[Monitoring the resistance of Cydia pomonella to insecticides in Emilia-Romagna region: laboratory tests and field trials [Malus pumila Mill.]]
2006
Butturini, A. | Caroli, I. | Boselli, M. | Fagioli, L.
English. Diapausing larvae of Cydia pomonella from 13 heavily infested orchards of Emilia-Romagna were tested for resistance by topical application of discriminating concentrations. Wild moths showed a significant lower susceptibility to organophosphates (12 populations out of 13 analysed), insect growth regulators (8 out of 13), but also to thiacloprid (4 out of 9) and spinosad (6 out of 8) than a laboratory susceptible colony. The efficacy of insecticides against the first generation of the pest was checked with two field trials. Practical resistance to diflubenzuron and methoxyfenozide (-6 and 11% efficacy, respectively) was observed in one orchard and to chlorpyrifos (0% efficacy) in the second one. Flufenoxuron, azinphos-methyl, thiacloprid and spinosad were always highly effective. Laboratory response to IGRs consisted with field efficacy in the case both of the resistant and of the susceptible population. On the other hand, laboratory response to OPs was very low in both populations, regardless of the field susceptibility. These results may limit the validity of topical tests on diapausing larvae for monitoring resistance to organophosphates
Show more [+] Less [-]Italian. La sensibilità di Cydia pomonella agli insetticidi è stata valutata con biosaggi su larve diapausanti raccolte in 13 frutteti fortemente infestati. In laboratorio, fosforganici e regolatori della crescita (RCI) hanno mostrato una sensibile riduzione di efficacia. Prove di campo in due frutteti di origine delle larve hanno confermato la presenza di resistenza pratica a diflubenzuron, methoxyfenozide e chlorpyrifos. La validità dei biosaggi come strumento idoneo al monitoraggio della resistenza pratica ai RCI è evidenziata dalla buona correlazione tra risultati di laboratorio e di campo. La correlazione per thiacloprid e spinosad è promettente, ma dovrà essere validata anche su popolazioni resistenti. I biosaggi con chlorpyrifos e azinphos-methyl non possono invece ritenersi indicativi di resistenza pratica, poiché i risultati ottenuti non appaiono correlati con i dati di efficacia in campo
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