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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2023

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Abstract

The Expert Group for Technical Advice on Organic Production (EGTOP) was requested to advise on the use of several substances with plant protection effects in organic production. The Group discussed whether the use of these substances and methods is in line with the objectives and principles of organic production, and whether they should be included in Reg. (EU) 2021/1165. With respect to Annex I to Reg. (EU) 2021/1165, the Group recommends the following: • Entry ‘Pheromones and other semiochemicals’: The present restriction ‘only in traps and dispensers’ should be complemented with the following text: ‘microcapsules shall be biodegradable and shall not be applied to edible parts of the crop’. • The introductions to Annex I and to the sub-chapters of Annex I refer to the authorization of pesticides pursuant to Regulation (EC) No 1107/2009. The Group recommends minor editorial amendments to clarify that these references apply only when pesticides are used within the EU.

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Abstract

The Expert Group for Technical Advice on Organic Production (EGTOP) was requested to advise on the use of several substances with plant protection or fertilising effects in organic production, and to advise on aspects of organic production of yams. The Group discussed whether the use of these substances and methods is in line with the objectives and principles of organic production, and whether they should be included in Reg. (EU) 2021/1165. With

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Abstract

Key words: apiculture, biological control, Norwegian Environment Agency, Norwegian Scientific Committee for Food and Environment, predatory mites, risk assessment, varroa Introduction The Norwegian Environment Agency (NEA) have asked the Norwegian Scientific Committee for Food and Environment for an assessment of adverse impacts on biodiversity concerning import and release of the predatory mite Stratiolaelaps scimitus as measure against varroa mites (Varroa destructor) in apiaries. The predatory mite is already in use in Norwegian greenhouses and polytunnels as a biological control agent against dark-winged fungus gnats in a various of plant cultures. The NEA has received an application for a new type of use: to combat varroa mites in apiaries. Background Varroa destructor (the varroa mite) is a species of parasitic mite that feeds externally on honeybees; it is considered one of the major threats to beekeeping world-wide due to its parasitic behaviour and because it acts as a vector for several viral and bacterial bee pathogens. Beekeepers in North America have begun experimenting with introducing Stratiolaelaps scimitus, a commercially available predaceous mite originally used for biocontrol in greenhouses and polytunnels, to control varroa mites, and several studies on the use of the mite in this context have been published recently. The Norwegian Environment Agency has asked VKM to assess the risk to biological diversity in Norway associated with this new use of S. scimitus, and to assess the effects of climate change on any risks that are proposed. Stratiolaelaps scimitus is a tiny (0.5 mm), soil-dwelling predaceous mite that in nature feeds on a wide variety of soil invertebrates, including fly larvae, nematodes, nymphs of thrips, potworms (oligochaetes), springtails, and other mites. For over three decades, Stratiolaelaps scimitus has been produced commercially and the species is now used globally for biological control. The mite is applied to control a wide variety of organisms harmful to food production or to the production of ornamental plants, but especially to combat infestations of fungus gnat larvae, spider mites, flower thrips, and certain plant-feeding nematodes. The species is already used as a biocontrol agent in Norway in greenhouses, open plastic polytunnels used for protecting crops, and in various indoor plantings and fungiculture. Methods VKM established a project group with expertise in entomology, invasion ecology, honeybee behaviour and ecology, and risk analysis of biological control agents. The group conducted systematic literature searches and scrutinized the relevant literature that was found. In the absence of Norwegian studies, VKM relied on literature from other countries. Results and conclusions This VKM assessment concludes with medium confidence that introducing S. scimitus for use in beehives would not significantly increase the probability of establishment and spread of S. scimitus above that of its current use. We point out that there is no evidence that continuous use of S. scimitus in Norway, over decades, has led to its establishment outside of enclosures, including open polytunnels. The optimal temperature for development and reproduction is far higher than what is normally observed in Norway (~28 °C). Although lethal temperature has been reported to be as low as –5.2 °C, we still conclude that S. scimitus would not be able to establish permanent populations in Norway, not even in the southern part of the country as such temperatures are expected to occur in some years throughout the country. Future climate change is not believed to alter this conclusion, since periods with lethally cold temperatures are expected to still occur in the future.

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Abstract

Pandora neoaphidis is a common entomopathogenic fungus on Sitobion avenae, which is an important aphid pest on cereals in Europe. Pandora neoaphidis is known to cause epizootics (i.e. an unusually high prevalence of infected hosts) and the rapid collapse of aphid populations. We developed a weather-driven mechanistic model of the winter wheat-S. avenae-P. neoaphidis system to simulate the dynamics from spring to harvest. Aphid immigration was fixed at a rate that would lead to a pest outbreak, if not controlled by the fungus. We estimated the biocontrol efficacy by running pair-wise simulations, one with and one without the fungus. Uncertainty in model parameters and variation in weather was included, resulting in a range of simulation outcomes, and a global sensitivity analysis was performed. We identified two key understudied parameters that require more extensive experimental data collection to better assess the fungus biocontrol, namely the fungus transmission efficiency and the decay of cadaver, which defines the time window for possible disease transmission. The parameters with the largest influence on the improvement in yield were the weather, the lethal time of exposed aphids, the fungus transmission efficiency, and the humidity threshold for fungus development, while the fungus inoculum in the chosen range (between 10 and 70% of immigrant aphids carrying the fungus) was less influential. The model suggests that epizootics occurring early, around Zadoks growth stage (GS) 61, would lead to successful biocontrol, while later epizootics (GS 73) were a necessary but insufficient condition for success. These model predictions were based on the prevalence of cadavers only, not of exposed (i.e. infected but yet non-symptomatic) aphids, which in practice would be costly to monitor. The model suggests that practical Integrated Pest Management could thus benefit from including the cadavers prevalence in a monitoring program. We argue for further research to experimentally estimate these cadaver thresholds.

To document

Abstract

Pandora neoaphidis is a common entomopathogenic fungus on Sitobion avenae, which is an important aphid pest on cereals in Europe. Pandora neoaphidis is known to cause epizootics (i.e. an unusually high prevalence of infected hosts) and the rapid collapse of aphid populations. We developed a weather-driven mechanistic model of the winter wheat-S. avenae-P. neoaphidis system to simulate the dynamics from spring to harvest. Aphid immigration was fixed at a rate that would lead to a pest outbreak, if not controlled by the fungus. We estimated the biocontrol efficacy by running pair-wise simulations, one with and one without the fungus. Uncertainty in model parameters and variation in weather was included, resulting in a range of simulation outcomes, and a global sensitivity analysis was performed. We identified two key understudied parameters that require more extensive experimental data collection to better assess the fungus biocontrol, namely the fungus transmission efficiency and the decay of cadaver, which defines the time window for possible disease transmission. The parameters with the largest influence on the improvement in yield were the weather, the lethal time of exposed aphids, the fungus transmission efficiency, and the humidity threshold for fungus development, while the fungus inoculum in the chosen range (between 10 and 70% of immigrant aphids carrying the fungus) was less influential. The model suggests that epizootics occurring early, around Zadoks growth stage (GS) 61, would lead to successful biocontrol, while later epizootics (GS 73) were a necessary but insufficient condition for success. These model predictions were based on the prevalence of cadavers only, not of exposed (i.e. infected but yet non-symptomatic) aphids, which in practice would be costly to monitor. The model suggests that practical Integrated Pest Management could thus benefit from including the cadavers prevalence in a monitoring program. We argue for further research to experimentally estimate these cadaver thresholds.