1,720,975 research outputs found
Insetticidi a base di oli essenziali di agrumi: un’opportunità per il controllo degli insetti nocivi
No full textSinghiella simplex (Singh) (Hemiptera: Aleyrodidae), a new aleyrodid species for Italy causing damage on Ficus
No full textThe ficus whitefly Singhiella simplex (Singh) (Hemiptera: Aleyrodidae) is recorded for the first time in Italy. It was detected in Reggio Calabria (Southern Italy) in a public garden. The monitoring of its presence has highlighted its distribution in most of the city's urban green areas. S. simplex was found on Ficus benjamina and F. microcarpa trees, most of which were severely defoliated. The wide distribution and the high level of the infestations suggest that the introduction of this insect is not recent
Bioactivity of essential oil-based nano-biopesticides toward Rhyzopertha dominica (Coleoptera: Bostrichidae)
No full textEssential oils (EOs) are promising active ingredients to produce biopesticides, although their physicochemical characteristics are a critical issue to develop commercial formulates. Repellent and toxic activity of EOs against crop and stored product pests has been widely investigated in the last decades; however, no information is available on the occurrence of adverse undesirable behavioral responses (i.e. habituation) toward these repellents in target pest species. In this study, stable EO-based nano-emulsions from commercial fennel (Foeniculum vulgare), mint (Mentha x piperita) and sweet orange (Citrus sinensis) EOs were developed, and their repellence was tested against a major stored product pest, the lesser grain borer Rhyzopetha dominica. Besides, the occurrence of habituation in R. dominica adults following successive exposure to the repellent formulations was evaluated, considering the main characteristics of this kind of non-associative learning. Nanometric droplet size was achieved for all developed nano-emulsions (<200 nm). All the tested EO-based nano-formulations were repellent to R. dominica, whereas F. vulgare-based nano-emulsions triggered lower repellence both in area choice and arena bioassays. The occurrence of habituation was validated for the strongest repellents, M. piperita and C. sinensis formulations and the decline of R. dominica responses was frequency-dependent. Furthermore, insects completely recovered their responsiveness toward the biopesticides just after 24 h from the end of exposure. The decline of the responsiveness in R. dominica adults was attributable to real learning process, since motor and sensory fatigue were excluded by testing stimulus specificity and dishabituation. The results demonstrated that habituation could occur for repellent EO-based formulations, thus this behavioral process can reduce the effectiveness of these kind of treatments against R. dominica and should be considered to articulate adequate IPM programs against stored product pests
Essential oil-based nano-biopesticides: Formulation and bioactivity against the confused flour beetle Tribolium confusum
No full textPost-harvest pest control can rely on few approved pesticides and tools; hence, there is a rising interest in new sustainable, eco-friendly approaches. In this study, eight commercial essential oils (EOs) (anise Pimpinella anisum, artemisia Artemisia vulgaris, fennel Foenicum vulgare, garlic Allium sativum, lavender Lavandula angustifolia, mint Mentha piperita, rosemary Rosmarinus officinalis, and sage Salvia officinalis) were selected for their bioactivity and commercial availability, and then formulated in nano-emulsions. Repellency and acute toxicity of the developed nano-formulations were tested against a key stored product pest, Tribolium confusum (Coleoptera: Tenebrionidae). All the developed nano-emulsions presented optimal physical characteristics (droplet dimension = 95.01–144.30 nm; PDI = 0.146–0.248). All the formulations were repellent over time tested against adult beetles, in area preference bioassays. The best repellent was the anise EO-based formulation (RC50 = 0.033 mg). Mortality values from cold aerosol trials showed that the majority of tested EOs caused immediate acute toxicity, and garlic EO nano-emulsion caused the highest mortality of T. confusum adults (LC50 = 0.486 mg/L of air). EO-based nano-insecticides, used as cold aerosol and gel, are promising control methods against stored product pests, which can be integrated and combined with other sustainable biorational approaches
Volatile infochemicals from Rhyzopertha dominica larvae and larval feces involved in Theocolax elegans host habitat location
No full textThe development of biologically based approaches for stored product pest control is needed to reduce chemical inputs. Bioassays were performed to investigate host habitat location in the trophic interaction durum wheat/Rhyzopertha dominica/Theocolax elegans. GC-MS analyses were carried out to identify some chemical compounds produced by the host-related substrates. Choice and no-choice experiments demonstrated that female parasitoids were poorly attracted to intact kernels with respect to the infested substrates. Furthermore, T. elegans females performed longer residence time on infested wheat, and they generally displayed a short-term like fidelity for this cue, remaining on it during the whole observation. Infested wheat emitted one chemical (fenchone), which is possibly linked to host larvae presence, while the feces produced by host larvae emitted some other characteristic compounds. Results demonstrated that the presence of host larvae is a key factor for T. elegans host habitat location, considering that the attractiveness of the undamaged wheat is irrelevant. Furthermore, parasitoid females tended to stay on attractive cues, limiting the risk of contamination of other commodities. Biological control tools may be useful to improve the efficiency of pest management programs, but their application should be carefully evaluated
Male courtship behaviour and potential for female mate choice in the black soldier fly Hermetia illucens L. (Diptera: Stratiomyidae)
No full textThe black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae) is a promising
species used as protein source for aquaculture and zootechnical diets, which has been also proposed
as biological tool for managing organic wastes. Here, we investigated the courtship and
mating behaviour of H. illucens, recording the behavioural sequences displayed, the occurrence
of same-sex interactions and the role of female-borne signals eliciting male courtship. The
sequence of events leading to successful copulation is not dissimilar from other stratiomyid
species, although H. illucens females were able to convey their preferences for mates according
to male courtship behaviours. Males performed wing fanning during courtship prior to move
backwards on the female body. Once the males mounted the females, they tapped the female
abdomen with the tarsi of its second and third pairs of legs and attempted to accomplish preliminary
genital contacts. Male wing fanning during mounting attempts seemed pivotal for female
acceptance. Same-sex courtship behaviours were observed among males, which were not able
to distinguish between males and females during the in-flight approach and the mounting
attempt. Wing fanning played a key role also in evoking behavioural responses of males.
Indeed, the males just approached conspecifics beating their wings during flight, while no courtship
was recorded toward females that did not perform wing beating. This study improves the
knowledge about sexual behaviour of H. illucens, highlighting the role of wing fanning among
the range of sensory modalities used in the sexual communication of stratiomyid flies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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