| 1. |
- Abdelfattah, Ahmed, et al.
(author)
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Metabarcoding: A powerful tool to investigate microbial communities and shape future plant protection strategies
- 2018
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In: Biological control (Print). - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1049-9644 .- 1090-2112. ; 120
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Journal article (peer-reviewed)abstract
- Microorganisms are the main drivers shaping the functioning and equilibrium of all ecosystems, contributing to nutrient cycling, primary production, litter decomposition, and multi-trophic interactions. Knowledge about the microbial assemblies in specific ecological niches is integral to understanding the assemblages interact and function the function, and becomes essential when the microbiota intersects with human activities, such as protecting crops against pests and diseases. Metabarcoding has proven to be a valuable tool and has been widely used for characterizing the microbial diversity of different environments and has been utilized in many research endeavors. Here we summarize the current status of metabarcoding technologies, the advantages and challenges in utilizing this technique, and how this pioneer approach is being applied to studying plant diseases and pests, with a focus on plant protection and biological control. Current and future developments in this technology will foster a more comprehensive understanding of microbial ecology, and the development of new, innovative pest control strategies.
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| 2. |
- Aebi, Alexandre, et al.
(author)
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The potential of native parasitoids for the control of Mexican bean beetles: A genetic and ecological approach
- 2008
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In: Biological Control. - : Elsevier BV. - 1090-2112 .- 1049-9644. ; 47:3, s. 289-297
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Journal article (peer-reviewed)abstract
- Bruchid beetles in the genus Zabrotes are important pests of field and stored beans all around the world and cause enormous economical losses in Mexico and Central America. Native parasitoids have been successfully used to suppress infestations by bruchid beetles in Africa, but few studies have assessed their potential to reduce seed damage in the New World and no successful biological control programs have been implemented, mainly due to the poor knowledge on their biology, systematics and ecology in this region. In this study, we used molecular tools to describe a new complex of three parasitoid species of bruchid beetles in the genus Horismenus, and investigated the level of gene flow and presence of ecotypes in this complex. We also examined the specific association between species of Horismenus and two sibling species of Zabrotes beetles, in order to evaluate their potential as biological control agents. Microsatellite data support the previous morphological description of three species, H. butcheri, H. missouriensis and H. depressus, but suggest some gene flow between H. missouriensis and H. depressus. Host-plant is shown to be the most important factor determining the ecological distribution of the two Zabrotes species, whereas altitude explains most of the distribution of the three Horismenus species. These results complement our understanding of this tritrophic system, providing a solid base for a potential biological control program using native parasitoids. (C) 2008 Elsevier Inc. All rights reserved.
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| 3. |
- Caballero-Lopez, B., et al.
(author)
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Aphids and their natural enemies are differently affected by habitat features at local and landscape scales
- 2012
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In: Biological Control. - : Elsevier BV. - 1090-2112 .- 1049-9644. ; 63:2, s. 222-229
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Journal article (peer-reviewed)abstract
- Biological control, an essential ecosystem service to agriculture, can be affected by ecological processes operating at landscape scales. Here we assessed the effect of landscape complexity, measured as proportion of arable land (PAL), on the abundance of aphids, parasitoids, and specialist and generalist predators. In addition we set up cage experiments to test the ability of these groups of enemies to suppress aphid densities. Landscape context did not significantly explain differences in aphid or parasitoid densities between fields. However, aphid densities were significantly higher in field interior compared to the margin. Coccinellid (specialist predator) abundance showed a similar pattern, with higher density in the field interior, indicating an aggregative response to aphid prey. In addition, Coccinellid abundance increased with PAL but only in field interiors and not at the field margins. The abundance of carabids (generalist predators) increased with PAL, suggesting that they benefit from landscape simplification. The cage experiment revealed that specialist as well as generalist predators were able to reduce the number of aphids on barley tillers and that a combination of both guilds did not provide a greater reduction of aphids. Our results suggest higher densities of generalist predators with increasing PAL Nonetheless, the greater abundance of coccinellids and carabid beetles in cereal fields embedded in simple landscapes does not necessarily imply better pest control since natural enemies may compete, thereby limiting their ability to control pests. (C) 2012 Elsevier Inc. All rights reserved.
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| 4. |
- Campolo, Orlando, et al.
(author)
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Interaction between ants and the Mediterranean fruit fly: New insights for biological control
- 2015
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In: Biological control (Print). - : ACADEMIC PRESS INC ELSEVIER SCIENCE. - 1049-9644 .- 1090-2112. ; 90, s. 120-127
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Journal article (peer-reviewed)abstract
- During recent years, the positive role of ants as biological control agents in agro-ecosystems has gained growing interest. We investigated the predatory relationship between Ceratitis capitata (Wiedemann) and the ant Tapinoma nigerrimum (Nylander), commonly widespread in the Mediterranean area. Additionally we investigated some bio-ethological aspects of C. capitata larvae that could be relevant timing factors for predation. Field observations highlighted that C. capitata larvae were preyed on by ants, and laboratory assays suggested that movement of medfly larvae, as well as olfactory cues, affected prey location by T. nigerrimum. Further observations on the circadian activity of C. capitata suggest that mature larvae leave the fruit to pupate in the soil mainly in the early morning, and they can bury faster in moistened soil. These ecological aspects are discussed in the context of sustainable agriculture. (C) 2015 Elsevier Inc. All rights reserved.
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| 5. |
- Dalin, Peter, et al.
(author)
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Global land-use change and the importance of zoophytophagous bugs in biological control: Coppicing willows as a timely example
- 2011
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 59, s. 6-12
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Journal article (peer-reviewed)abstract
- Perennial plants, such as willows, miscanthus, and hybrid poplars, are promising bioenergy crops while lowering atmospheric CO(2). Increases in the acreage of perennial bioenergy crops will pose new challenges and opportunities for biological control. In this review, we suggest that zoophytophagous bugs could be expected to become increasingly important in biological control of arthropod pests in perennial bioenergy crops. The main reasons are: (1) perennial bioenergy crops provide suitable habitats for arboreal natural enemies like zoophytophagous bugs; (2) zoophytophagous bugs often increase in response to low disturbance frequencies; and (3) plant-feeding by zoophytophagous bugs will not likely affect plant biomass production in perennial crops. We review aspects of the biology of zoophytophagous bugs expected to be important in biological control of pests in perennial systems. We also present a predator-prey model investigating how alternative harvest methods affect biological control of herbivorous pests by zoophytophagous bugs in willow biomass plantations. Although there is good evidence that zoophytophagous bugs can provide pest control, more research is needed about factors affecting the dispersal and population dynamics of zoophytophagous bugs in agricultural landscapes. (C) 2011 Elsevier Inc. All rights reserved.
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| 6. |
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| 7. |
- Johnsson, Anna-Ida, et al.
(author)
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Development and evaluation of SCAR markers for a Pseudomonas brassicacearum strain used in biological control of snow mould
- 2009
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 48, s. 181-187
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Journal article (peer-reviewed)abstract
- Biological control microorganisms have long been promoted as an alternative to conventional pesticides. Before registration of a microbial biocontrol product for commercial sale, it must be evaluated as regards potential spread and persistence after release. In this study, strainspecific sequence-characterized amplified region (SCAR) markers were developed to monitor the biocontrol candidate strain Pseudomonas brassicacearum MA250, which is effective against snow mould (Microdochium nivale). One SCAR marker, OPA2-73, was used in quantitative real-time PCR (Q-PCR) on samples from a climate chamber experiment in which winter wheat seeds were treated with the bacterium or a chemical control agent, or left untreated. The results showed that MA250 persisted for up to 3 weeks after sowing on the kernel residues and also colonized the roots of treated seedlings. Total MA250 cell numbers on biocontrol treated seedlings after three weeks were approximately 10(6) Cells, compared with the original inoculum of 10(6)-10(7) cells per seed. Corresponding cell numbers of MA250 on chemically treated and untreated seedlings were below the detection limit. This study shows that SCAR marker OPA2-73 is a specific and sensitive tool for monitoring the biocontrol microorganism MA250 in environmental samples. (C) 2008 Elsevier Inc. All rights reserved.
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| 8. |
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| 9. |
- Karlsson, Miriam Frida
(author)
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Interspecific competition between egg parasitoids: Native Fopius caudatus and exotic Fopius arisanus, in Ceratitis cosyra
- 2018
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 117, s. 172-181
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Journal article (peer-reviewed)abstract
- Tephritidae fruit flies are parasitized by Braconidae wasps, of which some are used in biological control programs. Releases of exotic parasitoids might affect, or be affected by, native species exploiting a common host. We studied interspecific competition between the native African parasitoid Fopius caudatus (Szepligeti) and the exotic Asian parasitoid Fopius arisanus (Sonan) (both Hymenoptera: Braconidae) in African native Ceratitis cosyra Walker (Diptera: Tephritidae). Wasp behaviour on infested fruits and dissection of fruit fly eggs assessed acceptance, oviposition performance and suitability for egg development, parasitism, and effect of parasitism by heterospecific species. While F. arisanus outcompeted F. caudatus in parasitization of relatively younger eggs, chased away F. caudatus, and oviposited more, F. caudatus survived better than F. arisanus. Fopius caudatus parasitized more in 2-day-old C. cosyra eggs than in 1 or 3-day-old egg. More oviposition by F. caudatus was found in fruits previously exposed to F. arisanus, coinciding with presence of more developed host eggs, while such difference was not observed for F. arisanus. Fopius caudatus was an inferior competitor than F. arisanus in C. cosyra-infested African mango Irvingia gabonensis (Irvingiaceae).
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| 10. |
- Kheam, Sokha, et al.
(author)
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The effects of cultivar mixtures on insect pest and natural enemy abundance, diseases, and yield in tropical soybean cropping system
- 2024
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In: Biological Control. - 1049-9644 .- 1090-2112. ; 196
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Journal article (peer-reviewed)abstract
- Increasing genotypic crop diversity via cultivar mixtures is a promising sustainable approach to control insect pests and diseases, thereby improving yield. The effects of genotypic diversity have not been studied for many crops. We investigated the effects of cultivar mixtures in a tropical soybean ( Glycine max L . Merrill) cropping system on i) insect pest abundance, ii) natural enemy abundance, iii) diseases, and iv) yield. In the field trial, three soybean cultivars were used, two commercial and one traditional, with a randomized complete block design. Significant differences among cultivars and some mixtures were found for certain insect pest abundance (whitefly and brown bean bug), but no consistent mixture effects were observed. Significant increases in natural enemies (predatory ant, lady beetle, parasitoid wasp, and dragonfly) were detected in some cultivar mixtures, compared to single cultivars. Higher genetic diversity in cultivar mixtures increased the abundance of certain natural enemies at specific plant stages. The cultivar mixtures did not alter disease symptoms or yield. These results were obtained during a season with very low overall pest pressure, and the effects of cultivar mixtures might be altered at higher pest pressure, which should be further investigated. This study highlights trade-offs in cultivar selection when jointly considering pest and disease abundance and yield, as no single cultivar (or mixture) performed better in all observed aspects. Our study supports the hypothesis that increasing cultivar mixtures can promote the abundance of certain natural enemies, suggesting the potential of cultivar mixture effects for biological control and sustainable agricultural management.
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| 11. |
- Kuusk, Anna-Karin, et al.
(author)
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Lycosid spiders and alternative food: Feeding behavior and implications for biological control
- 2010
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 55, s. 20-26
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Journal article (peer-reviewed)abstract
- The extent to which generalist arthropod predators feed on natural populations of alternative prey, and how availability of such food influences biological control of agricultural pests, is largely unknown. A major reason is that direct estimation of arthropod predation in food webs is a methodological challenge. Here, we report the first use of DNA-technology to track predation by lycosid spiders on natural populations of springtails. Predators were collected in cereals and leys on organic farms in central Sweden. In parallel, the availability of springtails and other potential alternative prey was monitored. The collected spiders (n = 469) were analyzed using group-specific springtail PCR-primers. Spiders collected in cereals had previously been screened for consumption of an aphid pest, and by combining those data with availability of alternative prey, we tested if presence of alternative food affected aphid predation. In total, 20% of Pardosa were found to have preyed upon springtails. The proportion of spiders consuming springtails did not differ between habitats; 19% positive in leys and 22% in cereals. Springtail consumption was not correlated with springtail abundance. Our results demonstrate that springtails are an important source of alternative food for Pardosa. Thus, presence of springtails may contribute to spider population maintenance and, indirectly, to enhanced predation pressure on co-occurring pests. However, we also found evidence that high abundances of alternative prey may interfere with aphid predation. We suggest that changes in the spiders' foraging behavior, rather than increased springtail consumption, is the underlying mechanism. (C) 2010 Elsevier Inc. All rights reserved.
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| 12. |
- Mgbeahuruike, Anthony Christian, et al.
(author)
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Screening of Phlebiopsis gigantea isolates for traits associated with biocontrol of the conifer pathogen Heterobasidion annosum
- 2011
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 57, s. 118-129
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Journal article (peer-reviewed)abstract
- Stump treatment with Phlebiopsis gigantea has been widely used as the preferred method for the control of the conifer pathogen, Heterobasidion annosum sensu lato. However, the traits underlying this biocontrol process are not fully known. Sixty-four heterokaryotic isolates of P. gigantea from diverse geographical sources were screened for growth rate, laccase production, wood decay capability and antagonistic ability under in vitro conditions. In parallel, spore production, antagonism and growth rates were tested on a subset of 17 homokaryotic isolates and were compared with the heterokaryon strains of the same isolates. The data were statistically analysed using multiple regression and principal component analysis. The result showed that 90% of the P. gigantea isolates were able to replace H. annosum on wood medium compared to 4% on glucose-rich medium. The growth rate on modified nutrient medium supplemented with sawdust showed positive interrelationship with growth rate on the medium with xylan (P = 0.0001), % weight loss in pine (P = 0.02) and interaction in xylan (P = 0.08); but was negatively interrelated with growth rate on nutrient medium containing ferulic acid (P = 0.03). Antagonism on sawdust was positively interrelated with laccase production (P = 0.03) and % weight loss in pine (P = 0.05) but negatively dependent on growth rate in xylan (P = 0.03). There was a significant variation in spore production between the homokaryons and the heterokaryons of the same strains. The results show that the antagonistic interaction is partly dependent on the ability of the two fungi to degrade the different structural components of wood. Crown Copyright (C) 2011 Published by Elsevier Inc. All rights reserved.
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| 13. |
- Moritz, Kim, et al.
(author)
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Plant sex effects on insect herbivores and biological control in a Short Rotation Coppice willow
- 2017
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In: Biological control (Print). - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 115, s. 30-36
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Journal article (peer-reviewed)abstract
- In the wild, plant sex can affect plant-herbivore interactions and higher trophic levels, including natural enemies of the herbivores. However, the possibility of manipulating plant sex to improve biological control and reduce herbivory in domesticated dioecious crops remains unexplored. The dioecious bioenergy crop, Salix viminalis, is often planted in monoclonal, and thus monosexual, fields. We investigated whether using plant clones of either sex, or mixing plants of both sexes, reduced the performance and abundance of the herbivorous pest insect Phratora vulgatissima and its main natural enemy, Anthocoris nemorum, and whether predation was affected. The herbivore laid more eggs, and the predator survived longer, on female plants in the lab. However, these effects did not translate into differences in predation rates in laboratory experiments or differential insect abundances on plants of either sex or plantation sex composition in the field. Plant genotype did have a significant effect on insect abundances, but this was due to plant traits other than sex. The results indicate that manipulating plant sex will not lead to improved biological control or reduced insect herbivory in S. viminalis energy forestry, but suggest that a focus on plant genotypic differences offers promise for improving management practices.
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| 14. |
- Muoni, Tarirai
(author)
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Friends or foes? Population dynamics of beneficial and detrimental aerial arthropods under Conservation Agriculture
- 2020
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 148
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Journal article (peer-reviewed)abstract
- Arthropod pest control is one of the most critical agronomic practices in cereal-based cropping systems. Cropping systems that preserve or promote biological pest control agents are more desirable. Data collected from a long-term trial at the Monze Farmer Training Centre (MFTC) from 2009 to 2012 was used to compare effects of different Conservation Agriculture (CA) systems with conventional practices (CP) on arthropod species diversity and populations with specific emphasis on beneficial and detrimental aerial arthropods. Up to 13 arthropod orders comprising of 40 species were identified in the cropping systems and their population density differed in years and cropping systems. Higher diversity was observed in CA systems in all years based on the Shannon-Weiner indices ranging from 0.4 to 2. However, a CP system with no rotations (CP-M) showed comparable results in the year with low rainfall. Community evenness increased in the same year with a value of 0.46. More beneficial and detrimental arthropods were recorded in a CA system with a three-year rotation of maize, cotton and sunnhemp reaching up to 9533 individuals ha(-1). The CP-M recorded the highest increase in detrimental arthropods from 2009 to 2012. A canonical correspondence analysis did not show a clear-cut association of both CA and CP systems with either beneficial or detrimental arthropods. However, associations were more driven by seasonal effects. Reduced soil disturbance, crop residue retention and crop diversity in CA systems preferentially attracted beneficial arthropods while preserving existing favourable arthropods. Conventional tillage systems often disturbed arthropod habitats, disrupted their life cycles leading to lower biological activity. Increased biodiversSity from CA systems may therefore support biological control.
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| 15. |
- Musaqaf, Nimra, et al.
(author)
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Effects of strawberry resistance and genotypic diversity on aphids and their natural enemies
- 2022
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 170
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Journal article (peer-reviewed)abstract
- Ecological theory hypothesizes that plant trait diversity may be as important as the presence of specific functional traits (e.g., resistance) for the herbivore and predator communities within a population. We used experimental populations of wild woodland strawberry (Fragaria vesca) to test whether the degree of plant genotypic diversity and/or the existence of specific resistance traits play a role in the host plant’s community structure specifically, the community of generalist and specialist aphids and their natural enemies. In 2019, we studied the aphid abundance and relative predator abundance in an experimental field site in Alnarp, Southern Sweden; the field consisted of plots planted with combinations of 20 different wild strawberry genotypes. These strawberry genotypes were previously identified as either susceptible to or resistant against the herbivorous beetle (Galerucella tenella). Two aphid species, Chaetosiphon fragaefolii (specialist) and the exotic Aphis gossypii (generalist) were found in the plots and of the two species A. gossypii was dominant. The abundance of the specialist aphid (C. fragaefolii) was highest in susceptible plots with high genotypic diversity, while the generalist (A. gossypii) was highest in plots with a mix of resistant and susceptible plants with high genotypic diversity. Anthocorid predators, developed significantly higher population densities in strawberry plots with high genotypic diversity. Overall, predator abundance showed a positive correlation with aphid abundance. These results show that the specific functional trait of resistance as well as plant diversity affected aphids. Knowledge about these effects can be important factors to consider when designing strawberry plantings less susceptible to aphids.
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| 16. |
- Ninkovic, Velemir, et al.
(author)
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Ladybird footprints induce aphid avoidance behavior
- 2013
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 65, s. 63-71
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Journal article (peer-reviewed)abstract
- Predation has immediate consequences for prey fitness and early assessment of predation risk may be advantageous for prey. We investigated the ability of the bird cherry-oat aphid, Rhopalosiphum padi (L.), to detect one of its important predators, seven spot ladybird, Coccinella septempunctata L., via chemicals in the predator's walking track. Ladybird tracks left on leaves elicited avoidance and reduced host plant settling in aphids via contact and olfactory cues or a combination of both. Aphid avoidance behavior was dependent on ladybird sex and number of individuals, with the odor of a single ladybird eliciting attraction and the odor of several ladybirds causing avoidance. This suggests that aphids may be able to assess the risk of predation via the extent of the chemical tracks and adjust their behavioral response accordingly. Aphid responses to ladybird tracks decreased with the age of the track, potentially preventing aphids from avoiding plants on which predators have not been recently active. This avoidance mechanism may play an important role in the biological control exerted by predatory ladybirds on aphid populations. (C) 2012 Elsevier Inc. All rights reserved.
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| 17. |
- Rivas-Franco, Frederico, et al.
(author)
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Effects of a maize root pest and fungal pathogen on entomopathogenic fungal rhizosphere colonization, endophytism and induction of plant hormones
- 2020
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In: Biological control (Print). - : Academic Press Inc.. - 1049-9644 .- 1090-2112. ; 150
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Journal article (peer-reviewed)abstract
- Some entomopathogenic fungi, such as Metarhizium spp. and Beauveria spp., closely interact with plants by colonizing the rhizosphere or growing endophytically inside root tissues. These characteristics increase the potential for endophytic entomopathogenic fungi to persist in the root system when used as biological control agents. The mechanism by which endophytic entomopathogenic fungi are capable to colonize the internal plant tissues is also influenced by plants and can be regarded as an adaptive protection acquired by plants against herbivorous insects. The mutual benefits obtained by plants and fungi through this peculiar endophytic association supports the bodyguard hypothesis. The objectives of this study were to evaluate the ability of different isolates of Metarhizium spp. and a single isolate of Beauveria bassiana, coated onto seeds, to colonize the rhizosphere and root tissues of maize (Zea mays) and to assess whether the presence of an insect pest and fungal root pathogen influenced this interaction. All the entomopathogenic fungal isolates tested were able to colonize the rhizosphere to some extent, but one isolate of M. anisopliae and the one of M. robertsii performed best. Overall, the presence of Costelytra giveni (Scarabaeidae) larvae significantly decreased rhizosphere colonization by the entomopathogens, while the phytopathogenic fungus Fusarium graminearum (Nectriaceae: Hypocreales) did not. Similarly, the presence of C. giveni decreased endophytic growth in root tissues by around 75% when considering all entomopathogens together. In contrast, a 112% increase in overall root endophytic colonization occurred in the presence of F. graminearum. Salicylic acid (SA) and jasmonic acid (JA) content in maize plants changed depending on the isolate of M. anisopliae incorporated through seed coating and root herbivory by larval presence. In the absence of C. giveni, plants treated with M. anisopliae A1080 had higher SA and JA root content than control plants. Conversely, when larvae were present, maize plants treated with M. anisopliae F672 had increased levels of both phytohormones, indicating a potentially primed state. The observed decrease in root colonization by some entomopathogenic fungal isolates in the presence of larvae of C. giveni and the increase in endophytic colonization in the presence of F. graminearum are in accordance with the bodyguard hypothesis. Additionally, the changes observed in the SA and JA content in Metarhizium treated plants corresponded to plant responses related to systemic acquired resistance and to induced systemic resistance. Our results demonstrate that biotic soil factors can shape the outcome of endophytic entomopathogenic fungi-plant interaction, as well as affecting the plant physiology.
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| 18. |
- Stenberg, Johan A
(author)
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Plant-mediated effects of different Salix species on the performance of the braconid parasitoid Perilitus brevicollis
- 2012
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 60, s. 54-58
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Journal article (peer-reviewed)abstract
- The blue willow beetle, Phratora vulgatissima, is considered to be the most damaging herbivorous pest in Salix short-rotation coppices throughout Europe. The braconid parasitoid Perilitus brevicollis is an important natural enemy of Phratora. As several different Salix species are used in coppices, I investigated the bottom-up (tritrophic) effects of Salix on the parasitoid. Three host plants were studied: the introduced fast-growing S. viminalis, which is highly susceptible to the beetle; S. dasyclados, which is introduced and moderately-resistant to the beetle; and the native slow-growing Salix cinerea, which is not currently used in coppices. The identity of the host-plant species had significant effects on parasitoid larval development time; parasitoids developed rapidly on the susceptible S. viminalis and slowly on the moderately resistant S. dasyclados. Increased development time resulted in reduced adult longevity. Host-plant species identity also affected larval survival; 57%, 64%, and 49% of the parasitoids successfully completed larval development in beetles fed S. viminalis, S. cinerea, and S. dasyclados, respectively. Parasitoid development was also correlated with the body size of their beetle host, but this effect was independent of the identity of the host-plant species. The results of this study suggest that the parasitoid has higher survival and growth rates when it parasitizes beetles feeding on the common coppice species S. viminalis, but the performance of the parasite is reduced when the beetle feeds on the moderately-resistant S. dasyclados. Conversely, the omnivorous biocontrol agents sometimes used in these systems appear to perform better on S. dasyclados compared to S. viminalis. The results of this study suggest that Perilitus parasitoids and omnivorous beetle predators may provide complementary protection to Salix and therefore be useful in coppice management. (C) 2011 Elsevier Inc. All rights reserved.
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| 19. |
- Stenlid, Jan, et al.
(author)
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Natural infection and colonization of pre-commercially cut stumps of Picea abies and Pinus sylvestris by Heterobasidion rot and its biocontrol fungus Phlebiopsis gigantea
- 2020
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 143
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Journal article (peer-reviewed)abstract
- Fungi from the genus Heterobasidion are among the most important pathogens of forest trees in Northern Hemisphere causing root rot and wood decay, while Phlebiopsis gigantea is a very common saprotrophic wood decay fungus. Both fungi are primary colonizers of freshly cut conifer stumps (through which Heterobasidion spp. accomplishes primary infections of tree root systems), thus both fungi are competing for the substrate. To date, P. gigantea is widely used as Heterobasidion spp. biocontrol agent. Hypothesis has been proposed that natural colonization of stumps by P. gigantea might also to some extent restrict infections by the pathogen. The main aim of the study was to assess the potential of natural infections of P. gigantea to restrict infection and spread of Heterobasidion spp. in Picea abies and Pinus sylvestris stumps. In total, 793 P. abies stumps and 1158 P. sylvestris stumps were examined in 24 sample plots located in the eastern part of Latvia. Of these, 325 (41.0%) P. abies stumps were infected by Heterobasidion spp., and 59 (7.4%) by P. gigantea, and 168 (14.5%) P. sylvestris stumps were infected by Heterobasidion spp., and 846 (73.1%) by P. gigantea. In P. abies, the observed Heterobasidion spp. infection frequencies were significantly (p < 0.05) higher than those of P. gigantea, while the respective situation in P. sylvestris was reverse and P. gigantea infections were more frequent (p < 0.05). The mean surface area colonized by Heterobasidion spp. in P. abies and P. sylvestris stumps was 5.7 and 5.3 cm(2) and did not differ significantly (mean coverage of stump surface area respectively 18% and 13%; p = 0.41). In contrast, the mean surface area colonized by P. gigantea was significantly different in the two tree species, respectively, 3.9 and 21.3 cm(2) (16% and 59%; p < 0.05). The mean surface area colonized by Heterobasidion spp. in P. abies stumps was significantly larger (p < 0.05) than the area colonized by P. gigantea, while conversely, the mean area colonized by P. gigantea in P. sylvestris stumps was significantly larger (p < 0.001) than that colonized by Heterobasidion spp. Both fungi were co-occurring in P. abies stumps in 33 cases (4.2% of all investigated stumps), and in P. sylvestris stumps in 138 cases (11.9%). There were no correlations between the sizes of colonized areas of Heterobasidion spp. and P. gigantea in P. abies stumps (r = 0.06; p = 0.76), or P. sylvestris stumps (r = 0.009; p = 0.27). In conclusion, the results of this study strongly suggest that even in stumps of P. sylvestris, that otherwise are much preferred for natural colonization by airborne spores of the biocontrol agent P. gigantea, natural colonization by P. gigantea is not able to restrict infections by Heterobasidion spp. This clearly indicates that for effective biocontrol of Heterobasidion spp. infections, the necessity for thorough treatment coverage of cut P. abies and P. sylvestris stumps at early stages of plantation management, during pre-commercial thinning.
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| 20. |
- Sundh, Ingvar
(author)
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Sense and nonsense of the secondary metabolites data requirements in the EU for beneficial microbial control agents
- 2019
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In: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 136
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Journal article (peer-reviewed)abstract
- Microbial control agents (MCAs) are promising for use in sustainable agriculture. Nevertheless, they face a major hurdle in the registration process of the European Union, one reason being unclear data requirements on metabolites. This review examines the EU regulatory perspective on metabolites of MCAs for plant protection and identifies some key issues and concerns. Current data requirements for secondary metabolites of micro-organisms are based on degradation products/metabolites of chemicals. We conclude that this has contributed strongly to the current confusion regarding how to best evaluate potential production of toxic substances by MCAs. We suggest that data requirements should be revised and/or need guidance fit for purpose, in order to give the EU-regulation for MCAs a stronger base in microbiological knowledge. We also suggest implementation of a basic hazard assessment. If this is passed without any concerns, the production of unknown, potentially toxic, substances does not need to be further investigated.
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| 21. |
- Alexandridis, Nikolaos, et al.
(author)
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Models of natural pest control : Towards predictions across agricultural landscapes
- 2021
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In: Biological Control. - : Elsevier BV. - 1049-9644. ; 163
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Research review (peer-reviewed)abstract
- Natural control of invertebrate crop pests has the potential to complement or replace conventional insecticide-based practices, but its mainstream application is hampered by predictive unreliability across agroecosystems. Inconsistent responses of natural pest control to changes in landscape characteristics have been attributed to ecological complexity and system-specific conditions. Here, we review agroecological models and their potential to provide predictions of natural pest control across agricultural landscapes. Existing models have used a multitude of techniques to represent specific crop-pest-enemy systems at various spatiotemporal scales, but less wealthy regions of the world are underrepresented. A realistic representation of natural pest control across systems appears to be hindered by a practical trade-off between generality and realism. Nonetheless, observations of context-sensitive, trait-mediated responses of natural pest control to land-use gradients indicate the potential of ecological models that explicitly represent the underlying mechanisms. We conclude that modelling natural pest control across agroecosystems should exploit existing mechanistic techniques towards a framework of contextually bound generalizations. Observed similarities in causal relationships can inform the functional grouping of diverse agroecosystems worldwide and the development of the respective models based on general, but context-sensitive, ecological mechanisms. The combined use of qualitative and quantitative techniques should allow the flexible integration of empirical evidence and ecological theory for robust predictions of natural pest control across a wide range of agroecological contexts and levels of knowledge availability. We highlight challenges and promising directions towards developing such a general modelling framework.
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| 22. |
- Favaro, Riccardo, et al.
(author)
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Host instar influence on offspring sex ratio and female preference of Neodryinus typhlocybae (Ashmead) (Hymenoptera, Dryinidae) parasitoid of Metcalfa pruinosa (Say) (Homoptera, Flatidae)
- 2018
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In: Biological Control. - : Elsevier BV. - 1049-9644. ; 125, s. 113-120
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Journal article (peer-reviewed)abstract
- The parasitoid wasp Neodryinus typhlocybae (Ashmead) was introduced to Europe for the biological control of nearctic planthopper Metcalfa pruinosa (Say), which causes severe damage to both crops and ornamental species in the absence of specialized natural enemies. We performed a series of experiments to evaluate the host instar preference and the effects on parasitoid offspring sex. Results showed that parasitism occurs mostly on 3rd, 4th and 5th host instars. Male parasitoid offspring were reared exclusively from 3rd instars. Both male and female offspring originated from the 4th instar, but the sex ratio remained male-biased. A greater proportion of female offspring originated from the 5th instar. Virgin mothers produced exclusively male progeny. When female wasps were exposed to an equal proportion of 3rd, 4th and 5th host instars, parasitism occurred predominantly on the 5th instar, while the least parasitized was the 3rd instar. The age of female wasps did not influence the preference for host instars or the offspring sex ratio. However, females previous experienced with small host instars resulted in a greater production of female offspring on the 5th instar, compared to females which had never encountered small instars. We discuss the relevance of these findings, which could provide new insights for the optimization of the mass rearing of this parasitoid wasp.
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| 23. |
- Jarrett, Benjamin J.M., et al.
(author)
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Experimental adaptation of native parasitoids to the invasive insect pest, Drosophila suzukii
- 2022
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In: Biological Control. - : Elsevier BV. - 1049-9644. ; 167
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Journal article (peer-reviewed)abstract
- The spread of invasive pests is increasing due to greater global transportation and climate change-mediated range shifts. In a new community, these invasive species provide a novel resource that native predators or parasitoids can evolve to utilise. For invasive agricultural pests, this could provide top-down control; however, initial attack rates on invasive species in the wild are generally low. The potential for rapid adaptive evolution of native species to improve developmental success on invasive species is unknown. We address this by focusing on Drosophila suzukii, a polyphagous invasive pest, and two cosmopolitan Drosophila parasitoids found in North America prior to the arrival of D. suzukii (Pachycrepoideus vindemiae and Trichopria drosophilae). We experimentally evolved three replicate populations of both species on D. suzukii and the cosmopolitan D. melanogaster, a common host for both parasitoids. We found evidence that P. vindemiae increased developmental success by 88% (95% credible intervals = [−14%, 254%]) and T. drosophilae increased developmental success by 259% [38%, 711%] on D. suzukii after only three generations of selection, despite very low founding sizes of 2 and 30 wasps, respectively. These results demonstrate that rapid evolution of increased virulence is possible even from low genetic diversity, with implications for integrating evolutionary techniques into biological control of invasive species.
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| 24. |
- Linder, Shelley, et al.
(author)
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Non-target attack of the native stink bug, Podisus maculiventris by Trissolcus japonicus, comes with fitness costs and trade-offs
- 2023
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In: Biological Control. - : Elsevier BV. - 1049-9644. ; 177
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Journal article (peer-reviewed)abstract
- Accidentally introduced parasitoids can provide biological control of the invasive pest they followed but could also pose a threat to native species if they are not specialists. Attack of native species could reduce the effectiveness of adventive natural enemies if it is accompanied by reduced fitness, and it may increase acceptance of non-target species. We tested how intermittent host shift and prolonged exposure to a non-target, native species Podisus maculiventris (Say) (Hemiptera: Pentatomidae) may affect the fitness and host acceptance of the egg parasitoid, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) that was co-introduced with the invasive Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). In the first experiment, replicate parasitoid populations were reared either with or without a history of host switching over a 10-generation period between the native and the invasive stink bug that was followed by three generations of continuous reproduction on either host. In the second experiment, replicated populations were exposed for three continuous generations to either the native or invasive host. Occasional or prolonged reproduction on the native host did not increase acceptance and developmental success on the non-target species. Emergence rate of T. japonicus was consistently lower when it reproduced on the native stink bug. There was also a trade-off for the parasitoid, in terms of reduced emergence rate, when switching back to H. halys from the native host. These results suggest that host shifts to native species could reduce the effectiveness of T. japonicus at attacking H. halys, but the fitness costs may prevent significant non-target effects in nature.
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| 25. |
- Rosero, Pedro, et al.
(author)
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Impacts of landscape heterogeneity on bottom-up effects affecting biological control
- 2024
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In: Biological Control. - 1049-9644. ; 188
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Journal article (peer-reviewed)abstract
- Conservation biological control of crop pests by natural enemies relies on management strategies to favour their trophic interactions. In agricultural landscapes, natural enemies acting across habitat boundaries may feed on non-pest prey, resulting in apparent competition between non-pest prey and pests. Such communities, including pests, non-pest prey, and natural enemies have been shown to be affected by landscape heterogeneity depending on the dispersal capacity of the interacting organisms. Nonetheless, a mechanistic understanding of how natural enemies’ dispersal capacity interacts with landscape heterogeneity affecting conservation biological control is, however, lacking. Here, we contribute to such mechanistic understanding through modelling. We simulated the consequences of differences in landscape heterogeneity defined by the contrast of plant resource distribution in a semi-natural habitat compared to a crop and variation in natural enemy dispersal capacity on biological control of a pest. Our model showed that variation in plant resource distribution resulted in bottom-up effects that led to shifts in the dominant mechanism underlying biological control. At high landscape heterogeneity when resources differ strongly between crop and the semi-natural habitat, non-pest prey benefitted from the plant resources available, promoting apparent-competition-mediated biocontrol for high-dispersing natural enemies. At low landscape heterogeneity, pests benefitted mostly from plant resources available, promoting direct plant-pest-enemy mediated biocontrol. Interestingly, intermediate levels of landscape heterogeneity resulted in the lowest levels of biocontrol. Our results highlight the importance of potential bottom-up effects that the matching between plant resources available in a habitat and the resource preference of herbivores can induce on conservation biological control.
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| 26. |
- Vasiliauskas, R., et al.
(author)
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Persistence and long-term impact of Rotstop biological control agent on mycodiversity in Picea abies stumps
- 2005
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In: Biological Control. - : Elsevier BV. - 1049-9644. ; 32:2, s. 295-304
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Journal article (peer-reviewed)abstract
- To prevent infection by the root rot fungi Heterobasidion spp., surfaces of freshly cut Picea abies stumps are sprayed with Rotstop biocontrol agent, which constitutes a spore suspension of a single genotype of the competitive fungus Phlebiopsis gigantea. In Fennoscandia, the agent is applied on 47,000 ha of forestland yearly. The aims of the present work were to estimate the persistence of Rotstop P. gigantea strain and its impact on mycodiversity in 4- to 6-year-old P. abies stumps. Fungal isolation was done from 947 wood samples taken from 130 stumps, 60 of which were Rotstop-treated and 70 were untreated controls. Half of the stumps were 4-year, and another half 6-year-old. 705 fungal strains representing 81 species were isolated. Species richness was lower in Rotstop-treated stumps, both after 4 (by 32%; P = 0.08) and after 6 years (46%; P = 0.01). The majority of species (6575%) isolated from Rotstop-treated stumps were also found in controls. In 4-year-old Rotstop-treated stumps, the fungal community was dominated by P. gigantea, both in terms of isolated strains and observed fruitbodies. Of P. gigantea isolates, only Rotstop genotypes were found in treated stumps, while control stumps harboured wild strains of the species. In 6-year-old both treated and control stumps, P. gigantea was seldom detected and no fruitbodies were observed. Here, the occurrence of other fungi increased, e.g., Resinicium bicolor, Sistotrema brinkmannii, and Hypholoma capnoides. The pathogen, Heterobasidion spp., was the only basidiomycete with a significantly reduced incidence in Rotstop-treated stumps
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| 27. |
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