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See detailWheat (Triticum aestivum L.)-based intercropping systems for biological pest control: a review
Chevalier Mendes Lopes, Thomas ULg; Hatt, Séverin ULg; Xu, Qinxuan et al

in Pest Management Science (in press)

BACKGROUND: Wheat (Triticum aestivum L.) is one of the most cultivated crops in temperate climates. As its pests are mainly controlled with insecticides which are harmful to the environment and human ... [more ▼]

BACKGROUND: Wheat (Triticum aestivum L.) is one of the most cultivated crops in temperate climates. As its pests are mainly controlled with insecticides which are harmful to the environment and human health, alternative practices such as intercropping have been studied for their potential to promote biological control. Based on the published literature, this study aimed to review the effect of wheat-based intercropping systems on insect pests and their natural enemies. RESULTS: Fifty original research papers were obtained from a systematic search of the peer-reviewed literature. Results from a vote-counting analysis indicated that, in the majority of studies, pest abundance was significantly reduced in intercropping systems compared with pure stands. However, the occurrence of their natural enemies as well as predation and parasitism rates were not significantly increased. The country where the studies took place, the type of intercropping, and the crop that was studied in the association had significant effects on these results. CONCLUSION: These findings show that intercropping is a viable practice to decrease insecticide use in wheat production systems. Nevertheless, other practices could be combined with intercropping to favour natural enemies and enhance pest control. [less ▲]

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See detailDevelopment of alternative methods to control aphids (Hemiptera: Aphididae): from wheat-pea intercropping to the use of semiochemical dispensers
Chevalier Mendes Lopes, Thomas ULg

Doctoral thesis (2016)

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of ... [more ▼]

Increasing the sustainability of food production is a major challenge in today’s agriculture. Several practices can be implemented to reduce the use of external inputs such as agrochemicals. In terms of insect pest control, the concept of integrated pest management (IPM) has been exploited to minimize the application of chemical insecticides. The idea is to limit pest infestations while promoting their control by natural enemies. One possibility is to increase within crops plant diversity namely by intercropping. Semiochemical dispensers may also be used to attracted natural enemies into crops. Focusing on wheat (Triticum aestivum Linnaeus), several types of intercropping can be practiced with variable effects on pests and natural enemies. This PhD thesis focuses on the potential of wheat-pea (Pisum sativum Linnaeus) intercropping as a way to reduce aphid (Hemiptera: Aphididae) infestations. We firstly assessed the diversity of aphid and their parasitoid species in wheat and pea fields using yellow pan traps and in situ observations on plants. Whether several aphid species were trapped, only Sitobion avenae (Fabricius), Metopolophium dirhodum (Walker), Rhopalosiphum padi (Linnaeus) and Acyrthosiphon pisum (Harris) were found on wheat tillers and pea plants respectively. Regarding parasitoids, some species can use wheat and/or pea aphids as hosts. The first Belgian parasitoid species checklist was established, with the inclusion of four Aphidiinae (Hymenoptera: Braconidae) and three Aphelinus (Hymenoptera: Aphelinidae) species as new records. In terms of abundance, we firstly compared the effect of two types of wheat-pea intercropping (mixed and alternate strip cropping) on aphids and their natural enemies with pure stands of both crops. The mixture was particularly efficient to reduce pea aphid populations, while alternate strips were more suitable for the control of wheat aphids. However, natural enemies were more abundant in the pure stands, showing that additional methods may be needed to attract them more efficiently. One possibility is the use of semiochemicals dispensers. In another field study, we combined a wheat-pea mixture with methyl salicylate (MeSA) dispensers. This substance was selected due to its known attractive effect towards some aphid beneficials. Even though adult hoverflies (Diptera: Syrphidae) were not particularly attracted by the mixture combined with MeSA dispensers, they may have stimulated their oviposition behaviour. Also, mummified aphids were significantly more abundant in the pure stand of pea compared with the mixture (with and without MeSA). However, parasitism rates did not differ significantly between treatments. Beneficial effects of wheat-pea intercropping were clearly demonstrated for aphid control. Other agronomic aspects make this practice particularly interesting in low-input farming systems. These are discussed, along the limitations related to the use semiochemicals in field conditions. Perspectives for further research works are also proposed. [less ▲]

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See detailEffect of wheat-based intercropping systems on pests and natural enemies: a review with a special focus on China
Hatt, Séverin ULg; Chevalier Mendes Lopes, Thomas ULg; Xu, Qinxuan et al

Conference (2016, April 16)

Intercropping is a farming practice consisting of cultivating at least two plant species simultaneously in the same field, but without necessarily sowing and/or harvesting them at the same time. By ... [more ▼]

Intercropping is a farming practice consisting of cultivating at least two plant species simultaneously in the same field, but without necessarily sowing and/or harvesting them at the same time. By increasing plant diversity at the field scale, intercropping may be an efficient method to control insect pests and support natural enemies on the associated crops. We performed a systematic research of the peer-reviewed literature which studied the effect of intercropping systems on pests and natural enemies, compared to pure stands. The research was restricted to wheat-based systems, as it is an important crop worldwide, and the main one in Northern China. A total of fifty research papers were obtained from the literature search. Results from a vote-counting analysis, using binomial tests, indicated that pest abundance was significantly reduced in intercropping systems compared with pure stands, but their natural enemies were not particularly favoured (i.e., predators and parasitoids). Among these papers, 23 were studies from China. There, wheat was associated with cotton in relay-intercropping, as well as alfalfa, chili peppers, fava bean, garlic, mung bean, oilseed rape and pea in strip-cropping. Aphids were systematically reduced and natural enemies (i.e., predators and parasitoids) significantly favoured in intercropping systems compared to pure stands. This study shows that intercropping is a viable practice to biologically control pests, and potentially support natural enemies, especially in China. Therefore it can be seen as a viable method to reduce insecticide use in wheat production systems. [less ▲]

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See detailInventaire et mise en collection d’espèces de pucerons et de parasitoïdes collectés en grandes cultures, et premier enregistrement de Metopolophium frisicum (Hille Ris Lambers 1947) et Acyrthosiphon primulae (Theobald 1913) (Hemiptera: Aphididae) en Belgique
Chevalier Mendes Lopes, Thomas ULg; Hatt, Séverin ULg; Starý, Petr et al

in Entomologie Faunistique = Faunistic Entomology (2016), 69

The purpose of this study was to identify aphid and parasitoid species that were collected in wheat and pea crops situated in Gembloux (Belgium), and conserve them into collections. To do so, yellow traps ... [more ▼]

The purpose of this study was to identify aphid and parasitoid species that were collected in wheat and pea crops situated in Gembloux (Belgium), and conserve them into collections. To do so, yellow traps (von Moericke) were used during 2012, 2013 and 2014 growing seasons. Fifty-two aphid species were identified and conserved in the entomological Conservatory of Gembloux. Among them, Metopolophium frisicum (Hille Ris Lambers 1947) and Acyrthosiphon primulae (Theobald 1913) were officially referenced for the first time in Belgium. Moreover, a collection composed by 16 parasitoid species was created. Their interest for biological control, as well as the methods that are studied in the laboratory of functional and evolutionary Entomology from Gembloux Agro-Bio Tech (University of Liège) to promote their presence in crops are discussed. [less ▲]

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See detailChecklist of Aphidiinae (Hymenoptera: Braconidae) and Aphelinus (Hymenoptera: Aphelinidae) species from Belgium with respectively four and three new records
Chevalier Mendes Lopes, Thomas ULg; Libert, Pierre-Nicolas; Starý, Petr et al

in Zootaxa (2016), 4092(4)

Aphid parasitoids have good potential for crop protection. However, they have been poorly studied in Belgium, especially in terms of species diversity. Therefore, the aim of this work was to establish the ... [more ▼]

Aphid parasitoids have good potential for crop protection. However, they have been poorly studied in Belgium, especially in terms of species diversity. Therefore, the aim of this work was to establish the first checklist for the country. To complete the list, aphid parasitoids were sampled in wheat and pea fields near Gembloux (Belgium), in 2013 and 2014. Among the identified species, Aphelinus asychis Walker, Aphelinus daucicola Kurdjumov, Aphelinus fusciscapus (Förster), Aphidius asteris Haliday, Aphidius eadyi Starý, Gonzalez & Hall, Praon barbatum Mackauer, and Trioxys auctus (Haliday) were recorded for the first time in Belgium. Thirty-two Aphidiinae and seven Aphelinus species were included in the checklist. It is hoped this study will stimulate further research, as species diversity is still low compared with neighbouring countries. [less ▲]

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See detailSpecies diversity and abundance of aphids and their natural enemies in a crop association
Chevalier Mendes Lopes, Thomas ULg; Hatt, Séverin ULg; Starý, Petr et al

Poster (2015, November)

Crop associations can be efficient to reduce aphid populations, by disrupting the visual and olfactory location of host plants. However, increasing the chemical and structural complexity of vegetation can ... [more ▼]

Crop associations can be efficient to reduce aphid populations, by disrupting the visual and olfactory location of host plants. However, increasing the chemical and structural complexity of vegetation can also decrease the searching efficiency of predators and parasitoids, which are not always more abundant in complex habitats. Using attractive semiochemicals such as methyl salicylate (MeSA) combined with a crop association seems promising to maximise aphid control. We compared the abundances of aphids and their natural enemies between a wheat-pea mixture (with and without MeSA) and pure stands, using yellow traps and observations on plants. Significantly higher numbers of pea aphids (Acyrthosiphon pisum) were observed in the pure stand of pea compared with the mixture (with and without MeSA) in 2013 and 2014. Concerning aphid natural enemies, hoverfly larvae abundance was not significantly different between treatments in both years. Parasitoid mummies were significantly more abundant in the pure stand of pea compared with the mixture (with and without MeSA) in 2014. Fifty-two aphid species were collected in yellow traps, as well as 12 Aphidiinae and four Aphelinus species. Acyrthosiphon primulae, Aphelinus daucicola, Aphelinus fusciscapus, Aphidius asteris, Aphidius eadyi, Metopolophium frisicum, Praon barbatum, and Trioxys auctus were recorded for the first time in Belgium. Besides determining the effects of a wheat-pea mixture (with or without MeSA) on aphid control, this study contributed to increase the knowledge on aphid and their parasitoid diversity in Belgium, by recording new species and establishing the first Aphidiinae and Aphelinus national checklist. [less ▲]

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See detailWildflowers sown at field margins have positive and negative effects on pests and parasitoids
Hatt, Séverin ULg; Uyttenbroeck, Roel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, September 03)

Wildflower strips are sown at field margins throughout Europe to support insect conservation in agricultural areas. Among other insects, parasitoids may favor a biological regulation of pests. On an ... [more ▼]

Wildflower strips are sown at field margins throughout Europe to support insect conservation in agricultural areas. Among other insects, parasitoids may favor a biological regulation of pests. On an experimental field of the research platform AgricultureIsLife in Gembloux (University of Liège, Belgium), three replications of five wildflower seed mixtures were sown in strips adjacent to crops in spring 2013. Insect pests and their parasitoids were pan-trapped in spring 2014 in both wildflower strips and oilseed rape crops and identified at the species level. Flower species and cover were monitored in the strips using 1 m² quadrats, before mowing. Meligethes spp. were found abundantly in crops when oilseed rape was blooming. Meligethes’ parasitoids occurred later and their abundance was positively correlated with that of Meligethes in the flower strips. At the crop ripening stage, weevils Ceutorhynchus spp. occurred and were followed by an increase in abundance of their parasitoids in both crops and flowers. Positive as well as negative correlations were found between the abundance of these pests, their parasitoids and different flower species blooming at this time. The link between these results with flower species’ functional traits will be discussed. [less ▲]

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See detailDoes combining a wheat and pea mixture with methyl salicylate reduces aphid populations in both crops?
Chevalier Mendes Lopes, Thomas ULg; Fassotte, Bérénice ULg; Hatt, Séverin ULg et al

Conference (2015, August 25)

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the ... [more ▼]

Aphids are important pests of wheat and pea. Among the alternative methods to control them with less reliance on insecticides, crop associations already proved to be efficient. However, if increasing the chemical and structural complexity of vegetation can disrupt their host plants location, the searching efficiency of predators and parasitoids can also be reduced. Therefore, these beneficials may not always be more abundant in such systems. Combining crop associations with attractive semiochemicals for natural enemies can be interesting to solve this problem. In this research, we compared the effect of a wheat and pea pure stand, wheat and pea mixture, and wheat and pea mixture combined with methyl salicylate (MeSA) formulated in alginate gel beads, on the abundance and diversity of aphids and their natural enemies. These were weekly observed on plants during 2013 and 2014 growing seasons. Over these two years, significantly higher numbers of pea aphids (Acyrthosiphon pisum (H.)) were observed in the pure stand of pea compared with both mixtures (with and without MeSA). No significant differences were observed between treatments for wheat aphids (Sitobion avenae (F.), Metopolophium dirhodum (W.) and Rhopalosiphum padi (L.)), which were significantly less abundant than pea aphids. Aphid natural enemies were mainly observed on pea plants. Hoverfly larvae abundance was not significantly different between treatments during both years. The same phenomenon occurred with hoverfly pupae in 2013, while these were significantly more abundant in both mixtures compared with the pure stand in 2014. However, their number did not differ significantly between the mixture with and without MeSA. Few ladybirds and lacewings were observed. No significant differences were observed between treatments for parasitoid mummies in 2013. Their abundance was significantly higher in the pure stand of pea compared with both mixtures in 2014. Results from this study show that mixing wheat and pea is an efficient method to maintain aphid populations at a very low level on pea. The use of MeSA did not show significant effects on natural enemies. However, mixing these crops may be enough to reduce aphid populations under an acceptable threshold. [less ▲]

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See detailEfficiency of pheromone-based formulations against phytophagous pests
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

Conference (2015, May 19)

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or ... [more ▼]

Innovative integrated pest management methods are needed to overcome market withdrawal of synthetic pesticides. Therefore, the identification of environment-friendly bio-products carrying direct or indirect biocide activity is one promising alternative option. Our researches focus on the identification of appropriate formulations releasing volatile organic compounds that are attractant for natural enemies of insect pests. However, the elaboration of slow-release devices that ensure stable and controlled release of active volatile compounds is quite challenging. Here, we developed a formulation based on E-β-farnesene and (-)-β-caryophyllene, these two semiochemicals having strong attractive potential on aphid natural enemies including lady beetles and hoverflies. Both compounds were encapsulated together in alginate gel beads. The blend efficiency was first evaluated through laboratory assays, and then in wheat and broad bean fields, by considering the abundance and diversity of aphids and their natural enemies. [less ▲]

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See detailAssociations of Wheat with Pea Can Reduce Aphid Infestations
Chevalier Mendes Lopes, Thomas ULg; Bodson, Bernard ULg; Francis, Frédéric ULg

in Neotropical Entomology (2015)

Increasing plant diversity within crops can be beneficial for pest control. In this field study, the effects of two wheat and pea associations (mixed cropping and strip cropping) on aphid populations were ... [more ▼]

Increasing plant diversity within crops can be beneficial for pest control. In this field study, the effects of two wheat and pea associations (mixed cropping and strip cropping) on aphid populations were compared with pure stands of both crops by observations on tillers and plants. Pea was more susceptible to infestations than wheat. As expected, the density of aphid colonies was significantly higher in pure stands during the main occurrence periods, compared with associations. Additionally, flying beneficials, such as not only aphidophagous adult ladybirds but also parasitoid, hoverfly and lacewing species that feed on aphids at the larval stage, were monitored using yellow pan traps. At specific times of the sampling season, ladybirds and hoverflies were significantly more abundant in the pure stand of pea and wheat, respectively, compared with associations. Few parasitoids and lacewings were trapped. This study showed that increasing plant diversity within crops by associating cultivated species can reduce aphid infestations, since host plants are more difficult to locate. However, additional methods are needed to attract more efficiently adult beneficials into wheat and pea associations. [less ▲]

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See detail10. Perspectives - 1. La Lutte contre les pucerons grâce aux odeurs: développement d'une formulation phéromonale
Fassotte, Bérénice ULg; Vandereycken, Axel ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Watillon, Bernard; Bodson, Bernard (Eds.) Livre Blanc Céréales (2015, February 25)

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See detailDo wildflower strips favor insect pest populations at field margins ?
Hatt, Séverin ULg; Uyttenbroeck, Roel ULg; Chevalier Mendes Lopes, Thomas ULg et al

in Agriculture and Agricultural Science Procedia (2015)

Reducing pesticide use is one the major issues of today’s agriculture. Among other possibilities, attracting and conserving pest natural enemies in agricultural landscapes by providing them habitats is ... [more ▼]

Reducing pesticide use is one the major issues of today’s agriculture. Among other possibilities, attracting and conserving pest natural enemies in agricultural landscapes by providing them habitats is promising. Wildflower strips (WFS) sown at field margins are one of these potential habitats. They are known to attract and conserve a large diversity of insects, as they provide them food resources such as pollen and nectar, as well as shelter and overwintering sites. However, the risk of attracting insect pests at field margins may represent an obstacle to their adoption by farmers. Conversely, it would be interesting if such WFS could play the role of pest trap crops. In an experimental field sown with WFS intercropped with oilseed rape (OSR) (Brassica napus L.), its coleopteran pests were trapped in both WFS and OSR using yellow pan traps between April and June 2014. More than 130 000 Meligethes spp., Ceutorhynchus spp. and Psylliodes chrysocephalla (L.) adults were trapped. Meligethes spp., Ceutorhynchus spp. were significantly more abundant in the OSR compared with WFS when adults emerged and populations reached their abundance peak. Before and between these periods, the few adults trapped were significantly more abundant in the WFS compared with the OSR. Concerning P. chrysocephala, too few individuals were caught for analysis. Results showed that OSR was more attractive than WFS when coleopteran pests were abundant. In this study, WFS sown for insect conservation may neither favour insect pest conservation at field margin, nor be considered as trap crops. [less ▲]

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See detailEffets de deux associations culturales à base de blé sur les populations de pucerons (Homoptera: Aphididae) et d’auxiliaires aphidiphages: étude préliminaire menée en Chine
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Honba, David et al

in Entomologie Faunistique = Faunistic Entomology (2014), 67

Crop associations have several advantages when plant species and crop production methods, including harvesting, are well selected. This preliminary study was conducted in the Shandong province (China) to ... [more ▼]

Crop associations have several advantages when plant species and crop production methods, including harvesting, are well selected. This preliminary study was conducted in the Shandong province (China) to better characterize the effect of wheat (Triticum aestivum L.)/oilseed rape (Brassica napus L.) and wheat/pea (Pisum sativum L.) associations on the aphid and aphidophagous beneficial populations. Aphids observed on wheat tillers were significantly more abundant in the pure stand of wheat during the two weeks prior to their population peak, compared with crop associations. Considering the aphidophagous beneficials, significantly more ladybirds were observed in the associations, compared with the pure stand during their abundance peak. Yellow pan traps were also used to assess the diversity and abundance of adult beneficial species. The parasitoid species Aphidius gifuensis (Ashmead) was prevalent. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species. This study contributes to better understand the potential of crop associations with wheat as a sustainable method to control aphid populations in this region of China. [less ▲]

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See detailImpacts d’une association culturale de pois et de pommes de terre sur les pucerons et auxiliaires aphidiphages en Chine
Bosquée, Emilie ULg; Chevalier Mendes Lopes, Thomas ULg; Serteyn, Laurent ULg et al

in Entomologie Faunistique = Faunistic Entomology (2014), 67

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the ... [more ▼]

Crop associations can have beneficial effects on the control of insect pests. This study was conducted in the Shandong province (China) to assess the impact of potatoes and peas association on the populations of aphids and their natural enemies. Observations on potato plants and trapping (yellow pan traps) were performed. During the season, the degree of infestation didn’t differ significantly between the association and the pure stand. However, one week after the aphids abundance peak, predators and parasitoid mummies were significantly more abundant in the association compared with the pure stand. Trapping give a more general idea about the richness and diversity of adult natural enemies present in the environment. The parasitoid specie Aphidius gifuensis (Ashmead) was the most abundant among beneficials. Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were prevalent among predators. Few hoverflies and lacewings were trapped. This study contributes to better evaluate the potential of crop associations as an alternative method to control aphids without insecticides in this region. [less ▲]

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See detailCrop association to improve aphid biological control
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Bodson, Bernard ULg et al

Poster (2014, August)

This research focused on the development of sustainable alternative methods to control aphids, giving special emphasis on cultural practices and plant management systems. Increasing the diversity within ... [more ▼]

This research focused on the development of sustainable alternative methods to control aphids, giving special emphasis on cultural practices and plant management systems. Increasing the diversity within crops may have several beneficial effects on pest control, creating attractive habitats for indigenous beneficial fauna and simultaneously deterring pests (“push-pull” approach). In this field study, two wheat/pea associations (mixed cropping and strip cropping) where compared to monocultures of pea and wheat. The abundance and diversity of adult aphidophagous beneficials (predators and parasitoids) were accessed weekly, using yellow traps, while aphids were observed directly on plants. All individuals were identified down to the level of species. In both crops, the percentage of aphid infestation and density of colonies were significantly higher in monocultures during the abundance periods. The mixing was particularly beneficial for the pea, while strip cropping was more efficient for the wheat. Concerning beneficials, their abundance was also significantly higher in monocultures, comparing with the other treatments. This study shows that increasing diversity within crops can prevent them from aphid infestations. However, additional methods are needed to attract more efficiently the aphidophagous beneficials, in order to promote the natural control of aphids. [less ▲]

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See detailEffects of wheat/oilseed rape and wheat/pea associations on the diversity of aphids and aphidophagous beneficials
Chevalier Mendes Lopes, Thomas ULg; Bosquée, Emilie ULg; Honba, David et al

Poster (2014, May 20)

This study was conducted in the Shandong province (China) to better characterize the effect of wheat/oilseed rape and wheat/pea associations on the populations of aphids and aphidophagous beneficials. At ... [more ▼]

This study was conducted in the Shandong province (China) to better characterize the effect of wheat/oilseed rape and wheat/pea associations on the populations of aphids and aphidophagous beneficials. At specific times of the season, the observations on wheat tillers confirm the resource concentration and the enemy hypotheses. In fact, aphids were more abundant in the pure stand of wheat, while more ladybirds were observed in the associations. As for the trapping of aphidophagous beneficials, the parasitoid species Aphidius gifuensis (Ashmead) was prevalent. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species. Few lacewings and hoverflies were trapped. This study shows a beneficial effect of crop associations on the control of aphid populations. [less ▲]

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