Diplodia sapinea, an important pathogen of various conifer species, was recently recorded in the ... more Diplodia sapinea, an important pathogen of various conifer species, was recently recorded in the northern Baltic region. The pathogen can disperse over short distances via rain or wind, whereas long range dispersal occurs via movement of contaminated plant material and seeds by humans, as well as by insects. Hylobius abietis is one of the most important forest pests over large areas of Europe. Adult weevils feed on the bark of seedlings of young conifers, causing injury and often death. Weevils were collected from fresh clear‐cut areas and near the symptomatic conifer stands to analyze the presence of D. sapinea. Entire weevils collected from natural environments were crushed without surface washing. The identity of D. sapinea and the fungal DNA extraction from the insects was confirmed by species‐specific polymerase chain reaction priming. Eight H. abietis individuals were determined to be infected with D. sapinea. In a laboratory experiment, pine branches were infected with D. sapinea and were fed to adult H. abietis. The results show that the pathogen survived in the digestive tract of H. abietis in the laboratory experiment, and also that the isolation of fungus from the faeces was successful. In addition, the results demonstrate that the large pine weevil may be a potential vector of pathogenic fungus D. sapinea.
Predacious carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) is a fast-moving ins... more Predacious carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) is a fast-moving insect which should be considered as an important component of biological control in organic farming. In this study we tested some factors of potentially dangerous influence of pesticide Fastac (synthetic pyrethroid) on overwintering physiology of adult ground beetle under laboratory conditions. Cold-hardiness (measured by supercooling point SCP) was determined 2 weeks after exposure to pesticide treated-food. Pesticide had decreased cold- hardiness of the ground beetles. Weak supercooling capacity could be harmful to overwintering insects in cold winters without snow cover.
The metabolic rate and respiratory patterns of adults of the large pine weevil, Hylobius abietis ... more The metabolic rate and respiratory patterns of adults of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae) was compared in hydrated and dehydrated conditions using a constant volume electrolytic respirometer-actograph combined with an infrared actograph. The weevils displayed continuous pumping movements in hydrated conditions (hydrated individuals) while the cyclic gas exchange was entirely lacking or only unclear small releases of CO2 (bursts, B) were observed. However, when a short period of quiescent state (tonic immobility) was artificially induced by a mechanical stimulus, 3-6 clear cycles of gas exchange appeared, with the frequency of 14-18 cycles per hour, i.e. the discontinuous gas exchange cycles or DGCs were displayed. These were recognized as CFO (closed, flutter, open) type of gas exchange cycles known by closed-flutter-open phases of spiracular movements without active ventilation, i.e. pumping movements, during the bursts. At 0oC, when the musc...
The oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) wa... more The oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) was investigated on white cabbage cultivars under field conditions in two vegetation periods. Significantly less eggs were laid on cultivar 'Golden Acre'. There were no differences in the number of eggs found on the cultivar 'Lennox', 'Krautman', 'Krautkaiser' and 'Turquoise'. The cultivar 'Parel' showed different results during experimental period. The data on cabbage moth oviposition preferences can be used in sustainable plant protection strategies in organic farming.
Diplodia sapinea, an important pathogen of various conifer species, was recently recorded in the ... more Diplodia sapinea, an important pathogen of various conifer species, was recently recorded in the northern Baltic region. The pathogen can disperse over short distances via rain or wind, whereas long range dispersal occurs via movement of contaminated plant material and seeds by humans, as well as by insects. Hylobius abietis is one of the most important forest pests over large areas of Europe. Adult weevils feed on the bark of seedlings of young conifers, causing injury and often death. Weevils were collected from fresh clear‐cut areas and near the symptomatic conifer stands to analyze the presence of D. sapinea. Entire weevils collected from natural environments were crushed without surface washing. The identity of D. sapinea and the fungal DNA extraction from the insects was confirmed by species‐specific polymerase chain reaction priming. Eight H. abietis individuals were determined to be infected with D. sapinea. In a laboratory experiment, pine branches were infected with D. sapinea and were fed to adult H. abietis. The results show that the pathogen survived in the digestive tract of H. abietis in the laboratory experiment, and also that the isolation of fungus from the faeces was successful. In addition, the results demonstrate that the large pine weevil may be a potential vector of pathogenic fungus D. sapinea.
Predacious carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) is a fast-moving ins... more Predacious carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) is a fast-moving insect which should be considered as an important component of biological control in organic farming. In this study we tested some factors of potentially dangerous influence of pesticide Fastac (synthetic pyrethroid) on overwintering physiology of adult ground beetle under laboratory conditions. Cold-hardiness (measured by supercooling point SCP) was determined 2 weeks after exposure to pesticide treated-food. Pesticide had decreased cold- hardiness of the ground beetles. Weak supercooling capacity could be harmful to overwintering insects in cold winters without snow cover.
The metabolic rate and respiratory patterns of adults of the large pine weevil, Hylobius abietis ... more The metabolic rate and respiratory patterns of adults of the large pine weevil, Hylobius abietis (L.) (Coleoptera: Curculionidae) was compared in hydrated and dehydrated conditions using a constant volume electrolytic respirometer-actograph combined with an infrared actograph. The weevils displayed continuous pumping movements in hydrated conditions (hydrated individuals) while the cyclic gas exchange was entirely lacking or only unclear small releases of CO2 (bursts, B) were observed. However, when a short period of quiescent state (tonic immobility) was artificially induced by a mechanical stimulus, 3-6 clear cycles of gas exchange appeared, with the frequency of 14-18 cycles per hour, i.e. the discontinuous gas exchange cycles or DGCs were displayed. These were recognized as CFO (closed, flutter, open) type of gas exchange cycles known by closed-flutter-open phases of spiracular movements without active ventilation, i.e. pumping movements, during the bursts. At 0oC, when the musc...
The oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) wa... more The oviposition preference of the cabbage moth, Mamestra brassicae L. (Lepidoptera: Noctuidae) was investigated on white cabbage cultivars under field conditions in two vegetation periods. Significantly less eggs were laid on cultivar 'Golden Acre'. There were no differences in the number of eggs found on the cultivar 'Lennox', 'Krautman', 'Krautkaiser' and 'Turquoise'. The cultivar 'Parel' showed different results during experimental period. The data on cabbage moth oviposition preferences can be used in sustainable plant protection strategies in organic farming.
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