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Pathogenic soft rot Enterobacteriaceae (SRE) belonging to the genera Pectobacterium and Dickeya cause diseases in potato and numerous other crops. Seed potatoes are the most important source of infection, but how pathogen-free tubers initially become infected remains an enigma. Since the 1920s, insects have been hypothesized to contribute to SRE transmission. To validate this hypothesis and to map the insect species potentially involved in SRE dispersal, we have analyzed the occurrence of SRE in insects recovered from potato fields over a period of 2 years. Twenty-eight yellow sticky traps were set up in 10 potato fields throughout Norway to attract and trap insects. Total DNA recovered from over 2,000 randomly chosen trapped insects was tested for SRE, using a specific quantitative PCR (qPCR) TaqMan assay, and insects that tested positive were identified by DNA barcoding. Although the occurrence of SRE-carrying insects varied, they were found in all the tested fields. While Delia species were dominant among the insects that carried the largest amount of SRE, more than 80 other SRE-carrying insect species were identified, and they had different levels of abundance. Additionally, the occurrence of SRE in three laboratory-reared insect species was analyzed, and this suggested that SRE are natural members of some insect microbiomes, with herbivorous Delia floralis carrying more SRE than the cabbage moth (Plutella xylostella) and carnivorous green lacewing larvae (Chrysoperla carnea). In summary, the high proportion, variety, and ubiquity of insects that carried SRE show the need to address this source of the pathogens to reduce the initial infection of seed material.

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1. Push-pull or stimulo-deterrent cropping systems combine a trap crop or other attractant or arrestant stimulus distant from the crop and a deterrent or repellent near or within the target crop, to divert pests, reducing their populations on the target crop. Although the concept is decades old, there are few successful applications in pest management. 2. In this article, we address this shortcoming by offering a mechanistic conceptual framework of push-pull systems, based on the cues, sensory modalities, pest behaviours and spatial ranges over which they can occur during host selection and that can influence pest distribution. 3. We review published work on push-pull systems in the light of this framework, finding that the literature tends to focus on longer-range stimulo-deterrence strategies rather than the full range of cues involved and modalities that can come into play, with imperfect understanding of cues involved in most systems. 4. The imbalance in research emphasis and incomplete understanding of push-pull mechanisms suggest opportunities to improve and broaden the palette of potential push-pull technologies. 5. The framework also helps clarify other aspects important for achieving success with push-pull methods, including the role of synergy, deployment geometry, intraspecific variability and the wider arthropod community in these systems. 6. Synthesis and applications. A conceptual and mechanistic framework is provided for the development of push-pull or stimulo-deterrent pest management approaches. This framework informs a proposed research agenda for designing push-pull technologies. That agenda involves including all cues and modalities, exploiting synergies, tuning deployment geometry in accordance with these factors. It also considers pest and crop dynamics and the arthropod community of the system. The framework can benefit managers by helping them to consider more fully the behaviour of the target pests when creating crop and non-crop geometries to achieve push-pull benefits. Research-based push-pull systems will be better implemented and modified by producers if they understand how insects respond to sources of push and pull in the system, allowing effective monitoring and fine-tuning to increase effectiveness of this specialized component of integrated pest management.

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The effect of different degrees of attack by carrot psyllid (Trioza apicalis) on quality parameters of carrots was studied in field experiments for two years. Treatments were different degrees of physical insect protection by floating row cover. An increasing attack level of psyllids showed an enhancement effect on the antioxidant capacity (ORAC), content of falcarindiol, 6-methoxymellein, and terpenes, and scores for bitter taste, chemical flavor, terpene flavor, and toughness. Carrot psyllid attack decreased the yield, total sugar, fructose, glucose, and sensory attributes sweet taste, color hue, color strength, crispiness, and juiciness. Carrot plants at 8−10 weeks of age tolerated attack by psyllids at low levels (2% leaves with curling or discoloration).

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Resistens eller nedsatt følsomhet mot kjemiske skadedyrmidler er funnet hos flere skadedyrarter i bl.a. oljevekster, jordbær, potet og prydplanter i veksthus. Dette fører til bekjempelsesproblemer, økt sprøyting og risiko for resistens mot nye midler.

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Fra 1. januar 2008 er ingen effektive skadedyrmidler godkjent for bruk mot kålfluer i Norge. Det har siden 2004 vært en stor innsats ved Bioforsk i samarbeid med Landbrukets forsøksringer og med næringen til å finne frem til metoder og midler som vil beskytte korsblomstrede vekster mot kålfluer. Det er spesielt to prosjekter som har støttet mye av dette arbeid, ett brukerstyrt fra kålrotdyrkerne og ett fra Forskningsfondet. Resultatene viser at både nye midler og andre bekjempelsesmetoder kan gi tilfredsstillende beskyttelse. Men det er mye arbeid som gjenstår før all den nye viten kan tas i bruk.