490 research outputs found

    Dead Leaf Clusters as Habitats for Adult \u3ci\u3eCalliodis Temnostethoides\u3c/i\u3e and \u3ci\u3eCardiastethus Luridellus\u3c/i\u3e and Other Anthocorids (Hemiptera: Heteroptera: Anthocoridae)

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    Two species of Anthocoridae (Hemiptera: Heteroptera) were found in dead-leaf clusters of black oak in west-central Michigan, Calliodis temnostethoides and Cardiastethus luridellus. These clusters resulted from full- leafed trees being blown over by a severe wind storm in May 1998. They contained spiders, springtails, tubiliferan thrips, small beetles, and psocids, besides the predaceous anthocorids. Such habitats are well-known for some bugs elsewhere. Because only adults were collected, it was assumed that the more permanent habitat was likely to be under bark. Further attention to this habitat likely will result in additional records for other species of Anthocoridae

    Anthocorid bugs (Hemiptera, Anthocoridae) as natural predators of apple aphids and pear psyllids using spatial and temporal scales

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    Farmers in Norway are facing challenges like reduced access to pesticides, climate change and problems associated with increased homogeneity of crops in farming. Biological control may provide a solution to these challenges, by increasing the biodiversity and robustness in the surrounding ecosystems. The anthocorid bugs Anthocoris nemorum and A. nemoralis are considered to be effective predators on three important pest species in Norwegian fruit production: the pear psyllid Cacopsylla pyri in pear, and the green apple aphid Aphis pomi and the rosy apple aphid Dysaphis plantaginea in apple. The aim of this study was to investigate the potential of A. nemorum and A. nemoralis as biological control agents of these pest species in Norway. Field surveys and semi-field experiments were carried out in apple and pear orchards in western Norway. The predation potential was tested by performing sleeve-cage experiments. Information about spatial and temporal patterns of natural populations of A. nemorum and A. nemoralis and their prey was obtained by sampling orchards and analyzing the data with generalized linear mixed models (GLMM) incorporating the spatial structure. The results from the sleeve cage experiments showed that A. nemorum has the potential to control both C. pyri populations in pear and aphid populations in apple. Surprisingly, commercially bought A. nemoralis did not manage to reduce C. pyri populations, when compared to the control. Differences between commercially reared and natural populations of A. nemoralis should be researched. Results from the orchard survey in pear supported the hypothesis that natural populations of A. nemoralis are more specialized towards finding C. pyri nymphs and eggs than A. nemorum. However, A. nemorum was present in the orchard earlier, and in larger abundances than other studies has suggested. This highlights that A. nemorum’s role in controlling pear psyllids may be more important in Norway than previously assumed. The presence of ants was negatively related to number of Anthocorid nymphs in pear, and to imago A. nemorum in apple. Ants should therefore be taken into account when biocontrol systems in orchards are planned.Norske bønder står foran utfordringer som redusert tilgang på kjemiske plantevernmidler, klimaendringer og problemer som oppstår når homogenitet i avlinger øker i jordbruket. Disse utfordringene kan møtes ved bruk av biologisk kontroll, fordi økt biodiversitet i jordbruksområder gjør habitatet mer robust mot endringer. Nebbtegene Anthocoris nemorum og A. nemoralis er ansett å være effektive predatorer på tre viktige skadedyr i eple og pære i Norge: Vanlig pæresuger Cacopsylla pyri er skadedyr i pære. Grønn eplebladlus Aphis pomi og rød eplebladlus Dysaphis plantaginea er skadedyr i eple. Målet med dette studiet var å undersøke om A. nemorum og A. nemoralis har potensiale som nyttedyr for biologisk kontroll i eple- og pærefelt. Informasjon om A. nemorum og A. nemoralis ble samlet inn gjennom feltundersøkelser og kontrollerte feltforsøk. Predasjonspotensialet til nebbtegene ble undersøkt gjennom et nettposeforsøk. For å analysere hvordan nebbtegene beveger seg i tid og rom i pære- eller eplefeltet ble en generell lineær blandet modell (GLMM) brukt. Feltundersøkelsene og felteksperimentene ble utført i både eple og pære. Nettposeforsøket viste at A. nemorum kan kontrollere populasjoner av C. pyri i pære, og populasjoner av A. pomi i eple. A. nemoralis påvirket ikke antallet C. pyri i nettposeforsøket, noe som var overraskende. Forskjeller mellom naturlige norske populasjoner og kommersielt oppfostrede A. nemoralis kunne med fordel undersøkes mer. I feltundersøkelsen støttes hypotesen at A. nemoralis er mer spesialisert og bedre til å finne C. pyri enn A. nemorum i pære. A. nemorum var likevel også viktig, fordi det var flere individer av den i pærefeltet, noe som ikke var forventet. I eple har A. nemorum potensialet til å kontrollere populasjoner av eplebladlus hvis antallet nebbteger øker. Det var et negativ forhold mellom maur og anthocoris nymfer i pære og imago A. nemorum i eple. De kan derfor være en viktig faktor i skadedyrkontroll, og burde tas hensyn til når bruken av biologisk kontroll planlegges i eple- og pærefelt.M-ECO

    A simulation model for the functional response of Orius sauteri on eggplant leaves with Thrips palmi: Implications for biological control.

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    The predation capability of the anthocorid predatory bug Orius sauteri (Poppius) determines its effectiveness for suppressing Thrips palmi Karny on greenhouse eggplants. For quantifying the daily impact of one predator on its prey, we use its patch leaving behaviour on eggplant leaves with different prey numbers and scale up to the larger spatiotemporal scale of the greenhouse and one foraging day, using literature data on the distribution of T. palmi over eggplant leaves. The simulation result is a type-II functional response of O. sauteri as function of average T. palmi density: around the economic injury level of T. palmi, i.e., 0.55 individuals per leaf, O. sauteri can find and eat approximately 10 prey per day. The sensitivity analysis showed that the baseline leaving tendency, the presence of and the encounter rate with prey have a relatively large effect on the daily mean number of prey eaten per O. sauteri predator, i.e., its predation capability

    Hyperpredators of the pear psylla, Psylla pyricola Foerster (Homoptera: Chermidae)

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