no manejo do pimentão orgânico.