Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2019
Forfattere
Wiktoria Kaczmarek-Derda Anne-Kari Holm Lars Olav Brandsæter Knut Asbjørn Solhaug Inger Sundheim FløistadSammendrag
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Sammendrag
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Sammendrag
We studied the effect of three Pandora neoaphidis isolates from one Sitobion avenae population, three temperatures, and two aphid species namely S. avenae and Rhopalosiphum padi on (i) aphid mortality, (ii) time needed to kill aphids, and (iii) aphid average daily and lifetime fecundity. A total of 38% of S. avenae and 7% of R. padi died and supported fungus sporulation. S. avenae was killed 30% faster than R. padi. Average daily fecundity was negatively affected only in S. avenae inoculated with, but not killed by, P. neoaphidis. Nevertheless, lifetime fecundity of both aphid species inoculated and sporulating with P. neoaphidis was halved compared to lifetime fecundity of surviving aphids in the control. Increased temperature resulted in higher mortality rates but did not consistently affect lethal time or fecundity. Results suggest that (i) temperature effects on virulence differ between isolates, even when obtained within the same host population, and (ii) even though an isolate does not kill a host it may reduce its fecundity. Our findings are important for the understanding of P. neoaphidis epizootiology and for use in pest-natural enemy modelling.
Sammendrag
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Sammendrag
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Sammendrag
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Sammendrag
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Sammendrag
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Sammendrag
Although supporting high productivity, modern agriculture caused a long-term impact on natural trophic interactions, releasing pests from pressure linked with their natural enemies. Studies have demonstrated that volatiles released under herbivory can recruit natural enemies of pests from a distance. Here, we used a novel biodegradable formulation loaded with induced and food-signalling volatiles with the aim to attract the green lacewing, Chrysoperla carnea, and increase biological control of two cereal aphids Sitobion avenae and Rhopalosiphum padi. The new product consisted of a biodegradable matrix loaded with a 3-component blend of methyl salicylate, acetic acid and phenylacetaldehyde in a 1:1:1 ratio. Field experiments were carried out in a barley field in Norway. Single plants were provided with a 1 ml dollop of the new formulation or with a standard polyethylene emballage dispenser loaded with the same amount of compounds. The number of lacewing eggs and larvae as well as the attraction of additional natural enemies was recorded both on the treated and surrounding plants by visual inspection. At the same time, an assessment of aphid infestation was carried out. A higher local density of lacewing adults, eggs and larvae over an 8-week period was observed for both the standard and the biodegradable formulation in comparison with untreated plants. Chemical analysis of the volatiles emitted from the slow-release matrix showed an active emission of the blend over at least a 4-week period. Significant biological control of aphid was measured in the vegetation surrounding the odour source. Both aphid populations were significantly reduced, with no difference between the new and the standard treatment. While coccinellids and hoverflies were not affected by the treatment, a lower number of mummified aphids were measured in some of the treated plants in comparison with untreated ones. Results show the potential for semiochemical-based targeted attraction of lacewings to enhance biological control of aphids in a prevalent monoculture field setting. Additional studies are required to support the development of practical integrated pest management guidelines, including optimization of application density, threshold value for pest and natural enemies and practical recommendation for the establishment of non-crop vegetation within and around the crop.
Forfattere
Gunda ThömingSammendrag
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