Lene Sigsgaard
Senior Research Scientist
Abstract
Simple Summary: One of the main insect pests in protected strawberry production are thrips, but little is known about which species of thrips are present in the production system. In this study, we identified the thrips species of adults and larvae present in two strawberry cultivars at a commercial strawberry farm in Denmark. The most abundant species found were Frankliniella intonsa, followed by Thrips tabaci. The abundance of thrips peaked in July (temperature range 18–23 ◦C, mean humidity 65%, mean precipitation 5 mm). More thrips were found in the earlier flowering cultivar. In order to optimize control of thrips, a fundamental first step is knowing which species are present on the target crop. Abstract: Thrips are a major pest in protected strawberry production. Knowledge of thrips species composition could be instrumental for improved thrips management, but very little is known about which species are present in strawberries grown in high-tunnels in Denmark. Thrips (adults and larvae) were sampled in two strawberry tunnels of the cultivars Murano and Furore from May to August 2018, in the middle and in the edges of the tunnels. The most abundant thrips species found in the tunnels were Frankliniella intonsa and Thrips tabaci adults. Frankliniella intonsa were also the most frequently found species of the immatures sampled, followed by T. tabaci larvae, and other species. The number of thrips differed between the two cultivars, sampling times and location in the tunnel. Frankliniella intonsa was more abundant in the middle of the tunnels, while T. tabaci was more abundant in the edge of the tunnels adjacent to the field margins. The number of thrips peaked by the end of July. Both chemical and biological control should consider species composition and occurrence; hence, a fundamental first step for thrips management is to identify the species present on the target crop.
Authors
Raimondas Mozūraitis David Hall Nina Trandem Baiba Ralle Kalle Tunström Lene Sigsgaard Catherine Baroffio Michelle Fountain Jerry Cross Atle Wibe Anna-Karin Borg-KarlsonAbstract
The strawberry blossom weevil (SBW), Anthonomus rubi, is a major pest in strawberry fields throughout Europe. Traps baited with aggregation pheromone are used for pest monitoring. However, a more effective lure is needed. For a number of pests, it has been shown that the attractiveness of a pheromone can be enhanced by host plant volatiles. The goal of this study was to explore floral volatile blends of different strawberry species (Fragaria x ananassa and Fragaria vesca) to identify compounds that might be used to improve the attractiveness of existing lures for SBW. Floral emissions of F. x a. varieties Sonata, Beltran, Korona, and of F. vesca, were collected by both solid-phase microextraction (SPME) and dynamic headspace sampling on Tenax. Analysis by gas chromatography/mass spectrometry showed the floral volatiles of F. x ananassa. and F. vesca were dominated by aromatic compounds and terpenoids, with 4-methoxybenzaldehyde (p-anisaldehyde) and α-muurolene the major compounds produced by the two species, respectively. Multi-dimensional scaling analyses separated the blends of the two species and explained differences between F. vesca genotypes and, to some degree, variation between F. x ananassa varieties In two-choice behavioral tests, SBW preferred odors of flowering strawberry plants to those of non-flowering plants, but weevils did not discriminate between odors from F. x ananassa and F. vesca flowering plants. Adding blends of six synthetic flower volatiles to non-flowering plants of both species increased the preference of SBW for these over the plants alone. When added individually to non-flowering plants, none of the components increased the preference of SBW, indicating a synergistic effect. However, SBW responded to 1,4-dimethoxybenzene, a major component of volatiles from F. viridis, previously found to synergize the attractiveness of the SBW aggregation pheromone in field studies.
Abstract
We determined how conidia of arthropod-pathogenic fungi on leaves affected the behavior of two predators—Orius majusculus (Hemiptera: Anthocoridae) and Phytoseiulus persimilis (Acari: Phytoseiidae)—when offered a choice between preying on two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), in the presence or absence of infective conidia of Metarhizium brunneum (Ascomycota: Hypocreales) and Neozygites floridana (Entomophthoromycota: Neozygitaceae). The results indicate no significant relation between the presence of conidia and predator behavior. The only indication of interference is between the generalists O. majusculus and M. brunneum, with a trend towards more time spent feeding and more prey encounters turning into feeding events on leaf discs without conidia than on leaf discs with conidia. Our results show that the presence of fungal conidia does not alter the preying behavior of the predators, and using predators and fungi together is not limited by any interference between organisms in the short term.
Authors
Michelle T. Fountain Catherine Baroffio Anna-Karin Borg-Karlson Phil Brain Jerry V. Cross Dudley I. Farman David R. Hall Baiba Ralle Paolo Rendina Pauline Richoz Lene Sigsgaard Sverre Storberget Nina Trandem Atle WibeAbstract
Strawberry blossom weevil (SBW), Anthonomus rubi Herbst (Coleoptera: Curculionidae) and European tarnished plant bug (ETB), Lygus rugulipennis Poppius (Hetereoptera: Miridae), cause significant damage to strawberry and raspberry crops. Using the SBW aggregation pheromone and ETB sex pheromone we optimized and tested a single trap for both species. A series of field experiments in crops and seminatural habitats in five European countries tested capture of the target pests and the ability to avoid captures of beneficial arthropods. A Unitrap containing a trapping agent of water and detergent and with a cross vane was more efficient at capturing both species compared to traps which incorporated glue as a trapping agent. Adding a green cross vane deterred attraction of non-pest species such as bees, but did not compromise catches of the target pests. The trap caught higher numbers of ETB and SBW if deployed at ground level and although a cross vane was not important for catches of ETB it was needed for significant captures of SBW. The potential for mass trapping SBWand ETB simultaneously in soft fruit crops is discussed including potential improvements to make this more effective and economic to deploy.
Authors
Bjørn Arild Hatteland Elena Therese Wulf-Vester Ida Gundersen Nuria Agusti Lene Sigsgaard Nina TrandemAbstract
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Authors
Atle Wibe Anna-Karin Borg-Karlson Jerry Cross Helena Bichao Michelle Fountain Ilme Liblikas Lene SigsgaardAbstract
The aggregation pheromone of strawberry blossom weevil[Anthonomus rubi Herbst (Col.: Curculionidae)],a 1:4:1 blend of Grandlure I, II and racemic lavadulol, has been available for pest monitoring for several years but shows low attractancy. Attempts to control A. rubi using the pheromone alone were also unsuccessful. This paper reports the finding that addition of the major flower volatile from Wild strawberry flowers [Fragaria vesca L. (Rosaceae)], 1,4-dimethoxybenzene (comprising 98% of the volatiles emitted from wild strawberry flowers), to the aggregation pheromone increased trap catches by over two fold compared to the pheromone alone. There was no significant difference between the response of overwintered or summer emerged adults. Field trials in 2007e2008 in central and southern Norway, Denmark and southern England used green funnel traps with white cross vanes for the evaluations. (-)-Germacrene D, previously shown to be emitted by plants in increased amounts in the presence of pheromone producing weevils, did not improve trap catches. Thus, the combined use of the aggregation pheromone and 1,4-dimethoxybenzene is promising for improved monitoring and possibly control of this important pest of strawberry.
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Authors
Atle Wibe Jerry Cross Anna-Karin Borg-Karlson David Richard Hall Nina Trandem Lene Sigsgaard Catherine A Baroffio Baiba Ralle Michelle FountainAbstract
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Lene Sigsgaard Cyril Naulin Solveig Haukeland Kristian Kristensen Annie Enkegaard Nauja Lisa Jensen Jørgen EilenbergAbstract
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Jørgen Eilenberg Anette Jensen Celeste P. D'Alessandro Lene Sigsgaard Silvia Helena Galvâo de Miranda Jens Erik Ørum Ingeborg Klingen I. Jr. DelaliberaAbstract
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Atle Wibe Ilze Apenite Catherine A Baroffio Anna-Karin Borg-Karlson Jerry Cross David Richard Hall Lene Sigsgaard Nina TrandemAbstract
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Atle Wibe Ilze Apenite Catherine A Baroffio Anna-Karin Borg-Karlson Jerry Cross David Richard Hall Lene Sigsgaard Nina TrandemAbstract
No abstract has been registered
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