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Remarks on the biology of Dinera ferina (Diptera Tachinidae) as parasitoid of the two Italian Platycerus species (Coleoptera Lucanidae)
Full text linkRecords of asilidae and muscidae (Diptera) as predators of Platycerus caraboides and Platycerus caprea (Coleoptera Lucanidae) larvae in deadwood in northern Italy
No full textThe present paper reports cases of predation on two Italian species of stag beetles, Platycerus caprea and Platycerus caraboides, by saproxylic Diptera of which preys were seldom reported or unknown in the literature. Resulting from eight years of collections in many sites in northern Italy, the robber flies Laphria meridionalis and Choerades sp. eclosed in rearing boxes of P. caraboides, and the muscid fly Phaonia palpata emerged from deadwood inhabited by both Platycerus species. These Diptera developed in deadwood of broadleaves species, where they were uncommon predators of Platycerus immature stages. Predator-prey interactions between Asilidae and Muscidae larvae and Platycerus improve the knowledge on the community of these species with hidden habits in the saproxylic scene
Seasonal population dynamics, thermal tolerance, and damage assessment of the invasive pest Brown Marmorated Stink Bug, Halyomorpha halys
Full text linkThe brown marmorated stink bug, Halyomorpha halys, is an invasive pest species native from East Asia and introduced into the USA, Europe, and South America. This pest can feed on more than 170 plant species among orchards, vegetables, row crops, and ornamentals, and it causes damage on crops and nuisance to the human population due to its overwintering behavior. In the present work we studied the invasion pattern of the pest, its impact on grapevine and the effect of abiotic (low and high temperatures) and biotic (natural enemies) factors that can influence the population dynamics. The genetic structure of H. halys and of its primary symbiont, ‘Candidatus Pantoea carbekii’, were studied to elucidate the pathways of expansion of the pest across the invaded area. Some populations from north-eastern Italy showed the highest values of genetic diversity, and possible multiple introductions from different countries are suggested considering the affinity with symbiont haplotypes. Seasonal dynamics of H. halys in multi-cultivar vineyards and the damage on grape clusters were also studied, showing a higher H. halys abundance on red-berry cultivars than on white ones, on varieties ripening late in the season and on the border of the vineyards. Halyomorpha halys infestations caused damage on berries, showing a different cultivar and plant phenological stages susceptibility, and that damage was relevant only with high infestations, not commonly found in vineyards. Botrytis cinerea occurrence was correlated to H. halys presence, and this represents the main issue related to H. halys effect on the grapevine and should be considered in the definition of integrated pest management strategies on this crop. From the studies on lethal temperature exposures, exiting diapause adults were more sensitive to low- and high-temperature exposures than entering ones, and insects with a low nutritional status showed higher mortality levels after low-temperature exposures. Following low-temperature exposures, an increase in longevity and a reduction of fecundity of entering diapause H. halys females were also detected. The results showed that low temperatures in winter and spring can have an impact on the survival rate and population development of H. halys. Moreover, the mortality-curves obtained from high-temperature exposures can be used for the definition of cost-effective heat treatments aimed at the H. halys control. Finally, H. halys egg parasitoids complex was also studied, and the presence of Trissolcus mitsukurii, a species previously found in Asia, was recorded. This parasitoid shows a high impact on host eggs. By studying the genetic variability of the parasitoid population, the relation between Italian samples and Japanese and Chinese ones was detected. The study performed on the egg parasitoid complex of H. halys in northern Italy provides promising results for the control of the pest, and further studies are needed to assess the host range of T. mitsukurii in Europe and the factors influencing its distribution.La cimice asiatica, Halyomorpha halys, è una specie invasiva nativa dell’Asia orientale, introdotta in USA, Europa e Sud America. Questo insetto dannoso si sviluppa a carico di più di 170 specie vegetali tra cui diverse colture frutticole, orticole, estensive e piante ornamentali. È in grado di causare danni alle colture e provocare fastidio alla popolazione umana quando si sposta nelle abitazioni per svernare. Nella presente tesi sono stati considerati alcuni aspetti relativi ai processi di invasione, all’impatto del fitofago sulla vite e agli effetti di fattori abiotici (alte e basse temperature) e biotici (controllo biologico) che possono influenzare la dinamica di popolazione di H. halys. Lo studio della struttura genetica dell’insetto associata a quella del suo simbionte primario, ‘Candidatus Pantoea carbekii’, ha permesso di chiarire le vie di invasione della cimice asiatica. Alcune popolazioni del nord-est d’Italia hanno mostrato la più alta variabilità genetica, suggerendo eventi di colonizzazione multipli da aree diverse. Nello studio delle dinamiche di popolazione stagionali di H. halys in vigneti multi-varietali è emersa una maggiore presenza dell’insetto su alcune cultivar a bacca rossa rispetto a quelle a bacca bianca, così come sono stati osservati livelli più elevati d’infestazione nelle zone di margine dei vigneti rispetto al centro. In studi specifici è emerso come le infestazioni di H. halys possano causare danni alle bacche, anche se è stata evidenziata una diversa suscettibilità varietale. Danni diretti sono rilevanti solo nel caso di elevati livelli d’infestazione, difficilmente osservabili in vigneto. Tuttavia è emersa una associazione tra l’incidenza di danni da Botrytis cinerea e la presenza di H. halys. Questo aspetto rappresenta la problematica principale dovuta alla cimice asiatica su vite e deve essere tenuta in considerazione nella definizione delle strategie di difesa. Gli studi sulle esposizioni a basse e alte temperature hanno dimostrato che gli individui a fine svernamento sono più sensibili alle alte e alle basse temperature rispetto a quelli che iniziano lo svernamento. Tra i primi, la mortalità degli insetti con livelli nutrizionali più bassi è stata maggiore in seguito alle esposizioni a basse temperature. Queste ultime hanno anche causato un aumento della longevità e una riduzione della fertilità nelle femmine svernanti. Lo studio evidenzia come l’esposizione a basse temperature possa influenzare il tasso di sopravvivenza e le dinamiche di popolazione di H. halys. Inoltre, le curve di mortalità derivate dallo studio sulle alte temperature possono essere impiegate per definire trattamenti termici per il controllo di H. halys. Infine, tra i parassitoidi oofagi di H. halys è stato ritrovato in nord Italia la specie asiatica Trissolcus mitsukurii, che ha mostrato un importane impatto sulle uova dell’ospite. Grazie a dei marcatori molecolari è emerso come gli individui del parassitoide raccolti in Italia siano affini ai campioni raccolti in Giappone e Cina. Lo studio sul complesso di ooparassitoidi naturali di H. halys in nord Italia fornisce risultati promettenti sul controllo del fitofago, ma ulteriori indagini saranno necessarie per valutare l’insieme di possibili altri ospiti del parassitoide in Europa, così come i fattori che ne influenzano la distribuzione
Nysius cymoides (Hemiptera: Lygaeidae), a potential emerging pest: overview of the information available to implement integrated pest management
No full textGivira ethela (Neumoegen and Dyar, 1893) (Lepidoptera: Cossidae), a previously unidentified pest on Vitis vinifera (L.)
Full text linkGrape cultivation is a billion-dollar agricultural sector in California, where invasive or novel pest species can disrupt management practices. We report herein on a new pest associated with California vineyards, the carpentermoth Givira ethela (Neumoegen and Dyar, 1893). Rather than an invasive species, G. ethela appears to be a newly recognized wood-boring pest of Vitis vinifera (L.) in regions of California’s Central Valley, where its initial occurrence has been dated back to, at least, the beginning of the 2000s. The habitus of adult, genitalia and pupa is illustrated. Givira ethela distribution in California is updated including published records and new data. Carpentermoth galleries seem to facilitate the access of Planococcus ficus Signoret, 1875 to vine sap and protection from natural enemies, environmental stresses, and pesticide treatments. Notes on pest status, life history, monitoring practices, natural enemies, and management options on grapes are also discussed. Tools for the Integrated Pest Management of G. ethela should include the correct identification of the insect and its damage, a full understanding of its biology and ecology, the application of monitoring methods, and the identification of economic thresholds and injury levels
Invasive brown marmorated stink bug (Hemiptera: Pentatomidae) facilitates feeding of European wasps and ants (Hymenoptera: Vespidae, Formicidae) on plant exudates
Full text linkThe brown marmorated stink bug, Halyomorpha halys, is a polyphagous species from eastern Asia, which has spread to America and Europe where it damages many crops. In recently colonized areas, facilitative interactions between H. halys and native insects are poorly investigated. In this study, we report for the first time facilitation of native wasp and ant feeding by H. halys in Europe. The facilitation was related to the outflow of plant exudates caused by H. halys feeding on manna ash trees, where they have aggregated in response to an aggregation pheromone, which then attracted species of Hymenoptera to the infested trees. Trees other than manna ash were not involved in the facilitation between these two taxa. The species that frequently visited infested manna ash were Polistes dominula, Vespa crabro, Formica (Serviformica) cunicularia and Lasius emarginatus, while Polistes cf. nimpha, Vespula germanica, Crematogaster scutellaris and Tapinoma subboreale were occasional visitors. The numbers of wasps and ants feeding on plant exudates differed at different times in a day, with more Hymenoptera foraging in the afternoon, when more H. halys individuals were actively feeding. Facilitative interactions, such as those recorded in this study, are important for furthering our understanding of the ecology of invasive species in terms of creating sources of food for native organisms
Effetto delle alte temperature sulla mortalità di Halyomorpha halys (Heteroptera: Pentatomidae)
No full textField Survival of the Brown Marmorated Stink Bug Halyomorpha halys (Hemiptera: Pentatomidae) on California Tree Crops
No full textHalyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a polyphagous insect pest that has invaded much of the United States, including California. Despite model predictions that regions in California like the agriculturally important Central Valley are suitable, H. halys populations and the occurring crop damage are distinctly lower than in regions of the East Coast. To evaluate if this is due to low nymphal survival in the high temperature and intensive monoculture environment, H. halys nymphs were caged on four common Central Valley tree crops: almond, pistachio, peach, and grape, and compared to the well-established almond and pistachio pest Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae). Nymphal development showed that peach, almond, and pistachio can sustain H. halys as single host plants until adult eclosion, whereas grapes cannot. The addition of fruiting structures of almond, pistachio, and grape to H. halys caged on peach trees (= mixed diet) did not increase nymphal survival but did increase adult female size. Leptoglossus zonatus survival was higher than H. halys on pistachio, but not on the other crops. Overall, H. halys nymphal mortality in the field was high, with 92% in the mixed diet compared to 73% in the mixed diet control in the laboratory, indicating abiotic population pressures. Our results confirm peach as a good H. halys host plant and suggest that almond has a similar suitability, and while pistachios can support H. halys nymphal development, they seem less likely to facilitate population growth
Effect of exclusion net timing of deployment and color on Halyomorpha halys (Hemiptera: Pentatomidae) infestation in pear and apple orchards
Full text linkThe brown marmorated stink bug, Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae), is an invasive pest species native to East Asia that has become the major pest for many crops, causing serious economic damage. The occurrence of this invasive pest leads to an increase in broad-spectrum insecticides applications, often with limited results in H. halys management. Exclusion netting based on insect-proof nets is considered an environmentally friendly tactic that may potentially reduce H. halys infestation and damage. In a first experiment, during two growing seasons we investigated whether the timing of exclusion netting deployment affected season-long H. halys infestation and impact on apple and pear production. A second experiment considered the effect of netting color. Our results confirm that insect-proof nettings are effective in controlling H. halys infestations in fruit orchards, also observing an effect of timing of netting deployment on H. halys adult infestation, especially in apple orchards. Netting deployment could be delayed until the growing fruit phase on pear orchards, while on apple orchards it should be performed at flower fading phase. Brown marmorated stink bug infestation and damage were also influenced by the netting color, with black nets having higher infestation levels and fruit damage than white ones. Within an integrated pest management framework, early net deployment and the use of clear color nettings should be considered to reduce H. halys infestation and its damage in pome fruit crops
Comparing the feeding damage of the invasive brown marmorated stink bug to a native stink bug and leaffooted bug on California pistachios
Full text linkCalifornia currently produces about a quarter of the world’s pistachios. Pistachio nuts are susceptible to feeding by stink bugs and leaffooted bugs; therefore, the invasive presence of the highly polyphagous brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a concern to California pistachio growers. We aimed to assess the potential of H. halys to cause yield loss and nut damage to pistachios, which had not yet been assessed in the field. Over two years, terminal branch ends with pistachio clusters were enclosed in organdy cages from spring to fall and exposed to either H. halys, the native stink bug Chinavia hilaris Say (Hemiptera: Pentatomidae), or leaffooted bug Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae), for 4–7-day feeding periods at different times of the season. We found that H. halys adults cause more epicarp lesions (external damage) when recorded at harvest time than the native species. They did not, however, cause more kernel necrosis (internal damage) than the two native species tested, which is a more relevant damage criterion for commercial production. There were no differences among insect species for any other recorded damage criteria. We conclude that H. halys could cause similar damage as the native species but note that H. halys population densities in California are still low and future damage levels will be dependent on this pest’s population density
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