Residual activity of insecticides applied against Lobesia botrana and its influence on resistance management strategies.

Some insect growth disruptors, in particular chitin synthesis inhibitors (benzoylphenyl ureas) and ecdysone agonists (bisacylhydrazines), show high efficacy against Lobesia botrana (Denis et Schiffermuller) (Lepidoptera Tortricidae) and are characterized by a longer residual activity than the traditional organophosphate active ingredients. Previous research had shown that the persistence of some active ingredients applied against the first generation of L. botrana also ensured control of the second generation. In this study, the residual activity of insecticides applied against the second generation was evaluated on the third generation in field trials and laboratory bioassays. Methoxyfenozide controlled the third generation at the same efficacy level (more than 90%) when applied against the second or the third generations. Some residual activity was observed in the field also for indoxacarb (efficacy 75%). In contrast, a very low residual activity (efficacy lower than 30%) was recorded for chlorpyrifos. Because a longer residual activity is associated with a higher risk of selecting insecticide resistant populations, operational resistance management strategies are discussed to ensure a longer usable life span of these insecticides

Neodryinus typhlocybae (Ashmead) antagonista di Metcalfa pruinosa (Say). Risultati di liberazioni pluriennali effettuate in Friuli-Venezia Giulia

Neodryinus Typhlocybae (ASHMEAD) AS A BIOLOGICAL CONTROL AGENT OF metcalfa pruinoSa (SAY). RESULTS OF PLURENNIAL RELEASES CARRIED OUT IN FRIULI-VENEZIA GIULIA During the three-year period 1998-2000 the entomophagous wasp Neodryinus typhlocybae (Ashmead) (Hymenoptera Dryinidae) was released to control the planthopper Metcalfa pruinosa (Say) (Homoptera Flatidae). The releases were carried out in 88 sites of 42 localities in the Friuli- Venezia Giulia region (north-eastern Italy). Between the end of May and the beginning of June, 200 N. typhlocybae cocoons, containing pupae, were placed in each site (woods, hedgerows, parklands). The entomophagous wasp became established in 83 cases out of 88 (94%) as shown by the numerous cocoons, containing overwintering larvae, found on the leaf undersurface of various trees and bushes at the end of the year. A few years after the introduction, populations of N. typhlocybae could still be found around release sites, showing that this species can permanently colonise different environments. In the first year, cocoons of the wasp were usually found up to 20-30 m from the original point of release. In successive years they were observed even at a distance of several kilometres from the release point, indicating that the adults can cover relatively long distances. Neodryinus typhlocybae will very probably colonise all the areas in the region that are infested by M. pruinosa, resulting in a significant reduction in the quantity of insecticides needed to control this pest. Key words: Biological control, Planthopper, Dryinid wasp, release.Nel triennio 1998-2000 sono state effettuate in Friuli-Venezia Giulia immissioni dell’entomofago Neodryinus typhlocybae (Ashmead) (Hymenoptera Dryinidae) contro Metcalfa pruinosa (Say) (Homoptera Flatidae). I rilasci sono stati condotti in 88 siti di lancio di 42 località della regione; in ogni sito (es. boschetti, siepi interpoderali, aree a parco) sono stati collocati, a fine maggio-inizi di giugno, 200 bozzoli di N. typhlocybae contenenti pupe pronte allo sfarfallamento. Le immissioni hanno avuto successo in 83 casi su 88 (94%), in quanto a fine anno è stato possibile rinvenire sulla pagina inferiore di varie piante arboree o arbustive numerosi bozzoli contenenti larve svernanti dell’entomofago. Numerosi campionamenti, anche a distanza di vari anni dal rilascio, hanno permesso di accertare che le popolazioni di N. typhlocybae permangono in loco, dimostrando così la capacità dell’entomofago di colonizzare permanentemente vari ambienti. I bozzoli dell’imenottero nel corso del primo anno sono stati rinvenuti di norma fino a 20-30 m dal punto di rilascio; negli anni successivi essi sono stati rilevati anche a diversi chilometri dal punto di lancio, dimostrando la capacità degli adulti dell’entomofago di percorrere distanze tutt’altro che trascurabili (anche dell’ordine di 1 km all’anno). È prevedibile che N. typhlocybae possa colonizzare nel territorio regionale tutte le zone infestate da M. pruinosa, consentendo una significativa riduzione degli interventi insetticidi contro il fitofago. Parole chiave: Lotta biologica, Flatidi, Driinidi, liberazioni.

Rinvenimento della cimice esotica Halyomorpha halys (St\ue5l) a Portogruaro (VE)

Finding of the brown marmorated stink bug Halyomorpha halys in Portogruaro (Venice district). In November 2015, an overwintering specimen of the brown marmorated stink bug Halyomorpha halys (St\ue5l) (Heteroptera, Pentatomidae) was found in a house located in the periurban area of Portogruaro (Venice district). It seems to be the first discovery of this alien and invasive species in the district of Venice